Numerical Simulation And Experimental Research On Plasma Ignition And Combustion Enhancement

With the rapid economic development in our country,the demand for energy is growing.In 2016,the external dependence on natural gas consumption in China was 31% and the petroleum was 64.2%,which showed a trend of increasing year by year.Therefore,it is necessary to develop usable energy to replace traditional primary energy combustion,and blast furnace gas generated during blast furnace ironmaking is a good substitute for natural gas.However,blast furnace gas in the combustion process because of the lower calorific value of ignition difficulties,poor combustion stability,prone to stalling and so on.Plasma ignition combustion technology can solve the problem of fuel ignition difficulty and combustion instability.Plasma ignition combustion technology can not only increase the temperature of combustible mixture flowing through the discharge area,but also produce a large number of active particles to improve the combustion characteristics of the fuel,Thus improving the ignition reliability and combustion stability of the combustion chamber.In this paper,a type of plasma igniter is taken as the research object.The basic control equations and supplementary equations describing the combustion field are established.The effects of plasma on the combustion flow field are studied by experiments and numerical simulations,provides the theoretical basis for the design of plasma generator,the main research contents are as follows:(1)The discharge voltage characteristics of the igniter,the development of the fire core,and the emission spectral characteristics of the air ionization plasma were experimentally studied.The relationship between the discharge voltage of the igniter and the size of the fire core with time,the active particle composition in the air ionized plasma was obtained,and the experimental results laid the foundation for the numerical simulation of the plasma ignition process.(2)Numerical simulation of the development process of the size and energy of plasma nucleus.The effects of ignition position,ignition power,ignition frequency,active particle composition and concentration,and plasma jet depth on ignition performance were analyzed based on a certain type of loop-tube combustion chamber system.The results provide guidance on the design and layout of the igniter.(3)Based on Flame D of simple turbulent diffusive jet flame,the effects of different concentration of active particles on the combustion flow field of low calorific value fuel was researched,and the combustion enhancement effect of different concentration of active particles under different fuel value conditions were compared.Finally,The combustion-supporting effect of low heat-value gas fuels is summarized,and the principle of action is analyzed from the perspective of chemical mechanism.