A new kind of wind turbine

[RevI]

I am an Indian inventor. For a long time, I am continuing personal research about a new kind of wind power generation system. Recently, while searching net, I have found out that the necessary machinery is already available in market. In short, the machine now can be built easily.
At present, I have completed the CAD drawing and done some ANSYS simulation testing. As per the latest simulation where the RPM was set of 3600, the torque was found to be around 1.52 Newton-Meter for a machine of 35 cm diameter and the input wind velocity was set to be 6 m/s. For me, this is promising result and I can say that no wind turbine in anywhere around the world of that little diameter can generate such torque at this RPM.

I want to know how close a real prototype of similar parameters can perform in comparison to the simulation.

[OceanBreeze]

If you want a detailed answer, first you will need to provide more details such as how you calculated torque and explain what makes your design “a new kind of wind power generation system”

For now, I will show a generic solution. I note that your torque of 1.52 Nm does seem impossibly high. In practice, your turbine should never achieve an RPM of 3600 with a wind speed of 6 m/s. That corresponds to a ratio of blade tip speed to wind speed of 11. That is higher than the optimum ratio of 7.   

At a ratio of 11 the turbine performance falls off due to excessive turbulence in the wind stream, among other degrading factors.

In general, the optimal rotational speed of a wind turbine rises with wind speed, falls with the length of the blades, and falls with number of blades.

With a ratio of 7, (blade tip’s speed divided by the wind speed), the RPM drops to about 2290. Actually, the torque should be better at this lower level of RPM. However, remember the Betz limit on efficiency is 59.3%.

Torque drops to an estimated value of 0.3705 Nm according to this simplified example calculation based on your given parameters:

Blade Area = π * (Blade Radius)^2

Blade Diameter = 35 cm,    Blade Radius = 17.5 cm = 0.175 m

Blade Area = π * (0.175 m)^2 = 0.096 m²

The force exerted by the wind on the turbine blades can be calculated using the formula:

 Wind Force = 0.5 * Air Density * Wind Speed² * Blade Area

Using a standard air density of 1.225 kg/m³

Wind Force = 0.5 * 1.225 kg/m³ * (6 m/s)² * 0.096 m²

             =  2.117 N

The torque generated by the turbine can be calculated by multiplying the wind force by the radius of the turbine.

Torque = Wind Force * Turbine Radius  = 2.117N * 0.175 m  = 0.3705 N·m

[RevI]

1 hour ago, OceanBreeze said:

If you want a detailed answer, first you will need to provide more details such as how you calculated torque and explain what makes your design “a new kind of wind power generation system”

 

For now, I will show a generic solution. I note that your torque of 1.52 Nm does seem impossibly high. In practice, your turbine should never achieve an RPM of 3600 with a wind speed of 6 m/s. That corresponds to a ratio of blade tip speed to wind speed of 11. That is higher than the optimum ratio of 7.   

 

At a ratio of 11 the turbine performance falls off due to excessive turbulence in the wind stream, among other degrading factors.

 

In general, the optimal rotational speed of a wind turbine rises with wind speed, falls with the length of the blades, and falls with number of blades.

 

With a ratio of 7, (blade tip’s speed divided by the wind speed), the RPM drops to about 2290. Actually, the torque should be better at this lower level of RPM. However, remember the Betz limit on efficiency is 59.3%.

Torque drops to an estimated value of 0.3705 Nm according to this simplified example calculation based on your given parameters:

 

Blade Area = π * (Blade Radius)^2

 

Blade Diameter = 35 cm,    Blade Radius = 17.5 cm = 0.175 m

 

Blade Area = π * (0.175 m)^2 = 0.096 m²

 

The force exerted by the wind on the turbine blades can be calculated using the formula:

 

 Wind Force = 0.5 * Air Density * Wind Speed² * Blade Area

 

Using a standard air density of 1.225 kg/m³

 

Wind Force = 0.5 * 1.225 kg/m³ * (6 m/s)² * 0.096 m²

 

             =  2.117 N

 

The torque generated by the turbine can be calculated by multiplying the wind force by the radius of the turbine.

 

Torque = Wind Force * Turbine Radius  = 2.117N * 0.175 m  = 0.3705 N·m

The torque that you have calculated, is based on a common market available type wind turbine and my turbine is different and that's why it's a "new kind". It's a concentrated wind turbine type and that's why able to generate that high amount of torque even with such medium wind speed of 6 m/s. ANSYS has been used for a long time to understand the behavior of wind turbines of various kinds and it can't make such a big mistake. I think you better have some clear idea about my design and then come to conclusion. And again, it's a new kind and that's why it can generate that high amount of torque.

Edited December 29, 2023 by RevI

[Hydro]

It’s interesting.
But first you would show a diagrams of the turbine design or at least ANSYS-diagrams.
How can you discuss something that is not visible? 

[RevI]

28 minutes ago, Hydro said:

It’s interesting.
But first you would show a diagrams of the turbine design or at least ANSYS-diagrams.
How can you discuss something that is not visible? 

I can, but only to those who are interested. if you are interested, then I can share the report with you privately.

[Hydro]

Yes, sure. 

Thanks a lot. 

