| In recent years,as the research on new energy and combustion continues to intensify,non-equilibrium plasma combustion technology,as an efficient,clean and energy-saving auxiliary combustion technology,has begun to receive more and more attention from all walks of life.In the reaction system,non-equilibrium plasma can promote the generation of active substances and the mixing process of reactants in the system through thermal,chemical kinetic and transport effects,thus reducing the ignition delay time,increasing the flame propagation rate,widening the combustion limit and reducing pollution,etc.,and thus becomes an important path to solve the problem of small molecule fuel not easy to burn.At present,researchers at home and abroad have carried out a series of fruitful works including plasma-assisted combustion,ignition and catalytic conversion,but there is still a lack of research on the kinetic mechanism of plasma-enhanced fuel cracking and oxidation,especially the mechanism related to ionic reactions,and the research results are mainly focused on carbonaceous fuels such as alkanes,and there are few studies on plasma-assisted combustion of emerging fuels such as ammonia.There are only a few studies on plasma-assisted combustion of emerging fuels such as ammonia.Therefore,this thesis establishes and improves a quasi-1D plasma-assisted ignition platform to investigate the role of ion reactions in methane cracking process;and builds an experimental bench to study the kinetic role of plasma in the oxidative ignition of ammonia using a combination of numerical simulations and experimental studies.The main studies are as follows.(1)Established and improve the plasma simulation platform,including the main program,constant differential equation solver LSODE,reaction rate solver DIFFUN and Boltzmann solver and other parts,and on this basis,modify and optimize the simulation platform,improve the parts of each module involving electron collision reaction and ion reaction according to the ion reaction involving particles in the mechanism,and supplement the thermodynamic data and electron collision cross-section data within the data file,so as to realize further improvement of the platform ion reaction calculation function.(2)A nanosecond pulse discharge-assisted ammonia cracking and oxidation experimental platform was built to experimentally study the plasma-assisted ammonia cracking and oxidation process,and to obtain information on the important groups and the concentration of products in the ammonia cracking and oxidation process by means of spectral measurements and product concentration measurements,so as to verify the accuracy of the established model.(3)To establish the plasma-assisted methane cracking reaction mechanism and calculate it by using the simulation platform,to study the kinetic process of cracking by analyzing the generation and consumption of important substances,and to add and change the important ion reactions in the mechanism,and to study the role of ion reactions in the plasma-assisted methane cracking process by changing the concentration of the main products before and after adding ion reactions.(4)Establishment of plasma-assisted methane oxidation ignition mechanism.The effects of plasma on the characteristic parameters of ammonia ignition and the kinetic process of assisted ammonia oxidation at different temperatures and approximate electric field strengths are investigated to determine the discharge conditions corresponding to the maximum effect of non-equilibrium plasma on ammonia ignition enhancement.And based on the analysis results,the effects of the approximate electric field strength and doped hydrogen on the ammonia oxidation process are investigated. |
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