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Improving Blade Quality: Challenges and Opportunities with Mohammed Fajar
Rosemary had a great discussion with blade expert Mohammed Fajar about blade defects, the blade design and certification process, and how optimization and automation could improve blade quality. Mohammed provides perspective on recent issues with turbine OEMs like Siemens Gamesa, and expresses optimism about wind power’s future, particularly offshore! With both of their extensive blade knowledge, they explore how human factors in blade manufacturing lead to inconsistencies and why the industry struggles to implement more automation.
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Rosemary: Hello and welcome to a special episode of the Uptime Wind Energy Podcast. I’m Rosie Barnes and today I’m joined by Mohamed Fajar, founder and blade consultant at Apex Wind. We used to be colleagues actually at LM Wind Power when Mohamed was a senior structural design engineer who took five blade designs through the certification process.
So wind turbine blade defects are very topical at the moment with what’s in the news with Siemens Gamesa and also TPI, we’ve talked a lot about that on the podcast. And I thought that Mohammed would be the perfect person to have on to tell us about how the blade design and certification process works, or maybe more accurately how it should work to ensure that blade defects aren’t a problem.
They’re not supposed to be. So thanks heaps for coming on, Mohammed.
Mohammed: Thank you for inviting me.
Rosemary: So I just wanted to start out. Can you tell us a little bit about your background and what you’re doing now at Apex?
Mohammed: I graduated in 2014 as a master in engineering in France about composite structures and materials.
And since then I joined LM Wind Power in Denmark and my journey with blades started. So I started as a structural design engineer. Yeah. As you say, designing blades, for various OEMs, uh, taking them from the conceptual design to the Yeah. Manufacturing and handover to, to the factories. Also worked at yeah, a company called R& D test systems also in Denmark doing test systems for wind.
And then another three and a half years in Vestas in the innovation department. I was working a little bit as the blade owner in the department tech lead in, in all blade related projects. One of them, it’s the, yeah, cable stay drawtor where I also worked on it from the start to almost the end of it.
And then since July 23 I went on my own. I started Apex Wind, as you mentioned, and the goal is, yeah, to have this. It’s a consultancy company, a hundred percent focused on blades. Uh, helping developers, OEMs and startups yeah, to have a blade expert on the side when they need it.
Rosemary: Yeah. It’s good timing to pick a company like that, founding a company like that, because it’s definitely such a need for blade consultants these days, but with yeah, all of the issues that we’re seeing.
Mohammed: Yeah. One of the things that really motivated me to get in, because when it was, for example, on the OEM side, sometimes I feel that there was a struggle finding someone who knows about blades and can help with blades.
Often you end up, even if you want some CAD resources, you end up hiring someone who works with steel or something, and then almost have to teach him how to work with composites. And there was never this full package for people who knows about the whole value chain of blades to know about the design and then the manufacturing, the certification, the testing.
Often I compare it to some other components of let’s just say the nacelle in in, in big companies. You will have the same number of engineers working on the nacelle as working on the blades. And in the place we’ll have all these specialists on lightning on, on foams, on glass and then on liquids and then paint. And that’s why actually sometimes it gets very hard to get that person who can cover all these areas at once.
But yeah, and then the demand is big, but also the issues and the struggles, often they make a lot of noise in the media, but also the cost a lot of money to both, yeah, OEMs, developers and insurances and insurers and so on. And yeah, actually had this. sentence or this mission, when I started, just try to make blades a little bit more reliable again. Because with all I thought, I don’t think there’s a specific person or company to blame, but there is this pressure on costs.
There is these quality issues that keeps coming and then The companies that are trying to fix it, they’re spending money on it, they start maybe spending a little bit of on innovation on new products and so on. And then you just end up just fixing what you have. And sometimes it gets too big that you stop selling some platforms or turbines like what’s happening to Siemens Gamesa at the moment onshore.
Yeah, if I can help a little bit with that, I will be very happy.
Rosemary: Yeah, it’s a timely service that you’re offering. And I think that a lot of manufacturers would be happy to have that resource available. I think maybe it’d be good to start out by giving some background for people that aren’t totally familiar with, what are the issues with blade defects these days?
Can you maybe help just summarize? So I’m talking about Siemens Gamaces their issues with, I think they’ve had some wrinkles and some issues with their bearings as well. Maybe not so specifically blade related. Last time that I checked in, they were up to quite a few billions of dollars in expected cost to remedy that.
And then there’s a little bit from TPI as well, not to the same extent. Is that the issue as you said, or do you have anything to add about what the state of wind turbine blades are these days?
Mohammed: Actually, yeah, there is actually Yeah, a big group of blade defects that happens and some of them happen just during the transport and sometimes they’re just aesthetic.
Majority of them, or like at least the ones that have worse consequences, is the ones that happens often in the factory or even worse during the design. But actually what happens during the design, I have just a feeling that it’s maybe OEMs, they will have a really hard time to admit it. So often outcome of the root cause will come as manufacturing and we all can do, cannot do much except trusting that.
But yeah, in the factories, actually, there is a lot of NDT, non destructive testing that you can do in UT scanning and so on. And you can, again, you find the defect that you find, and then the ones that you don’t find, that’s the one that goes in the turbine.
And that’s the ones that we hear about them a few years later. And yeah, you mentioned wrinkles, wrinkle, it’s actually it’s main and one of very dangerous defects that happens. Yeah, as you said, Siemens Gamers, they also mentioned they had one of these defects in the platforms. They have stopped and they’re actually the physics are easy. Like you have laminate, if half of it is wrinkled, then basically you lose half of the strength. And then once the part that is not wrinkled cracks, then the part that is wrinkled it gets straight and then cracks again. Now actually a lot of days they have these protrusions, carbon protrusions where wrinkles, it’s less of an issue because you can actually control it before placing it on your blade.
But at least let’s say in the root part where you cannot use these protrusions wrinkles yeah, are very present. And sometimes you cannot even find them with this UT methods because if there is just some foam in between the glass, then you cannot get the signal anymore. And let’s say they don’t come from your design and then you have, you design a blade and then mark and then you fix.
