Numerical experiments on helium flow in superconducting generators

The authors report on numerical experiments on helium flow patterns in a superconducting generator. This was done with a thermohydraulic analysis program which integrates the equations of motion for one dimensional coolant mass flow rates in a rotating channel network. The method includes frictional, buoyant and inertial forces. Heat generation and transfer as well as thermophysical material properties are modelled realistically. As a result, a complete picture of the hydraulic and thermodynamic state in the cooling system during transients is obtained. For the KWU/Siemens Test Rotor, a simplified five channel model including rotating supply bath and self-pumping exhaust system is investigated. A number of unexpected flow patterns are detected and explained