Experimental Investigation of Thermal Performance of Bi-porous Wicks for Loop Heat pipe Evaporator using IR Thermography

With the miniaturization of electronic components, thermal management of electronic devices and systems becomes a crucial problem. A loop heat pipe is a promising solution for many contemporary and future thermal management problems. Loop heat pipe is a passive, flexible and robust two-phase heat transfer device. A porous wick is the heart of loop heat pipe which strongly and singularly affects its thermal performance. The main aim of the present research is to develop a porous wick and investigate the heat transfer phase-change in the LHP evaporator by using IR thermography. A bi-porous copper wick is developed by using naphthalene as pore former. It is observed that porosity and permeability increase with increase in pore former content and decreases with increase in sintering temperature. The evaporative heat transfer coefficient at the internal fin-wick interface decreases with increase in the heat input because the liquid vapor interface moves away from the heated fin with increase in heat load. Infra-red thermography is an excellent tool to carry out diagnostics and design of LHP wicks.