You manufacture it in four different locations in Europe and South America and China, you can get three blades that are almost completely different because at one point your design documentation and QMS systems and quality and so on, it has some limitations. And then it ends up at the hands of the people, placing those plies and applying that vacuum and gluing your blade together.
And that’s actually one of the main struggle that people try or OEMs trying to fix, but you do your best, you train people and so on. But there is, yeah, there’s a big turnover in in, in those factories and you end up sadly with, in some cases and actually the CEO of Siemens Games mentioned it in his call last week that he mentioned the Mexico factory. Then it means that Okay, sometimes just one factory can have a lot of defects that some other factories doesn’t have.
And even if your design and all your processes are exactly the same, right? And this also proves or shows how complex is the whole situation because that blade the if it’s designed in, I don’t know, in, in the US or in China, you, it is the same certificate and it’s certified by the same certification body and everything is checked in the same way, but at the end you will manufacture it in two places.
You might get two places that are pretty different actually.
Rosemary: That’s a really good little teaser for the issue that I want to get to at the end. And it raises the whole point of what I wanted to talk to you about, which is how are we supposed to make sure that doesn’t happen. That you just have blades of random quality making it onto wind turbines, which I think is every, wind farm owners biggest nightmare is that, they’ve bought these very expensive wind turbines.
How do they know that they’re not going to the blades aren’t just going to snap off. So I was hoping that you could walk us through step by step, how the process works, so starting off with yeah, how do you even design a blade, a wind turbine blade, and then what is the certification, the manufacturing, the quality checks, how does that work to yeah, supposedly ensure the high quality of all these blades.
And then maybe after you’ve talked about all that, we can go through how it goes wrong and why?
Mohammed: First you will decide that, okay, there is a specific type of turbine that you’re interested in making. Then actually you will have your loads team and aero team and also a little bit the structural team working on defining just the big parameters of this turbine, the exact diameter, the core distribution, the twist, uh, and so on.
And then the outcome of that first step will be an outer geometry of your blade that still might be changed later on during the design phase. But as they say, the big dimensions are fixed and then a good idea about your loads the fatigue loads and then the static loads in the different direction that you will need to design the blade for.
Once you have that, then you will have the structural design engineers starting working. And basically what they will do, they have different tools and then they will start placing almost layer per layer. You can have like thousands of layers sometimes in some blades. Placing that, running your analysis with the loads and then checking the main first failure modes or design drivers, let’s say the strain distribution, the buckling in some panels on the blade. And then iterating, a lot of iterations, adding a little bit of material here, removing from there, checking your load models, making sure that the loads don’t go up too much. Checking some constraints you might have, maybe some tip to tower clearance, maybe some specific ion frequencies that you want to avoid.
And at the end of this first step, then you will have a first kind of conceptual design with the right geometry, the right trailing edge thickness, the right blade circle diameter, root circle diameter. Once you get all that, then actually you go one step further into your design and you start doing some finite elements analysis, which is a little bit some more details analysis on like very small details on your design.
So once you get all that done, then you start involving the certification actually, which is a third party that often the customers will ask for them to certify your product. And then you start sharing with them some of your models. And while they are doing that, you will actually start preparing your full scale testing, because every blade needs to go through a full scale test. And in that phase, you also have some people from the third party certifying your blades coming and doing some audits. Yeah, you manufacture the blade, you ship it for testing. You do full scale tests which take actually many months, the fatigue testing, it’s many millions of cycles.
And then you have to do a static or extreme test before and after that one. And then depending on how much risk you want to take, you can launch the full the serial production before the end of the testing, because often you cannot afford waiting six months or a year for the testing to be completed.
Rosemary: I’m assuming that the team on the certification company is not as big as the team at the manufacturer. So how can they possibly check all of that information in enough detail to be sure that you’ve done it right? Or are they then relying on the fact that you’ve made a test blade didn’t break that means everything’s okay. I just how do they get enough certainty from it?
Mohammed: They check what they can do. They cant rebuild the models, maybe some try to build some the, that finite element modeling and run it. But no matter what they do, they will have to put a lot of trust in what you have done. As I said, there’s many people working on that blade design sometimes can easily go up to 50 or a hundred. And then when you look at the certification parts, two or three people working, for example, on that structural design part, or even less.
They will not certify that this blade is perfect, but it was again, certify that you follow the steps that you have to, and you follow this IEC standard 61400 for lightning or for structural or for testing. And so the system has large limitation and that’s also why, for example, many developers, they have their own qualification system.
Of course. The certification you need to certify, but themselves, they will try to look at some design parameters. They have, they will look again through the, I don’t know, the power generation data. They will go and do some audits in the factories. And even after doing this you catch what you catch and then what you don’t know, you probably never know it.
And some defects, they appear during the lifetime and some they don’t even appear actually because they’re not that problematic. And we learned to live with that. I would say the majority don’t have any problems, but if you are a developer, you don’t want to get those ones that fail so you have to do all these checks.
Rosemary: Okay, so I’ve got a follow up question. I know that you mentioned that you make usually one test blade. It’s one of the first blades that you have made. There’s a high chance that it you know, has a lot of the issues in it that you haven’t figured out yet. I’ve spent a lot of time in wind turbine blade factories, and I know that every blade that comes off the end of a production line is not exactly the same. There’s different defects in every blade and they’re always doing repairs.
So how can you hope to capture the whole range of problems that you might have if you just test a single blade? How does the certification process deal with that or the design and certification process, is a better question to ask.
Mohammed: If you do some lab tests of small composite parts, you really need to test a big population to really be certain of integrity of that part.
In blades it’s a bit different because we talk about blades of 100 meters, it’s a high cost, and it’s also every blade takes many months, so you cannot afford doing seven tests, it will ruin the whole business. One way of dealing with it it’s basically with partial coefficients. So in, in the certification standards, basically because of the, this variation in manufacturing, you will add a factor of, I don’t know, just saying random numbers of 1. 1. Because of this variations in fusion or in, in the uncertainties about your load model and so on. You will keep adding these small partial coefficients and then you end up sometimes depending on your process, you end up with, I don’t know, partial coefficient of, let’s say two.
