The Study On Fire Smoke Movement Law And Damage Control In Mine Sloping Roadway

Fire is one of major disasters in coal mine,the existence of sloping roadways makes fire development more complex.There is a high difference between entrances and exits of sloping roadways in the mine.When fire occurs,the temperature in this environment rises,and at the same time,the gas density decreases,both result in the buoyancy effect.The high temperature flue gas is always along the roadway bottom-up flow.The buoyancy effect of fire smoke can change the state of air.The influence of roadway inclination on the spread of flue gas can not be ignored.This paper aims to study the fire smoke movement in sloping roadways and flue gas temperature distribution,Furthermore,a measure to control smoke is put forward by taking advantage of ventilation,making recommendations to help staff of mine escape safely and reduce material loss.In this paper,on the basis of the diffusion of smoke in the fire tunnel,the three regional model of the resistance to the smoke flow is presented according to the smoke propagation.Then the energy equation is solved for each zone.And a routine that calculates the temperature distribution along the length of the tunnel is included as well as the computation of the resistance of smoke flow due to buoyancy effect.In addition,the application of the resistance of smoke flow due to buoyancy effect of some sloping tunnels illustrates its composition and influencing factors such as fire intensities,tunnel slope and fire lengths by the software of MATLAB.The results show,the resistance of the buoyancy effect is the result of the comprehensive function of the fire intensity and the angle of the roadway,providing the basis for determining the influence factors of the critical wind velocity.Then,in order to study the effect of the roadway gradient on the smoke temperature distribution and smoke spreading length under different ventilation modes,a physical model of sloping roadway is constructed with the help of numerical simulation software of FDS,and some of slopes of 0o~30o were taken into account.The study shows that,when ventilating along the sloping roadway,the maximum temperature is generally lower than the level of roadway with wind speed.On the contrary,inverse the sloping roadway,the maximum temperature is generally higher.As a result,the critical wind velocity required for the different ventilation modes of the sloping roadways should bediscussed separately.Finally,the research on critical wind velocity is simulated by using FDS as well,discussing the variation of critical wind velocity in detail under different sloping roadways or different ventilation modes.The results show,positive or negative ventilation in sloping roadways makes difference to critical wind velocity.When ventilating along the sloping roadway,the existence of the angle makes the critical wind speed smaller;conversely inverse the sloping roadway,the existence of the angle makes the critical wind speed larger.Then based on the simulated data,modified formula of critical wind speed about sloping angle is obtained by the method of data fitting:1)ventilating along the sloping roadway,kg=0.98818-0.00765?;2)ventilating inverse the sloping roadway,k_g=1.01521+0.00776?,providing theoretical basis for the determination of critical wind velocity.