Research On The Influence Of Dilution Gas On The Front Structure Evolution And Propagation Characteristics Of Turbulent Premixed Flame Of Syngas

As a kind of gas fuel which attracts more and more attention,the application of syngas has a broad prospect.However,due to the variety of synthesis gas preparation methods,in addition to the main combustible gases hydrogen and carbon monoxide,there are also dilution gases with different components: nitrogen and carbon dioxide.Due to the complex composition of syngas,the physical and chemical properties of its fuel vary with the composition.Therefore,there are various combustion characteristics.It is necessary to carry out systematic experimental research to provide important data guarantee for syngas combustion,as well as more extensive basic data for turbulent premixed flame.A turbulent constant volume combustion test system is built.The system is mainly composed of constant volume combustion bomb,intake and exhaust system,turbulence generation system,ignition system and image acquisition system.Compare with the experimental results of other researchers,the system has good accuracy.Under the condition of dilution gas mixing,the structure characteristics of premixed flame with turbulent flow of syngas are studied.The characteristics of flame evolution under different initial parameters are studied.Matlab is used to extract the high-quality contour of the flame image,and the influence of diluent gas type and composition,turbulence intensity,equivalence ratio and hydrogen ratio on the local structure characteristics of turbulent premixed flame is analyzed.Furthermore,the local radius of the flame is extracted,and the correlation from beginning to end changes in the process of flame propagation is quantified,and the influence mechanism of flame profile development is clarified.The propagation characteristics of premixed flame of syngas are studied under the condition of dilution gas mixing.The characteristics of flame evolution under the conditions of diluent gas type and composition,turbulence intensity,equivalence ratio and hydrogen ratio are studied.The effective radius of flame is extracted,and the rule of time radius change and the mechanism of flame propagation speed are revealed.By calculating the density ratio of flame combustible gas and unburned gas,the promotion weight of different initial parameters on flame turbulent combustion speed and relative turbulent combustion speed is analyzed,and the influence of different initial conditions on flame propagation characteristics is revealed.Under the condition of dilution gas mixing,the acceleration characteristics of turbulent premixed flame of syngas are studied.The influence factors of flame nonlinear propagation are analyzed,and the change rule of flame critical radius under different initial conditions is analyzed.Through the correlation analysis of flame acceleration and fractal characteristics under the condition of dilution gas mixing,the law of flame acceleration index and fractal excess changing with different initial conditions is revealed,and the influence of different dilution gas types and components on flame self turbulence is quantitatively analyzed.