Author(s)

V. Pržulj & M. Shala

Abstract

The paper reports on the use of the homogeneous multi-phase mixture modelling approach to simulate nucleate boiling in low pressure flows. A variant of the RPI (Rensselaer Polytechnic Institute) mechanistic nucleate boiling model provides closures for the wall thermal conditions and mass transfer rates due to phase change in the bulk flow. The bubble departure diameter at the wall and the bubble bulk diameter are identified as the most influential factors and their original model coefficients are modified. The numerical difficulties due to large density variations associated with phase change are successfully addressed in conjunction with the segregated pressure based SIMPLE (Semi-Implicit Method for Pressure Linked Equations) algorithm. The nucleate boiling model has been compared against published data from two experiments. The computed and measured values for the wall heat flux and vapour volume fractions are in broad agreement. The model capability is also demonstrated for the engine coolant flow where the conjugate heat transfer problem involving complex engine components is solved. Keywords: CFD, nucleate boiling, multi-phase mixture, RPI model, engine cooling.

Keywords

CFD, nucleate boiling, multi-phase mixture, RPI model, engine cooling