Numerical Simulation On Explosive Boiling Process Of Liquefied Gas Storage Tank

It has been reported that the phenomena of explosive boiling of liquified gas tank under rapid depressurization occurred during using and tansporting of industrial As a consequence, researching the mechanism of pressure response during explosive boiling and proposing some prevention and control measures have a vital practical significance.From the perspective of fluid dynamics, A two-demension axisymmetric mathematical model of coupled response between pressure in tank and boiling phase change rate under the conditions of rapid depressurization was developed. The numerical simulation was done using the FLUENT software. Adopting the Relizable k-ε tubulence model, the mixture model for steam-water two phase flow under the conditions of rapid depressurization to simulate the flow field. Reasonably, good quantiative agreement was obtained between the experimental data and simulation for pressure, and the maximum deviation between them is less than15%. The favorable results suggest that the simple two-demension axisymmetric can be used for reasonable engineering calculations of the overall flow pattern. It was conducted to analyze the mechansim of coupled response between pressure and superheated liquid boiling phase chagne rate by calculation. We also detialed the process of evolution of the two phase flow during the discharge by analyzing temperature, flow field, the rate of vaporization, gas volume fraction and so on.In addition, it was carried on the analysis to the factors such as filling rate, initial temperature, opening size, the liquid temperature stratification which influenced the intensity of explosive boiling during rapid depressurization. And drew the following conclusions:Firstly, with increasing filling rate, pressurization multiples and the rate of pressure rise generally show an upward trend, while the relative percentage of pressure increases shows a downward trend, and the rate of pressure decrease shows an upward trend after the first drop as a whole. Secondly, with increasing initial temperature, the relative percentage of pressure increases, the rate of pressure decrease as well as the rate of pressure rise show an upward trend, while pressurization multiples shows an upward trend after the first drop as a whole. Thirdly, with increasing opening size, pressurization multiples is on a downward trend, while the relative percentage of pressure increases, the rate of pressure decrease as well as the rate of pressure rise all are on a upward trend. Finally, with increasing the degree of liquid temperature stratification, pressurization multiples and the rate of pressure rise present a downward trend, while the rate of pressure decrease present an upward trend, and the relative percentage of pressure increases presents two kind of change tendencies:it is greater when the liquid temperature have no stratification than when the liquid temperature existed a stratification. In addition, while the liquid temperature existed a stratification, as the degree of liquid temperature stratification increases, the relative percentage of pressure increases does not change significantly, and remains a constant value. In another word, from the perspective of tank safety, along with the filling rate, initial temperature and opening size increase, the tank is becoming increasing dangerous, while maintaining a certain stratification of liquid temperature is advantageous to safe operation of the tank.