And that’s already actually means that your blade, it’s actually two times stronger than the nominal one, but it’s because there’s a lot of variations again. And then there is variations in the loads, there is variations in the structure and you don’t want these variations to start overlapping that you will have in some cases a blade that is weak enough because of all these deviations.
And then a load model that is not conservative enough that you will end up with these blades failing. And then you also do overtest actually those blades to some level. In static you will test them 10 percent more and then in fatigue depending on your number of cycles and your strain, you might test it up to 33 percent more.
Rosemary: No matter what your best efforts are sometimes you are going to get, defects that occur occasionally in serial production that didn’t happen in the test blade. Or I guess you do get the occasional unlucky blade where just every single possible parameter you’re at your worst case scenario, and they will all line up like holes in Swiss cheese.
So then you see issues like what we’re seeing in the news today with Siemens Gamesa, TPI, the main ones that I’ve heard of, which you’ve already talked about today. Do you feel like there are more blade defects than normal at the moment?
If you do think that there’s more than the normal amount of defects, what’s your thoughts on why that is and what that means for the future of wind?
Mohammed: Actually, I think there’s much less defects than before.
Because also, actually, there was a lot of progress yeah, but when just the engineering part, there was some, actually now more, much more calculation is done than before. And also in the manufacturing with all these new methods of being lean and then the quality management system and so on. I think they are getting less, but actually the ones that still makes it to the blades, those defects, they have a bigger impact now because we’ll, we became better, I think, as making blades at making less defects, but we also squeezed all the kind of the juice where we really pushing the limits and then going really designing to the limits and so on.
So maybe before you would have 10 small defects because of your manufacturing, but you had a little bit extra capacity in your structure that did want to be a problem. But now maybe let’s say you have just one out of these 10, but because of The very optimized blades, I would say one wrinkle that you don’t catch might be a big problem.
And that’s why having control over your manufacturing, it’s actually, it’s so important if you want to keep innovating, bringing new materials and then having this detailed analysis that you can use. You cannot benefit from that if you’re manufacturing is not like really almost perfect.
And that’s the problem I think blades have. I think almost everybody will agree with me. It’s the manufacturing that is still very like labor intensive. And then when it’s humans making that, it depends on where they are, if they had a bad night, if they have paid well, if they are stressed and all these factors, actually. You can have the best design you want.
You can reduce the number of defects, but yeah, the human factor is so important and then how can that be fixed? Often it will require money. And then again, the business case start suffering. Because you can say that why aren’t we automating all this process some simple ones like placing glue or placing some layers?
But, I worked in some many actually projects trying to add automation into factories. Very often you end up having more expensive blades that nobody will want to buy. And then you end up somehow, I don’t know if it’s intentionally or not admitting to like to have this quality issues than to invest in automation and then remove these quality issues.
Because at the end, even if those blades fails, it’s still actually better business case than a fully automated factory.
Rosemary: Okay. That’s a, yeah, that’s a really good perspective. And maybe we’ll have you back on another time to talk about wind turbine blade manufacturing, because I think that’s a whole huge topic that people don’t necessarily understand that well.
Yeah, particularly how manual the process is and all the quirks of composite materials. Thanks so much for coming on. And can I just ask a parting question? What do you think the future for wind is? Are we going to, make it out of this current crisis? Will we see bankruptcies? Do you think it’s overblown?
What’s your little snapshot of where you think we’re going?
Mohammed: I think there is still a future for wind, also mainly for offshore. Actually, it looks very promising. LCOE, it’s just decreasing and decreasing. And maybe that’s also why we are seeing all these problems. But I think it will stabilize at one point. I hope that will happen.
And then we have this healthy kind of industry where nobody’s taking kind of the losses. If it’s a supplier, OEM, or a developer, or the end customer. I think actually, I’m very positive, I would say. And then I think the solution in all that will often be, yeah, technology and innovation. I know also trying to keep the amount of platforms and product existing in the market very limited so that OEMs can benefit from it.
But only the market can regulate itself. And only the market will regulate the size of turbines. Only the market will regulate the end price. And it has to converse to a good balance point.
Rosemary: Thanks a lot for listening to this episode of the Uptime Wind Energy podcast. Don’t forget to like and subscribe if you’re watching on YouTube. Or if you are listening on a podcast, please leave us a review. It makes a big difference to other people finding the podcast. Yeah, thanks again and we’ll see you in the next episode.
Improving Blade Quality: Challenges and Opportunities with Mohammed Fajar
My personal reaction to Trump flags is more of pity than offense. Life is tough enough without being deprived of a moral compass and even a meager level of intelligence.
In any case, we see such displays in ever-decreasing numbers, as Trump’s approval rating continues to fall, due to the president’s cognitive decline and brazen criminality.
One has to wonder how much more gas Trump has in the tank when he calls those who disapprove of him (especially blacks and women) “low IQ.”
Aren’t we approaching a point when this type of stupidity will cease to be effective?
There must be a bottom of the pit we’ve fallen into.
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PowerCurve’s Innovative Vortex Generators and Serrations
Nicholas Gaudern from PowerCurve joins to discuss SilentEdge serrations with up to 5 dB noise reduction, Dragon Scale VGs for AEP recovery, and their approach to products that actually perform in the field. Contact PowerCurve on LinkedIn for more information.
Sign up now for Uptime Tech News, our weekly newsletter on all things wind technology. This episode is sponsored by Weather Guard Lightning Tech. Learn more about Weather Guard’s StrikeTape Wind Turbine LPS retrofit. Follow the show on YouTube, Linkedin and visit Weather Guard on the web. And subscribe to Rosemary’s “Engineering with Rosie” YouTube channel here. Have a question we can answer on the show? Email us!
Welcome to Uptime Spotlight, shining Light on Wind. Energy’s brightest innovators. This is the Progress Powering tomorrow.
Allen Hall: Nicholas, welcome back to the show.
Nicholas Gaudern: Thanks, Allen. Always a pleasure.
