Experimental study on premixed turbulent flame of methane/air in a spherical closed chamber

A turbulent combustion test platform is designed. It is demonstrated that the turbulent environment in a constant volume combustion chamber is isotropic and controllable. Based on the platform, the turbulent combustion characteristics of methane/air are studied. The collected flame image and combustion pressure data are analysed. The results show that when the initial temperature is 300 K, the initial pressure is 1 bar, and the equivalence ratio is phi = 1, the flame shape maintains self-similarity in the propagation process under different turbulence intensities. With the increase in turbulence intensity, there are more cracks on the flame surface and more wrinkles on the flame front; with the increase in turbulence intensity, the combustion propagation rate increases, the flame propagation rate increases at the same flame radius, and the maximum combustion pressure and the rate of pressure rise increase. When the turbulence intensity is constant, the test results of equivalence ratios of 0.8, 1.0 and 1.2 are compared. At an equivalent ratio of 1, the flame propagation rate and the stretch rate of the flame are maximized, and the maximum burning pressure and pressure rise rate are maximized.