An Approach to Coupled Thermal Hydraulics and Structural Mechanics Problems for the MEGAPIE Spallation Source Tqarget

This paper describes some novel heat transfer and stress analysis problems that arose in the context of demonstrating the cooling principle of a liquid-metal neutron spallation source target. The design studies using computational fluid dynamics (CFD) resulted in an optimum flow configuration being defined for the coolant circulation. Simultaneously, stresses in the structural components were examined using finite element method (FEM) techniques. Central to the coupled CFD/ FEM analysis strategy was the construction of an interface program, which enabled different specialist groups to carry out the thermal hydraulics and structural mechanics analyses using different commercial or in-house software packages within a common project, and with fully consistent model data. For the studies reported here, the commercial CFD code CFX-4 and the commercial structural analysis codes ABAQUS and ANSYS have been employed. Results for steady-state operation of the target show that the critical lower target components are adequately cooled, and that stresses and displacements are well within tolerances. Transient analysis of a beamtrip and power-up event is also described, showing that no stress crisis occurs.