평판형 PHP의 횡방향 전도 열전달이 유체의 진동 운동에 미치는 영향에 관한 연구

Abstract

Pulsating Heat Pipes (PHPs) can be made by engraving channels on the substrate plate, which are called Flat-Plate PHPs (FP-PHPs). In FP-PHPs, there exist mainly two heat transfer paths, heat transfer by the oscillating motion of working fluid and the axial conduction through the substrate plate. However, there also exists transverse conduction through the channel wall, which is expected to have a bad effect on the thermal performance of the working fluid due to a balancing effect. In the silicon-based PHP, the number of liquid slugs or vapor plugs is equal to the number of turns and the five vapor plugs dwell in the evaporator section most of the times. By examining the balance of forces exerted on a liquid slug, it is found that the motion of the liquid slug is governed by the force due to the pressure difference between neighboring vapor plugs. In the PHP w/ cutting, vapor plugs can expand and contract actively, while the volume rate of change of a vapor plug is restricted by the transverse conduction in the original FP-PHP. Due to the more active expansion and contraction of vapor plugs, there exists a larger amplitude oscillating motion of working fluid in PHP w/ cutting and this results in the higher effective thermal conductivity of the working fluid.