Numerical simulation of flow boiling heat transfer and pressure drop in a corrugated plate heat exchanger at low mass flux and vapor quality conditions

Abstract

This article reports on a numerical study conducted to predict the flow boiling dynamics, heat and mass transfer, and pressure drop in corrugated plate heat exchangers. The conservation equations are discretized in the context of the finite volume method and solved using the mixture multiphase flow model. The Semi Mechanistic Wall boiling model, based on Chen’s method, is used to calculate the wall heat flux. Moreover, Lee’s model is adopted to compute the evaporation/condensation rate. Water is used as the working fluid and solutions are generated at low mass flux and vapor content for subcooled and saturated liquid water at the inlet. An experimental setup is developed, and measurements are performed to validate the numerical solution. The model shows good agreement with experimental data and with values obtained from available correlations for the two-phase heat transfer coefficient and pressure drop. Results indicate an increase in the heat transfer coefficient when the mass flux is increased, and wall and inlet flow temperatures are decreased. Further, the drop in pressure increases with an increase in the mass flux, wall temperature, and vapor quality. The flow boiling heat transfer is found to be in the nucleate boiling regime. Additional new insights on the complex flow boiling process are reported by utilizing contour plots of the mass evaporation rate, vapor fractions, and velocity vector fields.