[Hkn]

Hi users,

I am working to simulate a vertical axis wind turbine. I am using transient rotor stator condition in analysis. I want to make my analysis, I want to take the wind the velocity of rotation of on the rotating shaft. I mean, I don't want to give this value manually, this value is take the wind velocity. I researched this a lot but could not find anything specific. I know can this using expression in CFX but which can I write expression?

Can you help me about this issue or can you who have sent me a sample analysis?

my mail adress hakan.cosanay@gmail.com

Thank you all.

[ghorrocks]

I do not understand your question. Are you asking how you set the far-field wind velocity? Or how to you measure the air velocity inside the structure?

[Hkn]

Thanks your reply Ghorrocks,

I mean I value the angular velocity (rev/min) of the rotating blades, I want to take the wind and I want to measure the value of the torque (on the shaft) from the wind speed.

[ghorrocks]

If you simulate a rpm and wind speed you will get a torque. If you do a range of rpms then you will find the point where the rotor torque equals the system torque. This will be the device steady state speed at these conditions.

I do not recommend trying to find the rotor speed in a single simulation. This is quite a tricky simulation so is not recommended.

[Hkn]

I understood Ghorrocks. I don't know exactly what to do. I can run the analysis by manual values (angular velocity) but I could not get the angular velocity set the value of the wind speed.
I am try similation, like this. Turbine acceleration is I want to be sourced from the wind but I stil fail. Plase help me.

https://www.youtube.com/watch?v=nj_iL8PXOD8

Thank you.

[ghorrocks]

The approach I describe gives you the system curve, that is the net torque on the system at various rotation speeds. Once you know the system curve you can get system acceleration as well as you know the net torque and the system inertia.

[Hkn]

Thank you so much Ghorrocks, actually my annoyance's starting at exactly this point. e.g. ıf we have system curve (I think system curve is torque/revelations chart of generator) how it's describe in cfx ? Realy I am need exactly this issue. It is my last questions

If you have ex. analysis or document this point do you send me?

[ghorrocks]

CFX will give you a series of torque points against speed. If you want the system acceleration then write a simple ODE solver and integrate over time to give you the system response. A simple little ODE solver can be written in excel easily, but a proper mathematical package like matlab or python/numpy is much better.

Sorry, I don't have a tutorial I can send you.

[Hkn]

Thank you ghorrocks.