Hello!
I am doing some CFD simulations on the housing of a radial piston hydraulic motor (the simplified geometry can somewhat be similar to a gear spinning in a confined volume where the cogs are replaced with interior walls pushing oil around in the house). The time-dependent solution converges, both for laminar and turbulent flow (k-eps) and give a relatively accurate result regarding the torque asserted from the fluid on the surrounding walls when compared with experimental data. The problem arises when I look at the pressure, which fluctuates with a local minimum value of -2900kPa. As inlet condition to the model I have specified a velocity, and as outlet a pressure (0 Pa). The reference pressure is 1 atm. I know there will be cavitation in the motor so low local pressures are expected (down to -1 atm) , but these values seem extreme and impossible. Does anyone have some tips regarding how I can deal with these extreme values and produce a more accurate result regarding the pressures?
I am doing some CFD simulations on the housing of a radial piston hydraulic motor (the simplified geometry can somewhat be similar to a gear spinning in a confined volume where the cogs are replaced with interior walls pushing oil around in the house). The time-dependent solution converges, both for laminar and turbulent flow (k-eps) and give a relatively accurate result regarding the torque asserted from the fluid on the surrounding walls when compared with experimental data. The problem arises when I look at the pressure, which fluctuates with a local minimum value of -2900kPa. As inlet condition to the model I have specified a velocity, and as outlet a pressure (0 Pa). The reference pressure is 1 atm. I know there will be cavitation in the motor so low local pressures are expected (down to -1 atm) , but these values seem extreme and impossible. Does anyone have some tips regarding how I can deal with these extreme values and produce a more accurate result regarding the pressures?