Study On Dispersion Concentration Field Of Indoor Gas Leakage Under Multi-factors Coupling Action

With the development of the exploitation and consumption of natural gas, naturalgas has become indispensable in people’s daily life. However, due to the ageing,corrosion and man-made damage of the pipelines, the pipeline leakage accidents occurfrequently. The flammable and explosive property of natural gas can easily contribute toserious accidents such as fires and explosions once the gas leak in the limited space.Mwanwhile, the spread of gas to the outer atmosphere will be influenced bymulti-physics (temperature, humidity and concentration field). Therefore, a systematicresearch on the influence of leakage dispersion under the meteorological factors duringthe gas leakage dispersion process has certain guidance significances and referencevalue for the rescue and evacuation after the accident. The dispersion numericalsimulation development of flammable and poisonous gas is one of the methods ofpredicting and evaluating the risk through the gas leakage diffusion. In view of theprevious research which is limited to the influence of a single factor on indoor airpollutants diffusion, this paper will discuss the diffusing regulations of indoor gasleakage under multiple factors coupling action.Based on the principle of thermodynamics of irreversible processes andthermodynamics of statistics non-equilibrium, a model of temperature and humiditygradient coupling diffusion model was established, which can explore the coupledeffects of indoor temperature and humidity concentration gradients on the diffusion ofair pollutants. Combined with the theory of gas leakage diffusion and turbulentdiffudion, the mathematic model of gas leakage and diffusion is established under thecoupled of factors.By Matlab development tool, the program of gas diffusion model is written basedon coupling multiple factors, then simulated the gas leakage dispersion by inputtingdifferent environment of temperature and humidity distribution, quickly acquiring thegas concentration in the forecasting point, and getting the laws of dispersionconcentration field which influence by temperature and humidity distribution.Finally, based on the three conservation functions and the turbulence models，adopting the simulation of the indoor gas diffusion using Fluent software of CFD. Byinputting different distribution of temperature and humidity, get results and compare with the results of the oretical analysis. The research rasults coincides with the leskageand diffusion theory, thereby the correctness of theoretical analysis in this paper isproved.The research method provides a new clue for the natural gas leakage and diffusiontheoretical research. The discipline gained from analysis has certain guidancesignificances and reference value for the rescue and evacuation after the accident.