[innvah]

Hi,

I am currently running a steadyState MRF case with a turbine in OpenFOAM 6. I am trying to evaluate the behavior of torque/moment output for different RPM values (defined in MRFProperties) to create a RPM-torque table.

Why do I get the same output torque for different turbine geometries with constant RPM and inlet flow? The case set-up is identical, the only thing that have changed is the number of blades on the turbine.


Is there something I've missed? Thanks for responses in advance!

[Lookid]

Hello,

Did you properly define the patches where you calculate the forces/moment in controlDict?

libs
(
"libforces.so" // this is for forces
);

functions
{
    forces{
	type forces;
	functionObjectLibs ("libforces.so");
	patches (BLADE HUB SHROUD); // sum the forces and moments on those patches
	writeControl timeStep;
	writeInterval 1;
	p	p;
	U	U;
	log true;
	rhoInf 1000;
	rho rhoInf;
	CofR (0 0 0); //centreOfRotation
	}
}

Is the MRF zone well defined?
Do you control other parameters to see if the simulation is proper? (does the head, efficiency changes with the flowrate for example)