Temperature Evolution of Large-Scale Oscillating Heat Pipe with Methanol as the Working Fluid

Abstract

As a family of heat pipe, oscillating heat pipe (OHP) has many additional unique operating parameters. This paper examined the characteristic of temperature evolution from startup until dry-out stage of an OHP with extra-long dimension using methanol as the working fluid. The temperature evolutions were studied in the range of adjustable heater load from 20 Watts up to 467 Watts. The temperature evolution associated with flow pattern in two-phase regime as follows: chaotic intermittent slug flow, switch and reversed flow, transition to annular flow and stable circulation and dry-out stage. The lowest thermal resistance was 0.057 °C/W at 410 Watts. At the switch/reversed flow stage, the evaporator temperatures were separated into a certain level, which was a proof of net circulation flow