Investigation Of Flammable GAS Leakage In The Building

Supported by national basic research program of china(973),Experimental investigation and numerical simulation are accomplished in this paper. After analysis,the rule of gas leakage in the building is found,which provide guidance for fire prevention and extinguishment in the building.In this paper FLUENT6.0 is used to simulate the gas leakage process under various boundary conditons(gas category window size and position ,leakage velocity etc)firstly.Then, an experimental table of cold gas leakage process is established,and experiment of cold gas leakage is accomplished.It is found that the distance of gas jet depend on velocity of jet ,based on results of numerical simulation ,relation between jet distance and velocity are fitted. After more analysis on simulative results ,it's found that critical factors which influence gas leakage process are position of window, leakage velocity,density of leakage gas.etc).Flammable range of mixture go up with time,till it reach the level of window. Afterwards,it vary little with time,time it spent to reach this quasi-equilibrium state depend on velocity of leakage.Concentration of flammable gas decrease gradually from bottom to top,but is not linear relation,thereinto,there is a point whose rate of change from rapidness to slowness,therefore,the definition of concentration platform is introduced into this paper.The height of the point is defined height of platform, various factors influence the height of platform are analysized in this paper ,empirical formula of gas leakage in building is generalized through many results of numerical simulation.Fmally,experiment results indicate that experimental result and simulation result are in a good accordance,as a result,simulation results and empirical formula are credible.