[khadija8]

Hello,
I am working on the numerical simulation with Ansys Fluent of a 3D GORLOV water turbine in two-phase flow (VOF method) and unsteady state.
I had problems with the simulation, is it possible to ask you some questions
thanks
Question 1: Do I have to set the turbine rotation speed at the start of the simulation or when the water strike the turbine? At the start of calculation, the rotor rotates with the air before the jet of water strikes it ?
Question 2: After a few seconds of calculation, the water does not enter the rotating domain to turn the turbine; I do not know what the problem is.
Question 3: I made another example with the savonius turbine; do the relaxation factors have an effect on the calculation?
- Cas 1: with the following relaxation factors
After the calculation, I obtained the following volume faction contour; the water does not enter the rotating domain
- Cas 2: with the following relaxation factors
After the calculation, I obtained the following volume faction contour, but I got unrealistic values of epsilon and k
Question 4: After the computations, the average Monitors value I got was a negative value. This would suggest a negative torque value that is clearly wrong; I do not know the exact reason for this. I am getting negative moment values when I put moment center as (0 0 0) and moment axis as (0 0 1). However, I get the positive moment when I put (0 0 -1) direction that is clearly wrong.
Question 5: Does the direction of water flow affect the moment coefficients?

[khadija8]

Question 4: After the computations, the average Monitors value I got was a negative value. This would suggest a negative torque value that is clearly wrong; I do not know the exact reason for this. I am getting negative moment values when I put moment center as (0 0 0) and moment axis as (0 0 1). However, I get the positive moment when I put (0 0 -1) direction that is clearly wrong.