A velocity-measurement equipment was developed to study the influence of fluid subcooling degree on the nozzle operation performance. The mass flow rate and the impact force were measured and the average mixing velocity of the two-phase fluid was obtained based on the momentum theorem. The influence of fluid subcooling degree on the average mixing velocity of the two-phase fluid at the outlet of LAVAL nozzles and the efficiencies of the nozzles was investigated on a refrigeration system with R410A. The experimental results show that the mass flow rate increased with the increase of the refrigerant subcooling degree at the inlet of the nozzles. However
the increase of upstream subcooling degree resulted in the significant decrease of the refrigerant mixing velocity and the nozzle efficiency. Under test conditions
the refrigerant mixing velocity at the outlet of the nozzle and the nozzle efficiency decreased by 35.7% and 33.9%
respectively
when the upstream subcooling degree increased from 0 ℃ to 11 ℃ for No.2 nozzle.
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references
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中国船舶集团有限公司第七一一研究所先进船舶发动机技术全国重点实验室,201108,上海National Key Laboratory of Marine Engine Science and Technology, Shanghai Marine Diesel Engine Research Institute, Shanghai 201108, China