Abstract: For the problems of flammable gas cloud formed by leakage in submarine gas pipelines and combustible gas transportation ships,based on the k-epsilon turbulence model and the eddy-dissipation model,numerical simulations of the formation and deflagration process of offshore flammable gas cloud were carried out under six wind velocity gradients (1-11 m/s),the specific influences of the wind velocity gradient on the deflagration pressure and temperature characteristics of gas cloud were studied.The results show that as the wind velocity gradient increases,the area of stable gas cloud decreases,the maximum pressure of deflagration decreases,the maximum temperature in the downwind low-altitude area decreases slightly,and the flame gradually moves away from the high-altitude area until completely stays in the low-altitude area,that in the low-altitude area,when the wind velocity gradient is 1 m/s,a large-area gas cloud and continuous high temperature cannot be formed,but when it is 3-11 m/s,a long-time and large-scale high temperature area will be formed easily.

Key words: offshore flammable gas cloud, deflagration pressure, deflagration temperature, eddy-dissipation model, numerical simulation, wind velocity gradient