HEAT TRANSFER IN SHEAR-DRIVEN THIN LIQUID FILM FLOWS

Abstract

The objective of the study is to investigate hydrodynamics and heat transfer in a shear-driven liquid film flow. This process is relevant to fuel flow inside lean pre-mixed pre-vaporization (LPP) chambers. A combined numerical and experimental study has been performed to determine the heat transfer in gas-driven thin liquid films on the outer surface of vertical heated tubes. Numerical simulations have been performed using the volume of fluid (VOF) method implemented in an open source computational fluid dynamics (CFD) code OpenFOAM for turbulent air/water flow conditions. The code has been extended for simulation of two-phase flows with heat transfer. The Reynolds averaged Navier-Stokes equations (RANS) with the k - \textgreeke turbulence model for gas-liquid two-phase flows have been solved using the finite volume method. The results on wall temperature distribution and average film thickness have been compared with experimental data. A reasonable agreement between the simulations and experiment has been found. The results indicate that the heat transfer is enhanced with increasing gas Reynolds number due to the film thinning and intensification of convection.