Analytical and experimental investigations on heat transport capability of axially grooved aluminium-methane heat pipe

摘要

An analytical model for predicting heat transport capability of an axially grooved aluminium-methane heat pipe is presented, considering the effect of liquid-vapour interfacial shear stress and the axial variation of the liquid-vapour interfacial radius. The effects of undercharge and overcharge of the working fluid on the performance of the heat pipe are studied for the operating temperatures below and above a nominal operating temperature, respectively. In order to validate the model results, an axially grooved aluminium-methane heat pipe was fabricated and tested for its heat transport capability between 100 K and 160 K at horizontal tilt and an adverse tilt of 2.5 mm. It was observed that during heat pipe dry out, in addition to the evaporator temperature rise, there is a rapid fall in the condenser temperature due to cessation of fluid flow. Model results are found to be in reasonably good agreement with the experimental results till the nominal temperature of 130 K for both horizontal and adverse tilts. Beyond 130 K, the experimental heat transport capabilities at horizontal tilt are much more than the prediction which could possibly be due to the conductive and convective heat transfer through the puddle and the evaporative heat transfer through the thin film of the corners of the puddle extending into the evaporator. Beyond 130 K, the experimental heat transport capabilities at adverse tilt are also much more than the prediction which could possibly be due to the heat leak into the puddle entering into the adiabatic zone.