Simulation of gas flow through cryogenic helium mixed-flow turbine and helium turbines in-house testing and vibration diagnostics.

1D and 3D CFD flow analyses were applied on mixed-flow helium turbine stage with impeller of 16.9 mm diameter to study its external and internal thermodynamic and aerodynamic parameters when operated with cold cryogenic helium and dry warm pressure air. Flow parameters in important flow planes inside of the turbine stage are presented. Axial force acting on the impeller is evaluated and compared with the results of simpler integral computational method. External parameters- axial force acting on the thrust bearing and cooling power - are compared. The values of Reynolds number for nozzle vanes, impeller and inlet and outlet tube are presented and compared. The 3D CFD results of variable Reynolds number are presented focusing on the nonuniformity of the flow velocity distribution and relative losses of flow kinetic energy and the influence on cooling isentropic efficiency was quantified. So, theoretical resources for creation of helium turbines in-house test stand working with dry compressed air are presented and the test stand and its functions is briefly described. Method of high speed dynamic balancing turbine rotors of operational speed up to 360 000 rpm after their manufacture and dynamic gas bearings rotor vibration diagnostics are presented and needed in-house equipment is described.