Allen Hall: Well, there’s a lot of new products coming outta PowerCurve. And PowerCurve is the aerodynamic leader in add-ons and making your turbines perform at higher efficiency with less loss. Uh, so basically taking that standard OEM blade and making it work the way it was intended to work.
Nicholas Gaudern: Yes. We
Allen Hall: like to
Nicholas Gaudern: think so. Yeah.
Allen Hall: And there’s a, there’s a lot of new technology that you’ve been working on in the lab that you haven’t been able to explore to the, introduce to the world, so to speak. Yeah. And we’ve seen some of it from the inside of, you know, you’re working behind the scenes or working really hard to get this done, but now that technology has been released to the world, and we’re gonna introduce it today, some new trailing edge.
[00:01:00] Components. Yeah. That really, really reduce the noise. But they, they look a little bit odd. Yes. There’s a lot of ADON dams going on with
Nicholas Gaudern: Yeah.
Allen Hall: With these. So what, what do you call these new trailing edge parts?
Nicholas Gaudern: So, so what you have in your hand here? This is the Silence edge, uh, serration. So this is our new trailing Edge Serration products.
Now, most people, when they think of training restorations, they are thinking of triangles.
Allen Hall: Exactly.
Nicholas Gaudern: These Dino tails. Dino Tails, that’s the Siemens, Siemens name for them. Pretty, pretty standard. You see ’em on a lot of turbines now. Sure. And they work, you know, they do do a job. They do a job. They reduce noise.
But like with lots of things in, in aerodynamics, there’s lots of different ways that you can solve a problem and some are better than others. So we’ve worked for a long, long time in the wind tunnel, uh, in the CFD simulations, and we’ve come up with this pretty unique shape. We think,
Allen Hall: well, the, the, the shape is unique and if you, if you look at it, there’s actually different heights to the, the triangle, so to speak.
To mix the air from the pressure and the [00:02:00] suction side to reduce the, the level of noise coming off the blade
Nicholas Gaudern: e Exactly. So we have, uh, we have an asymmetry to the part. We have these different tooth lengths. We have, uh, a lot of changes in thickness going on across the part. So it may be a little bit difficult to see on the camera, but these are quite sculpted 3D components.
They’re not, they’re not flat stock white triangles. No, no. There’s a lot of thickness detail going on here. We’ve paid a lot of attention to the edges. We’ve paid a lot of attention to these gaps between the teeth as well. So all of this is about trying to figure out what is the best way to reduce noise.
And something that not a lot of people will, will admit, but it’s true, is that as an industry we don’t really understand the fundamentals of how serrations work.
Allen Hall: It’s a complicated
Nicholas Gaudern: problem. It’s a really complicated thing. Problem, yeah. Yes. So trying to simulate it in CFD is an absolute nightmare. The, the mesh sizes required, the physics models required are really, really difficult.
So what we found is that you’re probably better off spending [00:03:00] most of your time and money in the wind tunnel. Yes. So, so we go to DTU, they have this wonderful, uh, air acoustic wind tunnel, the pool of core tunnel. It’s one the best tunnels in the industry for doing this kind of work. It
Allen Hall: is
Nicholas Gaudern: because you can measure acoustics and aerodynamics at the same time.
So this allows us to do a lot of very cost effective iteration for this kind of design work. So we know what’s important. You know, we’ve, we’ve studied all the different parameters of serrations lengths, aspect ratios, angles, thicknesses, all this kind of stuff. And it’s about bringing them together into a, into a coherent product.
So this is, this is a result of a lot of design of experiments, a lot of iteration, and combining wind tunnel and CFD to kind of get the best of both of those tools. So,
Allen Hall: so what’s the. Noise reduction compared to those standard triangular trailing aerations. Yeah.
Nicholas Gaudern: So there’s lots of different ways of, of thinking about noise reduction, but I think probably the most useful is the O-A-S-P-L.
So this is the overall sound pressure level. Right. Is kind of what [00:04:00]typically you’ll be measuring in an IEC test.
Allen Hall: Right.
Nicholas Gaudern: And that’s measured in decibels, but a way to decibels because it’s important that we’re waiting to what the human ear can actually hear. Right. Perceive. Exactly. So that’s the numbers we report.
For the field test we’ve recently completed with Silent Edge, we’re seeing up to five decibels of O-A-S-P-L noise reduction.
Allen Hall: Okay. So what’s that mean in terms of what I hear on the ground?
Nicholas Gaudern: So that is an absolutely huge reduction. It’s multiple times of reduction because you know, decibels on a log scale,
Allen Hall: right?
Nicholas Gaudern: So five DB is is enormous. It’s
Allen Hall: a lot. Yeah.
Nicholas Gaudern: And what’s really interesting is that if you have a turbine that’s running in a noise mode, just one decibel reduction. Of power, sound, sound, power level might be three or 4% P loss. I mean, that, that’s, that’s huge. Think about that loss. So if you need to reduce noise by five decibels to get within a regulation, imagine how much a EP you have to throw away by basically turning down the [00:05:00] turbine to do that.
Allen Hall: That’s right.
Nicholas Gaudern: So that’s really what the, the business case for these kind of products is. It means you can escape noise modes because as soon as you use a noise mode. You are throwing away energy.
Allen Hall: You’re throwing well you’re throwing away profits.
Nicholas Gaudern: Exactly.
Allen Hall: So you’re just losing money to reduce the noise.
Now you can operate at peak.
Nicholas Gaudern: Yep.
Allen Hall: Power output without the creating the noise where you have that risk. Right. So, and particularly in a lot of countries now, there are noise regulations. Yes. And they are very well monitored.
Nicholas Gaudern: Yep.
Allen Hall: We’re seeing it more and more where, uh, government agencies are coming out and checking.
Yes. ’cause they have a complaint and so you get a complaint. Oh, that’s fine. Or someone can complain. Yeah. You know, you need to be making your numbers.
Nicholas Gaudern: Yep. And, and the industry needs to be good neighbors, you know? It
Allen Hall: certainly does.
Nicholas Gaudern: Uh, we have to make sure that people are, you know, approving and comfortable with having wind turbines in their backyard.
