Experimental and theoretical investigation on the effect of geometric parameters in electronic component cooling using jet impingement

Abstract

The present work deals with experimental and theoretical investigation on the effect of geometric parameters on the cooling of electronic components and sub assemblies in an air jet impingement cooling. To begin with an extensive literature survey has been conducted from the published literature and critically reviewed. In the process of literature review more than 100 relevant research papers are collected and a critical review is carried out to understand the state of the art in chosen field of investigation. Gaps in the published scientific literature are identified and the lacuna is high lighted. The present experimental investigation is an attempt to bridge some of the identified lacuna in the literature. As a part of the present experimental investigation a test rig has been designed, developed, fabricated, tested and commissioned keeping in view of the functional and operational requirements. Heat transfer coefficient have been determined in the temperature range of 30 to 1000 C of component temperature and in the range of Reynolds numbers from 5850 to 85000 of the jet. The geometric parameters like diameter of the jet and the distance between the nozzle exit and the target have been varied between 2 to 10. Three different geometric shapes of the nozzle, viz., circular, square and rectangular, have been investigated in the present work. The measured values of heat transfer coefficient are non-XII dimensionlised. Variations of non dimensional heat transfer coefficient have been represented as a function of geometric and flow parameters. New correlations are proposed based on the present experimental investigation. Results of the present work are compared with the published literature and discussed. Effect of nozzle aspect ratio on heat transfer rates decrease as the nozzle to electronic component spacing increases. The effect of nozzle aspect ratio on heat transfer is practically independent of the jet Reynolds number. The experimental results of the present investigation provide a good under standing of the fluid flow and heat transfer characteristics of air impinging jets. Uncertainty analysis has been conducted and typical range of uncertainty is also presented. Finally the scope for extension of present work is also identified.