Linear model responses in forced flow cooling

• A fast, agile code to evaluate the temperature map in structures during machine commissioning and operation is presented. • The code can solve systems of differential and algebraic equations via modern numerical methods (e.g. finite volumes). • It significantly reduced CPU runtime compared to FEM codes (e.g. ANSYS) and allows detailed refinement of solid geometry and fluid flow structure. • The attention is focussed on the ITER vacuum vessel temperature field during plasma burn and baking. • Future development may include semi-analytic local solutions for cross-section while maintaining fast execution. The aim of this paper is to present a fast method capable of computing thermo-hydraulic transients in solid components that are cooled (or heated) by incompressible forced flow with or without external heating sources. By coupling the heat conduction equation in the solid volume to the heat transfer to the forced flow we derive a linearized mapping between the vector of input (control) quantities u (t) such as mass flow and inlet temperature to the vector of nodal temperature T (t) in the solid domain. A comparison between the newly developed code, which is finite volume based and a standard finite element-based code such as ANSYS is presented. Despite the significant reduction in CPU time, the finite-volume code well approximates the solid temperature field computed by ANSYS for the two cases considered here, i.e. the fusion power operation and vacuum vessel baking operation.