Studies on capillary tube expansion device used in J-T refrigerators operating with nitrogen-hydrocarbon mixtures

摘要

Highlights?Speed of sound of N2-hydrocarbon mixtures estimated in two and three-phase regions.?In J-T refrigerators the capillary tube can get choked at high heat loads.?The choice of capillary tube controls the cooling capacity of J-T refrigerators.AbstractCapillary tube expansion devices are used extensively in small closed cycle J-T refrigerators operating with refrigerant mixtures due to its low cost and the absence of any moving parts. It is possible for J-T refrigerators operating with mixtures that the velocity of refrigerant mixture at capillary tube outlet reaches a value where it equals the speed of sound at certain conditions. The variation of the speed of sound of nitrogen-hydrocarbon mixtures used in J-T refrigerators has been studied in two phase (vapour-liquid) and three-phase (Vapour-liquid-liquid) region as a function of temperature and pressure in this work. Also the conditions under which choking occurs in practical J-T refrigerators is investigated.]]>