||February 26, 2010 02:04
Turbomachinery issues again, Pressure overprediction
I was looking for some turbo advice. I had earlier posted about my 3 stage axial turbine model that was initally overpredicted massflow. Well I managed to correct this by refining the mesh extensively. Now the odd thing is the pressure at various measurement points do not change much when compared to coarses discretizations. Both, compared to experimentally are strongly overpredicted, yet the massflow for most cases are within 2% and the total to static efficiency is within 1.5 % when compared to experiment. I cannot understand this, I would have thought the pressures would be a little closer to experimental results, if other parameters are closer. It seems all the pressures when compared to experiment are offset by a certain value that slighty increase as the point moves axially. I have even tried two different turbulence models a 2 equation and a RSM model yet the pressures are still overpredicted. Any thoughts anyone?