Analysis of Micro-Heat Exchanger for High Heat Flux

Abstract

Advancement in electronics technology makes humans life better but also creates new challenges for controlling their performance. Nowadays, devices are getting smaller to provide human portability without compromising on performance. Thermal management of electronics is a major challenge as it strongly affects the performance of electronic devices. Present thermal management system is lagging to provide cooling in new high computation electronic chips. This research is composed of predicting hydrodynamics and thermal behavior of single-phase flow in bend micro-heat exchangers by computational fluid dynamics (CFD) model equations. Geometry of models is made in SOLIDWORKS and numerical computation is performed in ANSYS Fluent 18.1 after generating mesh in ANSYS workbench. Channels of different bend angles from 100 to 90o are studied to find optimum bend while considering pressure drop, Nusselt number and space occupied by channel. After bend selection, combination of height and width of channel cross-section between 35μm to 300μm range is simulated with 320K, 325K, 365K and 370K base heater temperature boundary conditions. Best configuration of channel depending upon performance parameters including Nusselt number (Nu), pressure drop, base temperature and friction factor is selected for multi-channel configuration. Design point technique is used to reduce data and reach up to optimum design for multi-channel configuration. The present CFD study calculated pressure drop and Nusselt number for bend single and multiple channels, compared results with analytical values showing close agreement. Furthermore, secondary vortices effect on pressure drop and heat transfer is studied. It is found that square channel provides best overall performance and dean vortices are generated after Reynolds number value of 600 which participates in enhancing convective heat transfer capability of micro-channel.