Extreme vibration increase of the heat transfer coefficient of short heat pipes

Abstract

Abstract The results of the heat transfer coefficient studies of the short linear heat pipes (HP’s) with a formed by the capillary-porous insert vapour channel in the Laval nozzle-liked form under high thermal loads and external vibrations are presented. Under high heat power loads the vaporization process in the capillary-porous evaporator and vapour propagation in the vapour channel acquires a pulsating character with a frequency of 400-500 Hz and the amplitude up to 103 Pa. For the first time it was experimentally detected that under external longitudinal vibration, attached to the HP’s body with an limited amplitude of 0.15 mm and frequency equal to the frequency of arising internal vapour pulsations, the HP’s heat transfer coefficient shows the resonance nature and increases by up to 20%. The increase in the heat transfer coefficient is due to the boiling process intensification in the grid HP’s capillary-porous evaporator.