Computer simulation of vortex flows near the condensation surface in the Laval-liked nozzle form vapour channel of short low temperature heat pipes at high heat loads

Abstract

The results of the computer simulation of vortex formation near the condensation surface in the Laval-liked vapour channel of short low temperature heat pipes (HP’s) at high heat loads are presented. For the first time it was found that the vapour vortex of moist compressible vapour flow near the condensation surface inside the vapour channel of short HP’s changes its rotational motion direction, depending on the thermal load magnitude on the HP’s evaporator. With low thermal loads, the rotational motion direction of the vapour vortex due to the Coanda effect and sticking moving vapour jets to the walls of the channel occurs from the periphery to the center of the vapour channel. While the thermal load increasing, the direction of rotation of the vapour vortex changes to the opposite, from the center to the periphery. The thickness of the liquid condensate film located under the vortex also depends on the magnitude of the thermal load and the direction of the vortex rotation. The numerical calculation of the condensate film thickness of working fluid were compared with experimental values depending on the thermal load on the HP’s evaporator and obtained by capacitive sensors.