Sure. And noise is a big part of that.
Allen Hall: It is.
Nicholas Gaudern: So yeah. Ap sure. That’s really important. Being a good [00:06:00] neighbor also important.
Allen Hall: Right.
Nicholas Gaudern: Meeting the regulations. Obviously you have to meet the regulations. So this product, um, has been through a really long development cycle, and we’re now putting the final touches to the, to the tooling.
So this is available now.
Allen Hall: Oh, wow.
Nicholas Gaudern: Okay. Great. Um, and we’re hoping that in the next uh, few months we’ll be getting even more turbines equipped out in the field with, with the technology.
Allen Hall: So, oh, sure. There’s a, you think about the number of turbines that are in service, hundreds of thousands total worldwide.
A lot of them have no noise reduction at all.
Nicholas Gaudern: No. No.
Allen Hall: And they have a lot of complaints from the neighbors.
Nicholas Gaudern: Exactly.
Allen Hall: Trying to expand wind into new areas, uh, is hard because the, the experience of the previous Yes. Neighbor
Nicholas Gaudern: Yep.
Allen Hall: Grows into future neighbors. So fixing the turbines you have out in sight today helps you get the next site.
I know we don’t always think about that, but that’s exactly how it works. Yeah, of course. Uh, we need to be conscientious of the people of the turbines we have in service right now. So that we can continue to grow wind [00:07:00] globally and more regulations on noise are gonna come unless we start taking care of the problem ourselves.
Nicholas Gaudern: Yep. And another really important thing with Serrations is that you have to design them so that they don’t impact the loads on the rest of the turbine.
Allen Hall: Right. And people forget about that.
Nicholas Gaudern: Yes.
Allen Hall: Can you just, can’t just throw up any device up there. And think, well, my blade’s gonna be happy with it. It may not be happy with that device.
Nicholas Gaudern: You have to really carefully understand what the existing blade aerodynamic signature is.
Allen Hall: Sure.
Nicholas Gaudern: How is that blade performing? What is the lift distribution across the span? Yeah.
Allen Hall: Right. Yeah.
Nicholas Gaudern: So what we do, and we, we’ve talked about it before we go and laser scan blades. We build CAD models, we build CFD models so we can actually understand how much lift a blade can take and what’s the benefit or the penalty of doing so.
So these serrations are designed by default to be load neutral. They won’t increase lift. They won’t reduce lift. That’s what
Allen Hall: it should
Nicholas Gaudern: be. That’s where you should start,
Allen Hall: right?
Nicholas Gaudern: And maybe there’s some scope to do something else [00:08:00] on certain turbines, but you shouldn’t, you shouldn’t guess. You, you need to calculate, you need to simulate, you need to think very carefully about that.
So that’s what we do with these, uh, with these serrations, we go through this very careful aerodynamic design process to make sure that they reduce noise and that’s it. They don’t increase loads, they don’t reduce AP by killing lift. And that’s, that’s an important aspect.
Allen Hall: Well, that’s the goal.
Nicholas Gaudern: Yes,
Allen Hall: exactly.
I don’t necessarily want to increase power. I don’t wanna put more load in my blade, but people do that. I’ve seen that happen and man, they regret it.
Nicholas Gaudern: Yeah, regret it. There’s, there’s some pretty wild claims out there as well about observations can and can’t do. And uh, like with lots of things, it’s important to just do the simulations, speak to some experts and, um.
Yeah, maybe take the, the less exciting path, you know, sometimes,
Allen Hall: well, no. Yeah. Well, less exciting path where I don’t have a broken blade.
Nicholas Gaudern: Yeah, exactly.
Allen Hall: Yeah. That’s a lot less exciting. It’s, it’s definitely more profitable. Now, the Dragon Scale Vortex generator has been [00:09:00] around about a year or so.
Nicholas Gaudern: Yep, yep.
Allen Hall: And the thing about these devices, and they’re so unique, interesting to think about because you typically think of a vortex generator as this being this little bit of a fence.
Where you are tripping the air and making it fall back down onto the blade.
Nicholas Gaudern: Yep.
Allen Hall: A really, it works.
Nicholas Gaudern: It works.
Allen Hall: But it’s it’s
Nicholas Gaudern: been around a long time.
Allen Hall: Yeah. Yeah. It, it does, it does do this thing. And they, they were, they came outta the aviation business. We use ’em on airplanes to keep air flow over the control surfaces so we can continue to fly even in close to stall conditions.
All that makes sense. And airplanes are not a wind turbine.
Nicholas Gaudern: Yes.
Allen Hall: So there’s different things happening there. So although they work great on on aircraft, they’re not necessarily the most efficient thing for a wind turbine where you’re trying to generate power and revenue from the rotation of the blades.
Nicholas Gaudern: Exactly.
Allen Hall: So this is a completely different way of thinking about getting the airflow back onto the blade where it produces [00:10:00] revenue.
Nicholas Gaudern: And what’s really nice is to actually see this together with silent edge, because historically, and maybe not even historically. Serrations VGs, they’re triangles. They work, they do a job.
But that doesn’t mean you can’t do it in a different way. In a better way.
Allen Hall: Right.
Nicholas Gaudern: And that’s the same principles from applying with Silence Edge and Dragon Scale. We want to work the flow in the most efficient way possible.
Allen Hall: Right. You’re trying to get to an
outcome.
Nicholas Gaudern: Yeah, exactly.
Allen Hall: Efficiently.
Nicholas Gaudern: We want to, we want to target very specific things on the blade, and that’s where you can see there’s a few different styles of Dragon Scale that we have on the table here.
We have some that are two fins. We have some that are three fins. We have different sizes, and this is because they’re tailored to different parts of the blade. So these three Fin Dragon scales, their focus is ultimate lift. We are creating a really powerful vortex through this combination of three air foils, if you imagine, um, the inside of a Turbo fan.
You have these cascading air force. [00:11:00] You look at the leading edge slacks on an aircraft. You look at the front wing of a Formula one car. It’s that kind of concept.
Allen Hall: It’s like that,
Nicholas Gaudern: and it’s these air force that are cooperating with each other.
