Thermal enhancement study of a transverse inverted-T shaped ribbed solar air heater

Abstract

In the present study, the heat transfers and flow fields analysis in solar air heater duct having of transverse inverted-T shaped ribs is performed. The significant outcomes are presented in terms of Nusselt number, friction factor, thermal enhancement factor, and visualization of different fluid properties for the solar air heater (SAH). The computational exercise is done by considering various non-dimensional parameters like Reynolds number (Re), relative roughness pitch (P/e), and relative roughness height (e/Dh) for the test to enhance the rate of heat transfer through the rectangular SAH duct. The relative roughness pitch and Reynolds number are varied from 7.14 to 17.86 and 3800 to 18,000 respectively, considering a fixed value of relative roughness height of 0.042. A two-dimensional computational domain is selected for the study where an absorber plate made up of aluminum is subjected to a constant and uniform heat flux of 1000 W/m2. Among the various turbulence models, the RNG k-ɛ model with enhanced wall treatment is accepted as the most appropriate model to simulate the governing eqs. A Thermal enhancement factor of 1.87 is obtained as a result of enhancement in heat transfer for the SAH with an inverted T-shaped rib roughened absorber plate. The correlations are obtained for the Nusselt number and friction factor as a function of Reynolds number and relative roughness pitch by carrying out a non-linear regression analysis.