On heat transfer mechanism in coolant layer on bottom cover of a two-phase closed thermosyphon

Abstract

The authors hypothesize that the intensity of all thermophysical and hydrodynamic processes in a thermosyphon depends, first of all, on the intensity of heat transfer in the coolant layer on the bottom cover and on the free surface of this layer. Based on the experimentally obtained temperature fields in a two phase closed thermosyphon, the authors have formulated a mathematical model of heat transfer in such heat exchangers which differs from the known models by accounting for conduction and convection only in the coolant layer on the bottom cover and conduction in the evaporation section of the thermosyphon. The calculated temperatures in characteristic points of the coolant layer comply with the readings of thermocouples. The results of numerical simulation provide grounds for concluding that the thermogravitational convection in the coolant layer on the bottom cover plays a dominant role in controlling the intensity of heat transfer in the thermosyphon.