Allen Hall: Right.
Nicholas Gaudern: To end up with a more beneficial result. ‘
Allen Hall: cause an air force by itself does a function, but when you combine airflows together in the right way
Nicholas Gaudern: Exactly.
Allen Hall: You can really control airflow efficiently, less losses. More of what you want out the backside. Yeah, exactly. It’s, it’s the backside you’re trying to work on, on a VG or, or dragon scales. You’re trying to create this flow which gets the airflow back onto the blade to create power. We,
Nicholas Gaudern: we want as much attached flow as possible and down exactly down in the roots of a blade.
We have to have really thick aerofoils, you know, blades about round. They’re basically cylinders.
Allen Hall: Yeah.
Nicholas Gaudern: And that, that’s essential, right? We have to have the blade take a lot of load into the root aerodynamically. They’re horrible.
Allen Hall: Yeah.
Nicholas Gaudern: So this is where these, uh, these powerful Dragon Scale VGs come into play because what they do is they’re [00:12:00] reenergizing the flow over the aerofoils, and they’re ensuring that that flow remains attached for much, much longer than if those bgs weren’t there.
So down in the root, you’ll get significant boosts to the lift that those sections can generate. And what’s more lift? It goes to more torque, it goes to more power, goes to more a EP. So these dragon scale VGs in the root are there to boost, lift, and boost EP out on the tip of the blade. Things are actually a little bit different because it’s way different.
You shouldn’t really have stall there to begin with if your blade’s been designed well.
Allen Hall: But if you have leading edge erosion exactly. Or some other things that are happening, you can have real aerodynamic problems.
Nicholas Gaudern: So yeah, as soon as you have erosion, uh, maybe your stall margin is not as big as you thought it was.
You’re starting to get some significant losses of lift Yes out towards the tip of the blade. So that’s where these, uh, TwoFin uh, variants come in. So it’s still a dragon scale vg, it’s still the same concept of these cascading error foils. Yeah, but these are [00:13:00] designed for basically ultimate lift to drag ratio.
Mm-hmm. So we don’t really want more maximum lift outta the tip. We kind of have enough, but what we do want is to keep stable attached flow and we want to do it for the less, uh, least drag penalty possible. So basically we want to get rid of as much parasitic drag as we can. These two fin dragon scales, we are seeing 25 plus percent improvements in lift to drag ratio.
Compared to a standard triangle vg. I mean that’s huge.
Allen Hall: That that is really
Nicholas Gaudern: huge.
Allen Hall: That’s huge, right? Because people have seen these, uh, triangular VGs in a lot of places. And one thing I’m noticing more recently is that those VGs, because they’re so draggy, they tend to flutter and they tend to break in just off.
Nicholas Gaudern: Interesting.
Allen Hall: So you’re having this failure mode because this thing is just blocking the air, getting the air to trip.
Nicholas Gaudern: Yeah.
Allen Hall: It’s not efficient. It does have its downsides ’cause it is. D definitely drag. Just face it, it’s it, is it a draggy [00:14:00] 1940s technology? That’s what it is. Where with the dragon scales, now we’re doing things a lot more efficiently and thinking about how do I get the airflow that the blade designer originally wanted?
Nicholas Gaudern: Yes,
Allen Hall: because the blade designer, they’re really intelligent people. They’re, they’re sitting designing blades. But the reality is what you design is on an ideal airflow, and what you have out in service are totally different things. As, as it turns out, the shape of the airflow is not what you think it is because it comes out of the tool and there’s a lot of touching with by humans that are grinding on the leading edges and doing the things that have to be done to manufacture it.
So you don’t really have an ideal blade when it comes out of the
Nicholas Gaudern: No. You
Allen Hall: never do factory. No, you never do.
Nicholas Gaudern: And it’s not polished either.
Allen Hall: It’s not polished. Right. So
Nicholas Gaudern: when you go to the wind tunnel, you have a perfect profile. Yes. And it’s polished. And it works basically. It
Allen Hall: works great. It
Nicholas Gaudern: works great.
Allen Hall: The theoretical and the actual match.
Yeah. In reality they do. I think a lot of operators are not [00:15:00] connected with that reality of, Hey, that Blade should be producing this amount of revenue for me, and it’s not. And you hear that discussion all the time, particularly in the us. It should be producing this amount of power. I’m doing all the calculations.
We are not producing that power. Why? The blade length’s saying, but the power’s not coming out of it. Well take a look at your leading edge, take a look at your yard full of shape and realize you’re going to have to do something like dragon scales to get that E energy. Exactly. Revenue back.
Nicholas Gaudern: You need to do a full aerodynamic health check.
Basically you do. And see what are all the possibilities to improve my blade performance. And some of it is down to the fundamental shape of the blade,
Allen Hall: right?
Nicholas Gaudern: But some of it is down to blade condition. Yes. Blade Blade manufacturing quality.
Allen Hall: Yes.
Nicholas Gaudern: Uh, what kind of paint did they put on it? What day of the week was it made?
And all these things can be compensated for by VGs and you’ll get more revenue out at the end.
Allen Hall: You say? ’cause what happens? The, the, the scenario which is hard to visualize unless [00:16:00] you’re an A and emesis, is that there comes on the suction side, and it should be, in a ideal sense, rolling all the way to the back edge of the blade and coming off.
What happens is though, is that. When you get leading edge erosion is that the air flow actually separates. Yeah.
Nicholas Gaudern: It
Allen Hall: doesn’t
Nicholas Gaudern: always make it, yeah.
Allen Hall: Doesn’t make it to the back edge. Yeah. And so you can see that, especially if, if there’s dirt in the air, you can look on dirty blades, you can see where that separation line is, and a lot of operators have sky specs, images or Zeit view images, and then go back and look at the blades.
It takes two minutes to go. I have
Nicholas Gaudern: particularly down in the root, you’ll see it.
Allen Hall: Oh, in the root all the time. You, you
Nicholas Gaudern: see it really clearly that that separation line
Allen Hall: all the time, you really see that separation line. I’m seeing it more and more up towards the tip. Interesting. That’s where the lightning protection, yeah.
