NUMERICAL SIMULATION FOR THERMAL DESIGN OF A GAS WATER HEATER WITH TURBULENT COMBINED CONVECTION

摘要

This article investigates the effects of geometric parameters on a turbulent asymmetrical heat transfer in vertical channels with radiation and blowing from a wall. Hydrodynamic behaviour and heat transfer results are obtained by the solution of the complete Navier-Stokes and energy equations using a control volume finite element method. In this paper, commercial codes were used to solve the equations. The equations involved were numerically solved with three turbulent models including Spalart-Allmaras, R-N-G k-ε with 'standard wall function' wall nearby model, R-N-G k-ε with 'enhanced wall treatment' wall nearby model and 'ray tracing' radiation techniques. Turbulent flow with 'low Reynolds Spalart-Allmaras turbulence model' and radiation with 'discrete transfer radiation method' was modelled. The results were compared with experimental data and appropriate methods were selected for turbulent modelling. The problems of different Grashof number, Reynolds number, radiation parameters and Prandtl number were solved and the effects of geometric parameters on the fluid flow, radiation-convection-blowing heat transfer and the total efficiency were determined.