Global and local performances of a tubular micro-pulsating heat pipe: experimental investigation

Abstract Heat exchanger optimization is mandatory in almost any industrial application. Thanks to their performances, the Pulsating Pipes (PHPs) are a very interesting Micro-PHPs, which defined as PHPs with tube that has hydraulic diameter < 500 μm, have shown big advantages terms of ability dissipate high heat fluxes, reduced size, and low weight. However, great majority works investigate thermal behavior micro-PHPs only deal average performance system, usually represented global resistance device. Our study aims begin fill this lack by investigating local typical multi-turn micro-PHP. A micro-PHP characterized seven turns realized stainless-steel pipe was investigated. It positioned vertical position, evaporator at bottom, it partially loaded HFC-134a. The studied tubular, while totality investigated date constituted microchannels engraved silicon-based wafer, they present potential three-axis flexibility compared flat To highlight different functioning each turn, an infrared camera used acquire temperature distributions on wall PHP condenser. found best reached for filling ratio 46% input ranging between 1.9–3.7 W. thoroughly pulsating proposed PHP, dominant frequencies were performing wavelet analysis. results allow identification flow regimes, such start-up, non-persistent oscillating (0.05–0.6 Hz; Q net 2.3 W), quasi-periodic (0.6–1.5 = 2.8–4.7 W). Eventually, approach herein can provide worthy evidence about fluid motion inside thereby allowing overcome limits introduced adoption transparent materials direct visualization or invasive insertion pressure sensors, particularly devices small dimensions.