Systems sit.
Nicholas Gaudern: Yeah.
Allen Hall: I see a lot of airflow that is not front to back on the suc. Well, you
Nicholas Gaudern: have a lot of three dimensional flow out there.
Allen Hall: You do towards the tip you do. And you realize how much power you’re losing there. And I think operators are just throwing away money.
Nicholas Gaudern: Yeah, exactly.
Allen Hall: So you could [00:17:00] put dragon skills on it very efficiently, very quickly.
Get that revenue back into your system and it’s gonna stay. So even if leading edge erosion happens, the dragon scales are gonna compensate for it. It’s gonna get the airflow back where it should be.
Nicholas Gaudern: Exactly. And the nice thing about this is, you know, we are building on well over a decade of upgrading turbines with aerodynamic components.
Oh yes. So this technology stands on the foundations of all of that work. In terms of the materials, the work instructions. Um, the fatigue calculate, you know, everything
Allen Hall: Yes.
Nicholas Gaudern: Is built on thousands of installations that we’ve done. Yes. So, although it’s a new technology aerodynamically, it’s not really new in lots of sensors.
Allen Hall: Well, I look at it this way. If you turn on Formula One today and look at what the new generation of cars running around as you look at the, that front. Yes. Uh. Fin. Yeah. What do I call it? Air foil shape in the front. It’s super complicated.
Nicholas Gaudern: The sculpting of the [00:18:00] surfaces is really impressive,
Allen Hall: right? There’s a lot of thought going into those surfaces versus you turn on a Formula One race or go on YouTube and look at a Formula One race from the 1980s.
Yeah, it’s basically a piece.
Nicholas Gaudern: Yeah.
Allen Hall: To provide down downforce. That’s it. The aerodynamics wasn’t really there, so we come a long way and a lot of that technology that happens in Formula One that happens in aviation eventually rolls down into. Yeah. Wind.
Nicholas Gaudern: Exactly
Allen Hall: right. So we, we, although we are not designing Formula One style blaze today, we’re taking that same knowledge and information and we’re applying that back in.
Nicholas Gaudern: Yeah. We’re
Allen Hall: secondarily we,
Nicholas Gaudern: which is a right thing to do. We’re taking, taking inspiration from all these different aerodynamic fields and, you know, picking the best
Allen Hall: Yes.
Nicholas Gaudern: From what’s available and just allowing ourselves to be a little bit more creative.
Allen Hall: Yes.
Nicholas Gaudern: And thinking outside the box a bit. There’s so many ways to do this as we’ve been saying.
And the import. And the
Allen Hall: data’s there.
Nicholas Gaudern: The data’s there. Exactly.
Allen Hall: The data’s there because you’ve been at the DTU Yep. Uh, wind Tunnel, which also has the acoustic piece to it. Yeah. So you have measured data from a reliable source. [00:19:00] You have field data, and you know, you put all these together, you’re gonna get that improvement back.
You’re gonna get your invest back, you’ll be more profitable.
Nicholas Gaudern: So Dragon Scale, focus on the AP. And that a EP will, uh, vary depending on the turbine.
Allen Hall: Sure.
Nicholas Gaudern: But we’ll assess the turbine and, and decide the best configuration, and then say silent edge. That’s the focus on the noise reduction. And we’re seeing up to five decibels OASP on the field.
It’s, which
Allen Hall: is crazy.
Nicholas Gaudern: It’s even more That’s really good that we were hoping for, you know?
Allen Hall: Yeah.
Nicholas Gaudern: So we, we know this is gonna be a, a great product.
Allen Hall: It looks very interesting.
Nicholas Gaudern: It does.
Allen Hall: It does it. It looks complicated and you think air airflow is complicated. It’s a compressible fluid. It’s not easy to, to just assume it’s gonna do what you think it is.
Yeah. You need to get into the tunnel. You need to replicate, you need to do all that work, which is expensive in time consuming. That’s why you go to someone like Power. Curver knows what they’re doing in the wind tunnel, knows how to measure those things and know when they’re getting nonsense. Out of their computer.
I
Nicholas Gaudern: mean, you, you’ll pay thousands and thousands of [00:20:00] Euros dollars a day to run a wind tunnel.
Allen Hall: You will.
Nicholas Gaudern: You’ve gotta Absolutely. You’ve gotta turn up with your plan in hand, that’s for sure.
Allen Hall: Oh, oh yeah, yeah, yeah. And I think there’s a lot of assumptions because it, aerodynamics is hard. You know, you watch these blade spin around, you don’t realize how complicated these devices are.
They are complicated. Those air force shapes we are running today have been through a lot of history, a lot of history to get to where we are now. Now we’re just gonna take him into the next generation. This, we’re bringing ’em into the two thousands. In sort of a
Nicholas Gaudern: sense, what I’m hoping to see is, you know, with the OEMs, some OEMs do it already, but it’s important to think about these components when you’re designing new blades as well, you should because then that will allow you a much bigger design space to work in.
And
Allen Hall: a lot less customer complaints.
Nicholas Gaudern: Yes.
Allen Hall: Where’s my power?
Nicholas Gaudern: Exactly. You know, these products, particularly the VGs, are really important tools for PowerCurve robustness. And some OEMs have known this for a long, long time.
Allen Hall: Yep.
Nicholas Gaudern: And you’ll see VGs on most of their blades. Mm-hmm. Others not so much. And that’s a design choice.
It’s a design philosophy. Um, and I think it may not [00:21:00] be the right one, you know?
Allen Hall: Well, I think the operators are asking to get the most out of their turbines. Yeah. Why shouldn’t they? They should be asking for that.
Nicholas Gaudern: I think for a, for a long time, and it’s not just in wind devices, like these have been considered, you know, band-aids fixes when you’ve, you’ve messed something up.
But I feel that’s a really negative way to think about products like this. They’re doing something that the kind of raw air fall shape on its own cannot achieve. Sure. Oh no. Right. You know, you might be able to mold some interesting stuff. Uh, as part of the blade, it’s very difficult to, to recreate the kind of aerodynamic effects that these products, uh, have.
