Numerical Study On Suppressing Flame Propagation And Pressure Wave With Porous Media

The research of combustion and explosion of combustible gas in pipeline is an important subject in the fields of safe technology, in order to perfect and develop the inhibition research of the combustion and explosion of combustible gas in pipeline, this paper takes use of numerical simulation method to study the combustion and explosion of combustible gas in pipeline with porous materials inner liner, as well as to seek after the new ways or new methods of explosion inhibition will benefit for both of explosion prevention and the security of production and people. The main works and conclusions are in the following:(1) The numerical model is setup to simulate the flame propagation situation in pipeline with aluminum silicate cotton and entity barrier, the effective inhibition effects of aluminum silicate cotton to porous materials on flame and pressure wave in pipeline is obtained. This paper takes use of numerical simulation method to study the inhibition effect of aluminum silicate cotton porous materials on acetylene/air and propane/air. The initial and boundary conditions as follow:stoichiometric rate and atmospheric pressure are used for initial concentration of acetylene (6.74%), propane (6.02%) and initial pressure; the inside diameter and length of pipe, which is closed at ignition end and open at the other, are 81 mm and 2200mm respectively.(2) The effect of the length and thickness variation of aluminum silicate cotton porous materials on flame propagation velocity is obtained. At the same thickness, there is a power function relationship between flame propagation velocity and the length of aluminum silicate cotton, that is, the flame propagation velocity decrease with increase of the length of aluminum silicate cotton. When the length of aluminum silicate cotton is less, with the thickness variation of aluminum silicate cotton, the flame propagation velocity firstly increase and then decrease, that is, there is a critical thickness.When the thickness is less than the critical value, the aluminum silicate cotton play a role in inhibiting flame propagation, but when the thickness is more than the critical value, the aluminum silicate cotton play a role in combusting, and accelerate the flame propagation(3) The effect of the length and thickness variation of aluminum silicate cotton porous materials on pressure wave is obtained. At the same length, there is a linear function relationship between overpressure value of pressure wave and the length of aluminum silicate cotton, that is, the longer the aluminum silicate cotton is, the smaller the overpressure value is. When the length of aluminum silicate cotton is less, the overpressure value firstly increase and then decrease, that is, there is a critical thickness, but when the length is longer, the overpressure value decrease continuously with the thickness increase.(4) There is a inverse relationship between the porosity and the inhibiting ability of aluminum silicate cotton on flame propagation velocity and overpressure value. The larger the porosity is, the weaker the inhibiting ability is, on the contrary, the smaller the porosity is, the stronger the inhibiting ability is.