Rotate and Power/Torque

devanshchoksi · February 8, 2021, 01:16

I have designed a turbine with similar characteristics to a wind turbine. I am trying to achieve the following:
1. rotate the turbine from the air that is hitting it
2. Calculate power/torque

FliegenderZirkus · February 8, 2021, 03:07

I think that what you describe can be done using the 6DOF solver, but it would be a very difficult and expensive simulation (I've never done that so I can't help further). A more pragmatic approach is to prescribe the angular velocity and measure th quantities of interest (e.g.torque). Of course, the rotation speed is unknown at this point so you have to calculate many operating points and effectively construct the characteristics of the turbine. You can then interpolate between the calculated points (outside of cfd).

devanshchoksi · February 8, 2021, 03:20

Quote:

Originally Posted by FliegenderZirkus

I think that what you describe can be done using the 6DOF solver, but it would be a very difficult and expensive simulation (I've never done that so I can't help further). A more pragmatic approach is to prescribe the angular velocity and measure th quantities of interest (e.g.torque). Of course, the rotation speed is unknown at this point so you have to calculate many operating points and effectively construct the characteristics of the turbine. You can then interpolate between the calculated points (outside of cfd).

I have the details i.e. the speed at which the air will hit the turbine, just need to find a way to show that it is a rotating body. I have gone for the general approach which is to create an enclosure, boolean then creating named selection (defining the inlet and outlet points).
And I am using Fluent, is this sought of analysis done in fluent or CFX?
which one is better?
thank you

FliegenderZirkus · February 8, 2021, 03:27

If you decide to use the approach I suggested, then both Fluent and CFX are fine. You will need to create a cylindrical domain around the turbine and apply a rotating reference frame. There are tutorials on this, try looking for "MRF".

Yasser · February 8, 2021, 15:45

Not only SDOF. You can use CG_Motion as well.

Calculate the moment around the axis of rotation, then apply Newton's second law to solve for the new rotational velocity and provide it to the solver.

February 8, 2021, 01:16	Rotate and Power/Torque	#1
devanshchoksi New Member devansh Join Date: Feb 2021 Posts: 3 Rep Power: 5	I have designed a turbine with similar characteristics to a wind turbine. I am trying to achieve the following: 1. rotate the turbine from the air that is hitting it 2. Calculate power/torque

February 8, 2021, 03:27		#4
FliegenderZirkus Member Join Date: Nov 2019 Posts: 98 Rep Power: 7	If you decide to use the approach I suggested, then both Fluent and CFX are fine. You will need to create a cylindrical domain around the turbine and apply a rotating reference frame. There are tutorials on this, try looking for "MRF". devanshchoksi likes this.

February 8, 2021, 03:07		#2
FliegenderZirkus Member Join Date: Nov 2019 Posts: 98 Rep Power: 7	I think that what you describe can be done using the 6DOF solver, but it would be a very difficult and expensive simulation (I've never done that so I can't help further). A more pragmatic approach is to prescribe the angular velocity and measure th quantities of interest (e.g.torque). Of course, the rotation speed is unknown at this point so you have to calculate many operating points and effectively construct the characteristics of the turbine. You can then interpolate between the calculated points (outside of cfd).

February 8, 2021, 15:45		#5
Yasser Member Yasser Selima Join Date: Mar 2009 Location: Canada Posts: 51 Rep Power: 19	Not only SDOF. You can use CG_Motion as well. Calculate the moment around the axis of rotation, then apply Newton's second law to solve for the new rotational velocity and provide it to the solver.