Numerical Simulation Of The Multicomponent Nature Gas Diffusion On The High Pressure Leaking Pipeline

FLUENT software was used as the numerical simulation tool to study the law of multicomponent natural gas diffused in air when the high pressure pipeline was broken in this article, assuming this multicomponent natural gas contains both methane and sulfureted hydrogen. The operation parameters which were recommended to the"West Gas Piping to East"project were computed as the basic conditions. Changing the influence factors such as wind velocity, leaking pressure, the results of gas diffusion were analyzed to decide the relationship between the concentration and influence factors. The main conclusions were expressed as follows.Multicomponent nature gas was jetted from the leak hole with the axisymmetric super expand jet law under the condition of the no wind and normal operation parameters. During the course of diffusion, maximum pressure and velocity core were around the leak hole. Data of the velocity fit the experiment. Temperature decrease when it got through the hole. The maximum concentration of sulfureted hydrogen was around the wall and the area above the hole. According to the result of simulation, almost the whole simulation area was dangerous to people. Results were totally different between the gas only contains methane and the gas contains both methane and sulfureted hydrogen. It was more dangerous when the gas contains sulfureted hydrogen. The safe area increase when the percent of sulfureted hydrogen grows up.The radium of leaking hole, wind and leaking pressure could influence gas's diffusion. In the same point of simulating area, the concentration of nature gas grew when the radium increased. When there was wind, the isoline of every parameter and the center of dangerous area moved downwind. The wind's influent increased along the centre line upper air. Changing leaking pressure, the dangerous areas were different, but the changing swing was small. Simulating the situation after light the fire, we could find that the safe area greatly increase from the one which was not on fire.