Experimental study of the turbulent flow around a single wall-mounted prism obstacle placed in a cross-flow and an impinging jet

Abstract

This paper describes the experimental part of an electronics cooling research project. To undertake the experiments a test rig has been designed and assembled which represents a channel made by two parallel printed circuit boards (PCBs). Different arrangements of heated prismatic bodies can be mounted on the walls of the channel simulating electronic components. These bodies are cooled combining a channel cross-flow and impinging jets issuing from the walls. The working fluid is air and the maximum Reynolds number (calculated respect to the channel height) is 13740. The test rig has been designed to take flow measurements using different experimental techniques such as hot wire anemometry (HWA), particle image velocimetry (PIV) and infrared imaging (IR). Experimental data on fluid flow features around electronic components will be used to develop and validate turbulence models that will be implemented in Computational Fluid Dynamics simulations. The presented results are two preliminary experimental studies to analyse the influence of the component height (h) and the Reynolds number on the flow structure around the component. The first study was made with the component in a cross flow without impinging jet and in the second study an impinging jet was added to the cross flow. The Reynolds numbers employed are close to those used in applications within the electronics industry. The measurement mean (U, V), rms velocity (urms, v rms) profiles in three main regions of the flow, namely, the wake, the upper and the side region have been obtained using the hot wire anemometry. From theses measurements the lateral flow separation, reattachment points and recirculation have been studied. © 2010 WIT Press.