Simulation of a Buoyancy Influenced Forced Fluid Flow Using a Finite Volume and a Finite Element Code

New reactor designs comprise passive elements for decay heat removal. Computational-Fluid-Dynamics codes are an appropriate tool for the assessment of the efficiency of those components. Most of these codes are based either on the Finite-Volume or the Finite-Element method. Because of the importance for reactor safety these numerical tools have to be thoroughly validated using results from experimental setups.
The governing mechanism in passive components for decay heat removal is natural convection and heat transfer with internal heating. To assess the capability describing mixed convection flow, post test calculations of an IAHR benchmark exercise were performed. The commercial codes CFX-4® and ANSYS/FLOTRAN® were used, representing the Finite-Volume Method and the Finite-Element Method respectively.
This paper presents a discussion of the problems and capabilities of each code to calculate complex flow regimes and temperature fields.