Research On The Influence Of Plasma On Combustion Modes Under Supersonic Speed

For the ramjet engine,its biggest requirement is to be able to operate in a wide Mach number range,but the conversion of different working states under different flight conditions has an important impact on engine performance.The plasma generated by the discharge has different combustion mechanisms due to its physicochemical characteristics,which provides a new direction for the conversion of combustion modes by changing the way of combustion heat release.Therefore,this article studies the method of using plasma to achieve combustion mode conversion,using a combination of experiment and numerical simulation to analyze the principle of plasma to combustion mode conversion,and verify the principle of plasma to combustion heat release change.Four aspects of simulation calculation and experimental verification of plasma to combustion mode conversion are carried out with progressive research ideas.First,summarize the basic characteristics of the combustion mode and the mechanism of its conversion through different paths,analyze in detail the conversion principle of the plasma by changing the combustion heat release distribution,and then obtain different plasmas through numerical simulation.As a result of the excitation intensity having different degrees of enhancement effect on the combustion heat release rate,it was found that plasma can change the combustion heat release distribution.Secondly,according to the discharge and combustion characteristics in the supersonic combustion chamber,a coaxial low-speed co-flow combustion device was designed,and the theory verification experiment of plasma’s change of combustion heat release was carried out.The flame light intensity,maximum width and other combustion characteristic parameters were analyzed under different discharge intensity,discharge position,and co-current equivalent ratio.The law of the effect of plasma on the distribution of combustion heat release was obtained,which proved that the plasma can Affect the combustion heat release.Then,the numerical simulation method is used to analyze the flow field characteristic parameters of the combustion state under the conditions of different fuel equivalent ratios and different discharge excitation strengths to determine the combustion mode under different conditions,so as to obtain different discharge excitation intensities,The relationship between the oil equivalent ratio of the center and the supporting plate and the combustion mode,and grasp the effect of the combustion heat release under the plasma effect on the combustion mode under different working conditions.Finally,the experimental work of plasma to combustion mode conversion is carried out in an axisymmetric engine environment under supersonic flow conditions.First carry out the design of the discharge excitation plasma device and its integrated installation,and then carry out the combustion mode conversion experiment under different discharge excitation intensity under different fuel equivalent ratios of the center and the support plate,and compare the experimental results with the numerical simulation results,and realize The conversion of the combustion mode under different plasma excitation intensities verifies the feasibility of the plasma to change the combustion heat release to achieve the combustion mode conversion.