Study On Ignition Characteristics Of Closed Cycle Diesel Engine Using Liquid Oxygen To Solidify Carbon

The circulating system of Closed Cycle Diesel Engine Using Liquid Oxygen to Solidify Carbon（LOSCCCD Engine）is completely closed,with no gas exchange,no exhaust emissions,and no harm to the operator who uses a diesel engine in closed environment.However,there are still some deficiencies in the research of the basic theory.Especially the problem of diesel ignition and combustion is the key to the study of new diesel engine combustion mode.It is of great significance to study its ignition characteristics for the development of LOSCCCD Engine.In order to study the ignition characteristics of LOSCCCD Engine,this paper combines simulation and experiment to carry out the research.Firstly,because the ignition delay time is the important ignition characteristic of diesel fuel,the computational formula of ignition delay time is theoretically deduced,and then the KIVA-CHEMKIN simulation platform is established and the simplified mechanism is coupled.Then the combustion process of diesel fuel in the air environment and O₂/CO₂ environment is simulated by KIVA-CHEMKIN simulation platform.Secondly,the visual test platform of constant volume combustion bomb is built,and the combustion process of diesel fuel under air environment and O₂/CO₂environment is studied by visual experiments.Finally,the simulation and test results of diesel fuel are compared and analyzed,the ignition process of diesel fuel in air environment and O₂/CO₂ environment is described,and then the experimental value and simulation value of ignition delay time in air environment and O₂/CO₂ environment are compared and analyzed.The cloud diagram of flame temperature obtained by simulation is analyzed,and the variation of flame lift-off length in air environment and O₂/CO₂ environment is compared and analyzed.The results show that the diesel ignition delay time the ignition delay time,flame temperature cloud diagram and flame lift-off length of diesel fuel under O₂/CO₂ environment are in good agreement with the experimental values.The accuracy of the KIVA-CHEMKIN model for diesel ignition under O₂/CO₂ environment is preliminarily proved.The ignition delay time of diesel fuel in O₂/CO₂ environment is shorter than that in air environment.The flame lift-off length of diesel fuel in O₂/CO₂ environment is obviously smaller than that in air environment.The ignition characteristics of diesel fuel in O₂/CO₂ environment are quite different from those in conventional air environment.The research results in this paper provide an important scientific basis and theoretical support for further research on LOSCCCD Engine.