"NUMERICALSIMULATION OF HEAT TRANSFER AND FLUID FLOW FOR CHAMFERSOLAR AIR HEATER DUCTED RIB ROUGHENED

Abstract

Computational analysis of heat transfer and fluid flow characteristics of -artificial roughness in the form of chamfered ribs (relative roughness pitch, p/e=4.57) on a broad, heated wall of a rectangular duct has been carried out in the present work for turbulent flow (Reynolds number range 3000-20000, which is relevant in solar air heater). The computational results have been compared with the experimental results reported- in the literature. Two turbulence models k — w and k — e were selected for comparing the predictions of different turbulence models with experimental results available in the literature. The 3D computational analysis is done for coarse, fine and very fine mesh in FLUENT. The total number of cells analyzed for very fine mesh is 20, 87,228. In this work, 8 no. of solution is found out for 8 no of experimental results and for each turbulence model. The results are examined using standard k — w and standard k = E model and compared on the basis of heat transfer enhancement and friction characteristics The results predict a significant enhancement of heat transfer in comparison to that for a smooth surface. There is a good matching between the predictions by standard k — w model and experimental results, where as there is much deviation in the results found k — a model.