Experimental Study On Gas-liquid Separators Of Gravity Feeding Refrigeration System

Based on thermal siphon principle, gravity feeding recirculation refrigeration systemdepends on the height difference between gas-liquid separator and evaporator to realizesuper feeding liquid for evaporator, improving the heat exchange efficiency of evaporatorgreatly. Gas-liquid separator is one of the key components of gravity feeding refrigerationsystem. Under-sizing a separator can lead to separate gas and liquid refrigerant difficultlyand liquid entrainment of compressor intake or gas entrainment of evaporator liquid feeding,etc. expensive long-term operational fee; over-sizing a separator can lead be an expensiveinitial investment of equipments, which may not be able to absorb. So, it is necessary todesign the structure form of gas-liquid separator reasonable, especially for gravity feedingsystem. Liquid supply power of evaporator is provided by fluid column pressure head, sothe structure of gas-liquid separator directly affects the initial investment, the mass ofrefrigerant and the running performance of gravity feeding system. Therefore, it ismeaningful to design a suitable structure of gas-liquid separator to complete gravity feedingrefrigeration system.Droplet dynamics is adopted to analyze a single droplet in gas-liquid separator, and asingle droplet model is used to design gas-liquid separator. By using fluent software tosimulate internal flow field of gad-liquid separator, it is found that the flow field ofdesigned gas-liquid separator is similar with the original separator. The diameter ofgas-liquid separator is reduce to75%of the original separator, and average liquid volumefraction of outlet facet is1.0689108, which can meet the requirement of practicalrefrigeration system.Modifying the test apparatus of gravity feeding refrigeration system, heat balancemethod is used to test the running performance of gravity feeding refrigeration system withdifferent gas-liquid separator. This experiment set up six operating modes to analyze theinfluence of gas-liquid separator structure to gravity feeding refrigeration system under thesame condition.Experimental studies have shown that, the structure of gas-liquid separator has littleimpact on the performance of refrigeration system; because the separator diameter reduced25%, the fluctuation of evaporating temperature become more severe than the original one;the refrigerant storage capacity of separator is greatly reduced, and when the liquid level isin liquid level control, the refrigerant storage capacity is reduced to19.1%of the original one.