/sci/ - Science & Math

[Anonymous No.15080192]

What is the optimal geometric shape of a wind turbine which generates as much electricity as physically possible? Have engineers actually designed the blades of a wind turbine so accurately that even if they were one millimeter wider or narrower, shorter or longer, the turbine could no longer generate as much energy as it used to?

I would imagine intuitively that the blades should be wider to capture more wind.

[Anonymous No.15080215]

>>15080192
I'm really not sure why the fan blade type is so much more common than vertical cylinders that can catch wind from any direction.

[Anonymous No.15080219]

>>15080215
Because it's more efficient at killing birds.

[Anonymous No.15080221]

>>15080192
they're built like that to cut down on construction costs rather than maximize power output. if you wanted a bird&bat chopper that captured more power then you'd need a stronger tower & everything else to go with it. it'd probably be a lot cheaper to just buy two shitty mass produced ones than reinvent the wheel and build a perfect one.
you might be able to think up a better one, but you'll never built it. meanwhile the crap one gets built over an over again, so whomever designed the crap one seems to know how to get things done better than you do.

[Anonymous No.15080226]

>>15080219
Just like Mr. Burns' recycling...

[Anonymous No.15080227]

>>15080221
At least OP knows how to start a decent discussion, while all you will ever do is be negative.

[Anonymous No.15080233]

>>15080221
It is still a problem of maximizing power output. Construction cost is simply a new variable in the equation. You need to maximize power output given the money you have available for the construction project.

[Anonymous No.15080240]

>>15080215
>>15080219
Gotta get all those tendies somehow!

[Anonymous No.15080852]

>>15080192
Windmills currently get about 4/5th's the Betz Limit in windmill efficiency. Too many factors change efficiency to really figure out exactly how close we can get to that limit. High wind areas may benefit more from narrower blades and low wind areas may be the opposite etc. Testing billions of designs in a wind tunnel wouldn't really be that useful. We could coat the whole thing in teflon too at huge cost and it might churn out a non negligible higher amount of efficiency. I don't think anyone is seriously putting much effort into blade geometric shape R&D right now since there's not much ROI anymore. They're good enough. Finding cheaper manufacturing and delivery methods is a much more lucrative investment.
https://en.wikipedia.org/wiki/Betz%27s_law

[Anonymous No.15081135]

>>15080192
What counts is the swept area, NOT the blade area.
The blade shape is a compromise of length and strength. Longer blades increase swet area and power generated, while also increases bending moment near the hub. And at the same time the blades must handle te turbulent wind near the ground.

[Anonymous No.15081445]

>>15080852
We already have a fair idea where the losses are.
With 160 m long blades, the circumference is close to 1 km. Thus the rotor must take more than 3 seconds to stay below the sound barrier. That makes for too low RM for the generator, so you need gearing. To save weight they use a planetary gear, but that has at best 3 percent power loss. So a modern 15 MW turbine loses about 500 kW in the gear alone and that needs actve oil cooling and that takes even more power. In case of power failure you need an UPS to keep the oil cold until the main rotor winds down. If any of this fails, the heat will quickly pass the flash point and you have an uncontrollable fire in the nacelle.

The the generator needs cooling. Just a 1 percent loss in conversion mechanical to electrical power is 150 kW. So add more active cooling hear. Bearings are plentifu, need lubrication, and an oil circuit with filter and cooling.

You also have a yaw motor and often motors for regulating the pitch of the blades. This requires a computer control system that needs power.

Last but not least, you need a transformer to transform up to line power, with frequency controller. This is usually places at the base of the tower so you can afford heavier and more efficient equipment here say 1 percent loss, which is 150 kW. Add some cooling to this, and this reaches 200 kW quickly.

People underestimate the enormous complexities and therefore the losses incurred. A nacelle on a modern wind tornine is now in excess of 300 - three hundred - tons.

[Anonymous No.15081658]

>>15080227
If thats the case, why did you choose to give a critical reply to "the guy who is always negative" instead of going out of your way to compliment OP? choosing the focus on the negative rather than the positive?
On the topic of positive developments, fully functioning, mass produced wind power gear already exists, its already been designed and built, so nobody need to go through those costly stages to get wind power anymore, you can just buy wind power off the rack, its cheap and effective, what a bargain! YAY!
high IQ ppl should have no trouble thinking up something else useful to do instead of wasting their precious, special genius brains by banging their heads against the wall on a problem thats already taken care of. what a bonus if we could have wind power plus a bunch of other bigbrain stuff that nobody has imagined yet and which only bigbrains can think up and that we will never get if the bigbrains are all too busy instead thinking about how to get slightly more kilowatts per dollar on wind power.

