Investigations on water heat pipe under various modes of condenser cooling

Abstract

The heat pipe is a device, which does not require any external power to transport heat over a large distance, with minimal temperature difference. The simplicity of design, and ease of manufacture and maintenance of heat pipes have made them applicable in various fields of industry, such as energy conversion systems, cooling of nuclear and isotope reactors, cooling of electronic equipment, and high performance space applications. In the present work, three heat pipes of the same dimensions of 1 m length and 0.031m outer diameter were constructed with some modifications in the condenser section, in order to provide three different modes of cooling, viz, air cooling, water cooling and cooling with extended surfaces in the condenser section. Experiments are conducted to determine the surface and vapor temperature distribution, at steady and transient conditions for all the above said three modes of cooling in the condenser section. A CFD analysis was also carried out, and the results under steady state conditions are compared with the results obtained from the experiments and reported. The performance of the heat pipe depends on the type of cooling, and also the temperature at which the cooling medium is available. In the cases of fin cooling and water cooling in the condenser side, it is possible to maintain the temperature of the vapor and the surface of the evaporator section close to the saturation temperature, corresponding to the vapor pressure maintained inside the heat pipe at the start of the experiment. The effective thermal conductivity has been increased approximately by 40 % to 45 %. Further, a material saving of 400 % is achieved due to the hollow configuration made for the flow of the heat transfer fluid. The CFD results are in reasonable agreement with the results obtained from the experimental investigation. The CFD analysis will be useful to extend the analysis for other geometrical and dynamic parametric conditions. newline