Allen Hall: Right.
Nicholas Gaudern: So they shouldn’t be considered bandaids or fixes. No. They should be considered opportunities. And ways that you can maximize performance and unlock areas of the design space that previously weren’t accessible to.
Allen Hall: Sure. Every possible component that deals with fluid air is moving this way.
Nicholas Gaudern: Yes.
Allen Hall: Jet engines, you look at jet engine, how much more is going into those jet engines today in terms of this kind of [00:22:00] technology?
Yeah. All the race colors, doesn’t matter what class, where it is, is all looking at this anything to do with aircraft, it’s all over this.
Nicholas Gaudern: Yeah,
Allen Hall: exactly. Or, or doing this today. It’s just wind that’s behind
Nicholas Gaudern: wind. Wind is
Allen Hall: significantly
Nicholas Gaudern: behind. No,
Allen Hall: it’s not magic. It’s proven technology. It’s
Nicholas Gaudern: just good engineering.
Allen Hall: Well, it’s good engineering and if you call PowerCurve, they’re gonna help you under to to, to understand what you have today and what you could have tomorrow.
Nicholas Gaudern: Yes.
Allen Hall: And how this, these devices will improve your revenue stream.
Nicholas Gaudern: Exactly. You know, we will look at your blades, we’ll give you some good advice and maybe that advice will be that.
You know, a certain product isn’t right for your blade. Right. That’s fine.
Allen Hall: That’s an answer.
Nicholas Gaudern: That’s an answer.
Allen Hall: Yeah, it is.
Nicholas Gaudern: But let’s, let’s look at the blade. Let’s see what’s possible, and let’s just have a, have a proper conversation about it over some real data, some real
Allen Hall: facts. Right. I think that’s the key, and a lot of operators are afraid to talk about aerodynamics is it’s, it’s a difficult area to, to start the conversation on, right?
Yeah. But I think at the end of the day, when I work with PowerCurve, and I’ve worked with you guys for a [00:23:00] number of years, the answers I get back are intelligent and they’re not. Super complicated. This is what you’re gonna see. This is the improvement. And then we can, this is how we’re going to show you can get that improvement.
It’s not magic,
Nicholas Gaudern: no
Allen Hall: power crews backing up with data, which I think is the key, right? Because you’re the, you do hear a lot of noise in this industry about magical products that’ll do all these things. Particularly aerodynamic ones. Yes. PowerCurves, the ones really bringing the data.
Nicholas Gaudern: Yeah. And we have, we have the track record now.
We have like we do 17, 1800 turbines. Should be over 2000 very soon with our products on. Yeah. So we have a lot, we have a lot of data to draw on to know that we’re doing a good thing.
Allen Hall: Well, and speaking of that, because one of the questions that always pops up is, well, we have put these new VGs or trailing edges on, are they gonna stay on?
How durable are they?
Nicholas Gaudern: Yeah. And that’s a, that’s a really important question to ask was it doesn’t matter how fancy aerodynamic product is, if it falls off the blade.
Allen Hall: Right.
Nicholas Gaudern: So, you know, we’ve spent a lot of, uh, time and effort looking at how we should be fixing these products on. [00:24:00] So we use a, uh, a wet adhesive.
We specify a plexus adhesive to put our products in place. Really good adhesive. It’s a great adhesive and it means that they are not going anywhere. Basically. It’s a very, uh, forgiving adhesive. Uh, and it’s a very high spec. So we, we don’t use, uh, sided tape. We might have some of our products for some initial tack to help, you know, get the clear, the clear outta the line exactly.
But in terms of the bond itself, that is with a, a proper structural adhesive. So one thing that we are really proud of is that we haven’t got any, uh, reported failures of our panels over all the installations we’ve made. And that’s a combination of materials, but also geometry, work, instructions, adhesive.
It’s, it’s the full package. So it’s something that, um, yes, say we’re very proud of. And I think it’s, it’s a big part of what we do at PowerCurve, making sure the product is the right shape. Sure. But also making sure it stays on the blade.
Allen Hall: Well, you see it [00:25:00] from OEMs who have all kinds of aerodynamic treatments on there, and they’ll double set a tape to the blade, and then those parts are on the ground.
Nicholas Gaudern: Yeah. And double-sided tape. You can get some really nice spec tape. Sure.
Allen Hall: You,
Nicholas Gaudern: yeah. But it’s not
a
Allen Hall: 20 year device.
Nicholas Gaudern: No. And the installation tolerance required on surface prep is really, really high. So it’s possible. It’s just harder. I think it’s riskier,
Allen Hall: it’s risky.
Nicholas Gaudern: So, you know, I think for us, the adhesive is, is the way to go.
And, and it’s been proven out by the, by the track record.
Allen Hall: And some of the things we’ve seen over in Australia is when trailing ulcerations have come off, it’s been a safety concern. So now you got
Nicholas Gaudern: absolutely
Allen Hall: government officials involved in safety because parts are coming up. Turbine.
Nicholas Gaudern: Yeah.
Allen Hall: You
Nicholas Gaudern: can’t have these components flying, flying through the air.
That’s, that’s not safe.
Allen Hall: That’s because PowerCurve has done the homework.
Nicholas Gaudern: Yes.
Allen Hall: And has the track record. That’s why you wanna choose PowerCurve. So how do people get a hold of PowerCurve? How do they get a hold of you, Nicholas, to start the process?
Nicholas Gaudern: So, um, you’re welcome to reach out to us in lots of different ways.
We’re on LinkedIn. Uh, we have our website, [00:26:00] PowerCurve, dk, um, so yeah, LinkedIn websites. There’ll probably some links on this podcast as well to get in touch. But, um, yeah, whatever way works best for you.
Allen Hall: Yeah, it’s gonna be a busy season. So if you’re interested in doing anything with PowerCurve this year, you need to get on the website, get ahold of Nicholas.
And get started, uh, because now’s the time to maximize your revenue.
Nicholas Gaudern: Thanks a lot and great to talk to you,
Allen Hall: Nicholas. Thanks so much for being back on the podcast.
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