Study On The Influence Of Sloshing On The Evaporation Rate Of LNG Tank

Today's energy problem is still a sharp contradiction.The depletion of oil resources is accompanied by the rise of new energy sources.The advantages of clean combustion,rich reserves and high cost performance of natural gas make natural gas play an important role in the upgrading of the world's energy structure,especially in the marine transportation industry.A large number of conventional power ships are converted into pure natural gas powered ships or Hybrid ship,LNG carrier and LNG bunkering ship came into being.As a new type of ship,the design of cryogenic tank and the law of LNG evaporation have always been the focus and difficulty of the research.Mastering the law of LNG evaporation is the core technology of mastering the design and construction of cryogenic tank in LNG ship and the key to reducing the operating cost of LNG ship.In this paper,theoretical research and numerical simulation are used to study the law of LNG evaporation in the thin film cryogenic tank of LNG ship.The steps of tank model and calculation of evaporation rate are simplified.The evaporation rate of LNG in the cryogenic tank under the two states of static and sloshing are simulated and calculated respectively.The law of LNG evaporation performance in the cryogenic tank is summarized through comparative experiments,and the low filling rate under different filling rates is preliminarily predicted The evaporation rate of LNG in the tank and the conclusion that sloshing has an effect on the evaporation rate of LNG in the tank are drawn.The main contents of this paper are as follows:(1)The evaporation performance of LNG in two states of static and sloshing is studied theoretically.Through theoretical analysis and demonstration,the design parameters needed for numerical calculation,theoretical basis for simplified model and numerical calculation methods for two states under different filling rates are obtained,and the experimental research methods are analyzed and summarized;(2)Based on the theoretical study,the membrane tank is simplified into a simple rectangular tank,and a method for calculating the evaporation rate of cryogenic liquid in the sloshing state of the rectangular tank is proposed;(3)Through a large number of numerical simulation of LNG cryogenic tank in two states of static and sloshing,it is concluded that sloshing has an impact on the evaporation rate of LNG in cryogenic tank when the filling rate is different in the two states.Through the data comparison,it is found that the evaporation rate of LNG in static state is lower than that insloshing state when other conditions are the same and the filling rate is the same The results show that sloshing has an effect on the evaporation rate of LNG.The lower the filling rate is,the lower the filling rate is,the greater the influence of sloshing on the evaporation rate is;(4)By comparing the data and images,the results of numerical simulation are analyzed.It is found that the phenomenon of heat and mass transfer of gas-liquid in sloshing state with the same filling rate will be more serious than that in static state.The temperature of gas layer in sloshing state is lower than that in static state,while the temperature of liquid layer in sloshing state is higher than that in static state.