SIMULATION OF GAS FLOW THROUGH CRYOGENIC HELIUM MIXED-FLOW TURBINE AND HELIUM TURBINES IN-HOUSE TESTING AND VIBRATION DIAGNOSTICS

摘要

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