Year : 2012, Volume : 37, Issue : 1to4
First page : ( 67) Last page : ( 72)
Print ISSN : 0379-0479. Online ISSN : 2349-2120. Published online : 2012  3.

Effective thermal conductivity of an axial groove cryogenic heat pipe

Kumar M. Senthil¹, Kumar A. Senthil¹

¹School of Mechanical and Building SciencesVIT UniversityVellore-632 014, Tamil Nadu

Abstract

A heat pipe is a device which transports heat at a high rate over considerable distance with a small temperature gradient. When the operating temperature of a heat pipe is less than 123 K, it is known as cryogenic heat pipes, and the working fluid used in the cryogenic heat pipes is any one of the cryogens like nitrogen, oxygen, hydrogen and helium depending on the operating temperature. This paper deals with development and studies of wire mesh wick and trapezoidal axial groove wick heat pipes with nitrogen and oxygen as working fluids. A special liquid nitrogen cryostat has been designed and developed for evaluating the performance of heat pipes. This consists of two main subsystems-a liquid nitrogen cryostat and instrumentation and accessory systems. Many investigators have carried out experiments on the cryogenic heat pipes, in which either the condenser is immersed in the liquid nitrogen or the condenser is connected to cryocooler whose operating temperature can be maintained at constant level by varying the cooling capacity. However, in most of the practical applications, where liquid nitrogen bath is used as the cold reservoir, it is very inconvenient to immerse condenser portion of the heat pipe into liquid nitrogen bath. The present study focus on the performance of trapezoidal axial groove wick heat pipe with the condenser connected to the reservoir externally. The performance of the heat pipe was determined at different temperatures between the triple point and critical temperatures of the working fluid. It is observed that the effective thermal conductivity of the heat pipe is about 2.9 times higher than that of equivalent diameter solid copper rod at about 100 K.

Top

Keywords

Axial groove cryogenic heat pipe, Effective thermal conductivity.

Top