Edited December 30, 2023 by Hydro

[RevI]

The is site is problematic. Responding very slow. By the way, are you an wind power enthusiast?

[Hydro]

I am a wind and hydropower enthusiast

[OceanBreeze]

1 hour ago, Hydro said:

It’s interesting.
But first you would show a diagrams of the turbine design or at least ANSYS-diagrams.
How can you discuss something that is not visible? 

That is why my first comment was "If you want a detailed answer, first you will need to provide more details such as how you calculated torque and explain what makes your design “a new kind of wind power generation system”.

Also, I believe the physics equations of wind power are independent of any possible turbine design. The torque being claimed, 1.52 Nm, is much too high for a wind speed of 6 m/s confined to an area of 0.096 m^2, regardless of any new design, in my opinion.

I need to see the calculations that were done and if possible some information about the design.

[RevI]

1 hour ago, Hydro said:

I am a wind and hydropower enthusiast

This site is a hell to work with. Unbelievably slow.

[OceanBreeze]

I still have not seen any ANSYS data for this WT.

I have found this very interesting article which supports my own calculations of a concentrated WT (not the simplified calculations I posted earlier of a generic Horizontal axis WT (HAWT).

Using a concentration factor of 1.25 the max value of torque I can come up with is only about 1 Nm , still lower than the 1.52 that is being claimed.

I suspect that the ANSYS simulation did not fully take into account the turbulent resistance that builds up in the concentrator, forcing most of the free stream wind to flow around the concentrator, instead of through it.

That is only one factor that I am in disagreement with, but my opinion and calculations cannot be confirmed without a real-world test of a working model.

[RevI]

10 minutes ago, OceanBreeze said:

I suspect that the ANSYS simulation did not fully take into account the turbulent resistance that builds up in the concentrator, forcing most of the free stream wind to flow around the concentrator, instead of through it.

It's not a big problem. It can be easily overcome by adding adding simple thin cylindrical rim around the entry. That will obstruct the air to pass by and will force the flow through the cone.

And, here are some examples of concentrated wind turbines.

Video 1, Video 2, Video 3, Video 4

And, the recently installed Darwin/skegness turbines are also a good proof that how far wind concentrators can perform. What you have said is just problem and it can be easily overcome.

[Hydro]

2 hours ago, OceanBreeze said:

 

I thought that ANSYS quite accurately describes all processes, including turbulence.
Or I'm wrong ?

Edited December 31, 2023 by Hydro

[RevI]

1 hour ago, Hydro said:

thought that ANSYS quite accurately describes all processes, including turbulence.
Or I'm wrong ?

The paper suggested just a problem which can be easily solved. Not a big deal by any means. This paper suggested that in the design, a large section of the flow will pass by, but that can be easily countered.

[OceanBreeze]

6 hours ago, RevI said:

It's not a big problem. It can be easily overcome by adding adding simple thin cylindrical rim around the entry. That will obstruct the air to pass by and will force the flow through the cone.

And, here are some examples of concentrated wind turbines.

Video 1, Video 2, Video 3, Video 4

And, the recently installed Darwin/skegness turbines are also a good proof that how far wind concentrators can perform. What you have said is just problem and it can be easily overcome.

Essentially you are saying that turbulent resistance in the concentrator can be overcome by forcing even more air into the concentrator?

That just doesn't sound right to me.

In any case, I am beginning to think with a high enough concentrator efficiency factor and the ring turbine design, it may be possible to achieve a torque of 1.52 Nm . . . . .but I do not agree with the swept blade area of only 0.15 m^2 as stated in the article you linked to.

I also do not agree with some of the statements made, such as Betz efficiency can be exceeded.

As long as the windspeed is measured at the turbine blades, Betz can never be exceeded.

Using the free stream velocity to calculate turbine efficiency when there is a concentrator, is misleading, in my opinion.

Of course, if I was making and selling wind turbines I might be inclined to do the calculation that way, same as a car salesman using engine power instead of BHP to sell a car.

I don't have much more to say unless you finally get around to posting the actual calculations from ANSYS for your turbine.

[OceanBreeze]

6 hours ago, Hydro said:

I thought that ANSYS quite accurately describes all processes, including turbulence.
Or I'm wrong ?

I have no comment on the accuracy of any ANSYS simulation.

My only point is turbulence can be very difficult to quantify.

[RevI]

1 hour ago, OceanBreeze said:

also do not agree with some of the statements made, such as Betz efficiency can be exceeded.

Kindly go through this video.

1 hour ago, OceanBreeze said:

Essentially you are saying that turbulent resistance in the concentrator can be overcome by forcing even more air into the concentrator?

Air (or any kind of fluid) will always take the path of least resistance. What we need to do is forcing all the air entering into the inlet to pass through the turbine. That's not a big problem. And I want to understand is the turbulence resistance can be a dissipiative force i.e. it will cause wastage of wind energy or not. And, ANSYS has been used for long time to understand the behavior of wind turbines. And I hope while doing the simulations, the programmers certainly taking into account such factors. Otherwise, ANSYS can't be trusted widely. It seems that you just can't accept the high torque generated by such a machine.

I think you better make a small scale prototype and test everything by yourself.

Edited December 31, 2023 by RevI