Research On Ignition And Combustion Characteristics Of Gaseous Fuel Combustion Chamber

In order to alleviate the energy shortage and reduce the emission of pollutants,gas turbines burning gaseous fuels have become one of the important research directions of gas turbine technology at home and abroad.As people pay more and more attention to the operational reliability of gas turbines,the research on the ignition and combustion characteristics of the gas turbine combustor has important practical value for the design and use of the combustor.This paper takes a certain type of Ring tube combustion chamber burning gaseous fuel as the research object,and uses numerical simulation method to systematically study the ignition and combustion characteristics of the combustion chamber burning natural gas and medium-heat value gas.Mainly carried out the following research work:(1)Research on the ignition characteristics of the plasma igniter was carried out,and the ignition characteristics and stable ignition boundary of the plasma igniter under different inlet conditions were obtained,and the reasons for the ignition failure were analyzed.In order to improve the characteristics of the hot jet at the exit of the igniter,the influence of the nozzle hole diameter,arrangement position,and extension distance on the combustion flow field and exit parameters of the plasma igniter was analyzed.The structure of the plasma igniter was optimized,and the applicability of the optimized structure to the combustion of medium-heat value gas was verified.(2)Simplify the prototype combustion chamber model,and get a simplified model with fewer grids and better fit.The ignition process of a gaseous fuel combustion chamber is simulated,and its flame propagation dynamic characteristics are analyzed,which has guiding significance for the research of ignition characteristics.(3)The influence of excess air coefficient on the ignition and hot jet characteristics of the igniter is studied by changing the parameters of the igniter inlet.The ignition boundary of natural gas and medium-heat value gas is obtained,and the reasons for ignition failure when the ignition boundary is exceeded are analyzed;the temperature,velocity,and velocity of the hot jet injected from the igniter into the flame tube on the left and right sides under different excess air coefficients are compared.The parameters such as the energy of the hot jet have obtained the maximum excess air coefficient value which is conducive to the stable ignition of the combustion chamber.(4)The influence of excess air coefficient on the ignition and combustion characteristics of the flame tube was studied by changing the parameters of the flame tube inlet.The effective ignition range of the combustion chamber is obtained,and the reasons for ignition failure are analyzed.On this basis,the combustion characteristics of the flow field in the flame tube under different excess air coefficients were studied,and the optimal value range of the flame tube excess air coefficient was obtained.In this range,the flame tube has higher combustion efficiency,and at the same time avoids the problem of nozzle ablation caused by center flow backfire.