Unrealistic results

Manuel

Hello, I'm currently carrying out a simulation of a centrifugal water pump and results obtained so far for the head coefficient are far from realistic (about half the value of the experimental data). Data used so far: -ratational reference frame for blade passage -tethraedal mesh -200 000 cells -second order upwind -second order pressure scheme -convergence criterion:1*10-5 -k-epsilon turbulence model -under relaxation factors lowered to 0.2 for pressure and 0.5 for momentum,k and epsilon -inlet bc velocity, constant at the pipe inlet -outlet bc constant pressure at vaneless diffuser, 0 gauge

If anyone has any suggestion about what I could try or check, it would be more than welcome, thanks a lot