Hello every one,
I tried to simulate the turbine and in a post CFX I noticed that the torque value is negative (-0.2 [Nm]). However, I looked at CFX tutorial and in "Chapter 17: multiphase flow in a mixing vessel" the torque value is -67.4 [N.m] and multiplying by -4 to find the torque required by all of the impeller blades. Why it is multiplying by -4 instead of 4?
Therefore, can I say that my simulation is correct and because I have 4 blades, total torque would be (-4*-0.2=0.8Nm) and P=T*w so P=(0.8*3000=240 W) because otherwise P=-0.8*3000=-240W that means the turbine instead of producing power, it needs power.