Subcooled boiling heat transfer modelling for internal combustion engine applications

Abstract

Any boiling-based strategy in developing cooling systems of internal combustion (IC) engines requires an accurate prediction of coolant-side heat transfer. The computational fluid dynamics (CFD) simulation incorporating subcooled boiling models is an effective approach for such analyses. However, most of the existing models are developed in some special flow and boiling conditions differing from that in IC engines, which inevitably leads to great discrepancies when they are directly applied to CFD analyses inside IC engine cooling galleries. A modified model with adjustable parameters is proposed based on the division description method in this paper. The predicted heat fluxes by different boiling models are compared against experimental data obtained in a cooling gallery simulator passage. The results indicate that a higher precision can be obtained by the modified model in predicting the boiling heat flux over a wide range of operating conditions as long as the parameters are accurately corrected. The performance of the modified model for practical IC engine applications is further assessed and the results show that the computational error is effectively reduced due to the incorporation of the modified model in the conjugate heat transfer simulation of the cylinder head and cylinder head cooling gallery.