A Compact Reverse Rankine Cycle Combines Surface Enhancement and Jet Impingement to Remove High Heat Fluxes

摘要

We present an experimental assessment of a compact reverse Rankine cooling system driven by a small-scale oilfreelinear compressor. The expansion device (an array of micro orifices) is integrated with the evaporator to producetwo-phase jets that impinge on the surface of the element supplying the thermal load. The benefit of the proposedtechnology for high heat flux applications is twofold: the large heat transfer coefficient associated with spray/jetimpingement and the ability to maintain evaporating temperatures equal to or below that of the ambient. Here, thethermal performance of the system is improved even further by using resilient micro structures (micro pillarsfabricated by laser ablation) to increase the surface energy and promote higher values of heat transfer coefficientand critical heat flux. In addition to specific quantitative results on the capillary driving force of the enhancedsurfaces, we present thermodynamic performance data for the vapor compressor unit. High-speed video sequencesillustrate the phase change heat transfer phenomena involved.