Low temperature heat pipe heat exchanger is the key device in natural gas liquefaction system.As its core device,liquid nitrogen pulsating heat pipe has the characteristics of small size and high heat exchange efficiency,which can effectively overcome the problems of system freezing and compact equipment.However,it is difficult to carry out corresponding experiments,so it is of great significance to study the internal heat and mass transfer through numerical simulation.Firstly,the heat and mass transfer characteristics of a typical liquid nitrogen pulsating heat pipe are studied by using an adaptive phase transition model compiled by UDF.Then,the corrugated structure is optimized in the condenser,and the heat and mass transfer characteristics of the three types of liquid nitrogen pulsating heat pipes are compared with the phase distribution and the axis temperature variance when the liquid filling ratio is 50%.The results show that the variances on both sides of the 5 mm corrugated heat pipes are 51.49 K2 and 99.22 K2,and the working fluid circulation rate is fast and the axis temperature distribution is uniform.Finally,the heat transfer performance of the pulsating heat pipe with 5 mm corrugated structure is studied with liquid filling ratio of 30%,50%and 70%,respectively.According to the analysis of phase,temperature and axial temperature distribution,too high or too low liquid filling ratio will lead to liquid plug inside the heat pipe.When the liquid filling ratio is high,the axial temperature distribution is uniform,and the comprehensive performance of the heat pipe is the best when the liquid filling ratio is 70%.
liquid nitrogenpulsating heat pipenumerical simulationheat and mass transfer
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