We have a rotating turbine wheel of 16mm diameter rotating at 200,000 rpm. It is an inward mixed flow (radial inlet, axial discharge) turbine. Air inlet is normally a pressure of 3-4 bar with a Mach number of 0.95 or so. Exit pressure is 1 bar and exit Mach number is expected to be between 0.3 and 0.4. The turbine is designed for inlet temperature of 122 K and exit temperature of 85K. There are 10, each blade twisted in a manner to give radial entry (relative velocity) and axial (absolute velocity) discharge. The CFD study is focusing in the flow through the turbine wheel blade passages. By using Fluent- turbulence model ( k-€ ) I am getting Mach number is more than 1 at the exit of turbine wheel. Kindly suggest me how to reduce Mach Number less than 1.

Hi,

I have a question about your question. I study also in a turbine design and search a solution for turbine bearing. Could you help me about your solution in your turbine bearing design. What kind of turbine bearing did you used.

Thanks a lot.