Numerical Simulation Of Natural Gas Leakage In Deep-sea Pipeline Based On Pressure Gradient Change And Hydrate For Mation, Dissolution And Decomposition Mechanisms

In view of the special conditions of deep-water environment,considering t he pressure gradient change,the dissolution of natural gas and the formation,d issolution and decomposition mechanism of hydrate,a modified mathematical m odel based on the unit control volume method is established,and the numerical calculation of the mathematical model is realized by using MATLAB program ming language.A series of experiments carried out by foreign scholars are sele cted and numerical calculations are carried out for specific experimental conditi ons.The results are in good agreement with the natural gas leakage trajectories of the series experiments,which verifies the accuracy of the model.Aiming at the key factors affecting deep-water gas leakage and diffusion,i ncluding ocean current velocity and natural gas leakage flow,110 sets of nume rical simulation analysis were carried out,and the variation rules of gas traject ory,sea surface diffusion area and leakage time were discussed.Based on the analysis of a large number of numerical results,the criteria for dividing jet sta ge and convection stage in the process of deep-water gas leakage and diffusion are discussed,and the characteristics of gas movement in different stages are clarified.At the same time,aiming at the key analysis indicators in the proces s of leakage diffusion,including jet time,total leakage time,jet height and dri ft distance,the relationship between them and leakage flow and current velocit y is summarized,and several empirical formulas are fitted,which can provide rapid and convenient theoretical support for emergency rescue of engineering.Based on the modified mathematic model and the mature GUI function of MATLAB,a Deep-water Natural Gas Leakage and Diffusion Prediction Syste m is designed and developed,which can simulate the movement track of natur al gas leakage and diffusion for a specific project case,provide accurate data f or emergency plan formulation after the accident,and minimize economic and ecological losses.