The Role of Cylinder Obstacles before Air Conditioning Filter in the Quenching of Flame Propagation during Their Gas Deflagration Production Process

Abstract

The reticulated polyurethane foam has an extensive application in the ventilation and air conditioning systems as filtration material due to its high filtration velocity, low flow resistance and high filter efficiency. Mostly, the reticulated polyurethane foam is produced from the closed-cell polyurethane foam by the deflagration process of the combustible gas. However, in the actual production process, the quenching of the flame in the porous media of the polyurethane foam always leads to the failure of production process, which reduces the production efficiency and results in economic losses. The thickness of the reticulated foam highly affects the propagation characteristics of the flame due to the effect of the interactions of flame and the reticulated foam. Thus, this paper aims to reveal the effect of the obstacles of the porous media of polyurethane foam on the flame propagation characteristics of gas deflagration. A cylindrical explosion test tank was designed, which has a diameter of 315 mm. The flame propagation characteristics and pressure wave in the presence of reticulated polyurethane foam were numerically investigated. A parameter study of the thickness of the reticulated polyurethane foam on the propagation and quenching of the flame is discussed. It can be concluded that the flame propagation speed decreases when the flame enters into the reticulated polyurethane, it increases as the thickness of the reticulated polyurethane increases, in addition, the final deflagration temperature and the temperature rise rate decrease with the increase of the thickness of the reticulated polyurethane, and the temperature rise rate decreases when the flame enters into the reticulated polyurethane. It is due to the destruction effect of the free radicals and absorption effect the heat of the flame by the reticulated polyurethane. Besides, the deflagration overpressure and the pressure rise rate decrease with the increase of the thickness of the reticulated polyurethane, which is due to the inhibitory effect of deflagration overpressure.