A study on the effect of non-uniform spacing on the performance of forced convection cooling of discrete heaters: A numerical investigation

Abstract

A numerical simulation of forced convection conjugate heat transfer has been performed for flow over discrete, volumetrically heated rectangular obstacles mounted on the lower wall of a horizontal channel. Non-uniform spacing between the heaters is investigated with the help of isotherms, streamlines, heatlines and entropy generation along with cup-mixing temperature by fixing the geometric parameters for flow Reynolds number between 100 and 1500 (100≤ReL≤1500) and a fixed thermal conductivity ratio of 10 (ks/kf). To quantify heat transfer, local and average Nusselt number have been used. Pressure drop is calculated with the help of the apparent friction factor. Together, these two parameters provide the quality factor, which measures the performance of the discrete heaters. It has been found that the effect of spacing variation is not limited to the proximal heaters. Irregular behaviour in heat transfer has also been noticed in the results. As we move downstream of the flow, the heat transfer will decrease; however, there are a few particular cases where it was noticed that the performance of the last discrete heater is better compared to the heater just upstream of it.