[Anonymous No.15081786]

>>15080233
The calculations I have seen, relate to cost across the entire life tme of the installation and includes everything from building to demolition plus service in the years between these. Investors care about return n investment, not construction cost.

[Anonymous No.15081981]

>>15081658
>more negativity

I did compliment OP and contributed to the thread.

You're telling people not to try to improve an existing technology, probably because you're an energy shill.

Clearly, the vertical cylinder type wind turbines have a lot of advantages, and the only reason anyone in this thread can think of their lesser use is because people like you want to keep chopping birds.

[Anonymous No.15082002]

>>15080192
>What is the optimal geometric shape
cube, ready to be recycled

[Anonymous No.15082025]

>>15080192
>What is the optimal geometric shape of a wind turbine
cut down, dismantled and ground into dust

[Anonymous No.15082060]

>>15081445
That's all true but OP was asking about blade geometry and its effects on efficiency not the parasitic losses/loads throughout the system itself.

[Anonymous No.15082079]

>>15080192
this shape seems to be the most efficient at generating power

[Anonymous No.15082176]

>>15080192
I don't know much about wind turbines, but as far as I know we haven't reached the optimal design on anything that has to do with fluids. That includes car engines, jet engines, the shape of cars and jets that makes them as aerodynamic as possible and so on. Fluid dynamics is a complex field where we can only get an approximate solution numerically and with a lot of computing power. Computational Fluid Dynamics (CFD), which seeks ways to improve our ability to solve those complex problems numerically, is currently an active area of research and as the numerical algorithms improve the designs should improve and get closer to the optimum. But the fuck do I know.

[Anonymous No.15083113]

>>15082060
If you restrict the entire discussionto the blade geometry, you have the problem of making sure the blades don't crack under their own weight. The speciic details are trade secrets, and also a reason why the wind turbine makers prefer the blades destroyed after use and not handed over to third parties for reuse that could be industrial espionage.

Cost is important too, which is why glass fiber is mostly used. They will soon be forced to use carbon fibres, and I would expect nanotube composites to come up next. Presently they are struggling to get much beyond 15 MW, and a few articles of 16 - 20 MW seem more like advertising and hope than genuine offers.

[Anonymous No.15084928]

>>15081445
>If any of this fails, the heat will quickly pass the flash point and you have an uncontrollable fire in the nacelle.
What if you just use metal gears? How do you have fire with metal?

[Anonymous No.15085703]

>>15084928
Metal without lubrication? That will take a breakthrough, especially for the enormous forces involved.
You are still facing a cooling problem, and metal can become very hot just by mechanical forces. Dumping 500 kW into 10 tons of metal gears will inevitably go wrong.

[Anonymous No.15087274]

>>15085703
Why can't you cool them with water or something?

[Anonymous No.15087308]

>>15083113
>you have the problem of making sure the blades don't crack under their own weight
What if you used a metal alloy with the highest possible tensile strength. Or even exotic materials like carbon fiber or something similar. Engineers would come up with something.

[Anonymous No.15087730]

>>15087274
Water or oil, sure, but then you are back to the original problem of dissipating substantial amounts of heat.

>>15087308
>What if you used a metal alloy with the highest possible tensile strength.
Metals and alloys typically suffer form fatigue and then failure. This is why composites are used.
>Or even exotic materials like carbon fiber or something similar.
Carbon fiber can be used in composites, sure. The problem is a cost far greater than for glass fiber reinfored composites. To get anywhere beyond 20 MW my guess is that they will have to look at carbon fiber. One advantage is that it would simplify recycling the blades, at least as fuel.
>Engineers would come up with something.
No doubt they are looking at this, otherwise wind power would be stuck at 15 MW. There is an economy of scale that makes huge wind turbines more cost effective, in spite of the enormous complexity.

[Anonymous No.15087742]

>>15080192
I have a better Idea, ok get, get this, we send these wind turbines into space, right, and then we, get this, we then turn them towards the sun. Then we capture the energy from solar winds, which have gigawats more of energy than regular winds

[Anonymous No.15088986]

>>15087742
Electricity prices here increasd 20x, at this rate solar power satellites will soon be commercially viable.