Experiments on flow and heat transfer characteristics of a rectangular channel with a built-in adiabatic square cylinder

Abstract

Experimental investigation of unsteady flow past a square cylinder confined in a channel and the associated heat transfer phenomena in laminar flow regime is carried out using purely non-intrusive diagnostic technique. A Mach-Zehnder interferometer has been employed to make the path-averaged measurements of the quantities of interest. Five different Reynolds numbers are considered and the heat transfer rates in the channel with and without the presence of square cylinder have been compared in the wake region of the built-in cylinder. Vortex shedding frequencies are determined using schlieren technique. Both the temperature field and the vortex shedding frequencies have been completely determined using non-intrusive techniques. The whole field experimental results depict significant augmentation in the wall heat transfer rates in the presence of a cylinder when compared with its counterpart (channel without cylinder). Flow instabilities induced by the square cylinder alter the thermal boundary layer profile and hence temperature gradients near the channel walls become steeper and consequently the wall heat transfer is significantly increased.