Experimental study on heat transfer and fluid-flow enhancement of a spherical shape obstacle solar air passage

Abstract

This paper presents the outcome of experimental examined of Nusselt number and friction factors in a spherical obstacles solar air passage. Investigation has been performed to examine the thermal and hydraulic data from a solar air passage with spherical obstacles on the heated wall. The Reynolds number base on the hydraulic diameter of the solar air passage varied from 45.00 to 16.500, relative sphere diameter varied from 0.130 to 0.217, stream wise spacing of 4.04 and span wise spacing of 4.04. Experimental results pertinent to heat transfer and pressure drop was determined for various sets of roughness and flow parameters. The experimental results show that the heat transfer is increased around 4.7 times than plane surface solar air passage. The thermal and hydrodynamic performance parameter based on equal pumping power was found to be highest for spherical shape dia of 0.195. The superior value of overall thermal performance parameter is 2.83 corresponding to spherical shape dia of 0.195.