The invention discloses a low-temperature
liquid storage tank pressure prediction method based on a non-
thermal equilibrium state model, and aims to improve the calculation speed of a pressure evolution law so as to reduce the time required for predicting the pressure of a
storage tank. The method comprises the steps that firstly, a
pressure sensor, a temperature sensor and a liquid level meter are used for collecting the temperature of a current
gas phase and
liquid phase area of the low-temperature
liquid storage tank, the pressure in the
storage tank, the vacuum degree of a heat
insulation layer and the real-time liquid level; secondly, transmitting
signal data obtained by monitoring of the sensor to a processor, and checking the density,
phase change latent heat and thermodynamic energy of gas and liquid phases in the
storage tank through REFPROP
software; then establishing a three-dimensional model and a heat and
mass transfer relationship of the storage tank, and performing
heat transfer analysis on gas-phase and liquid-phase media in the storage tank; secondly, performing
energy analysis on a
gas phase region, a
liquid phase region and a gas-
liquid interface in the storage tank according to the established three-dimensional model and a
heat transfer analysis result, and selecting a
proper time step to perform iterative calculation so as to ensure the calculation precision of each step; storing the calculation result of the previous step, and searching and taking thermodynamic parameters of the next
time step through REFPROP
software according to the parameters obtained through calculation; finally, the
safe storage time of the storage tank under the current liquid filling volume and the heat insulation performance is calculated, and safe work of the storage tank is guaranteed.