The HCCI Numerical Simulation Of Ammonia Based On Chemical Reaction Kinetic

With the improvement of science and technology, more and more people begin topay attention to the new energy and the new combustion mode research in internalcombustion engine. In recent years, ammonia as a new fuel is gradually appear in theresearchers’ line of sight and it is considered to be a more promising alternative fuel.The research about ammonia which used as the fuel of internal combustion engine isstill in the primary stage and mainly by experimental method. The properties ofammonia fuel obtained by test method are all the result under the specific conditions,can’t reflect the general characteristics of ammonia. The simulation of ammoniacombustion in HCCI engine by using mechanism of ammonia fuel can get it’s generalcharacteristics, and provide a theoretical basis for the better application of ammonia.This research based on homogenous compression combustion ignition enginemodel in gas dynamics software CHEMKIN, first of all to find the suitable ammoniacombustion oxidation mechanism to couple with the model of engine. The resultscalculated on the combustion performance were analyzed and get the advantages anddisadvantages of the ammonia combustion performance, also analysis of path ofcombustion and emission performance of ammonia. Finally, put forward theimprovement measures of ammonia based on analysis of ammonia combustionperformance, analysis the role of pilot fuel in the combustion, and compared the effectof the pilot fuel when select different molar percentage n~heptanes, get its effect onignition timing, compression ratio, inlet air temperature and the content of pollution.Through the analysis on present situation of ammonia fuel and HCCI combustionmethod, find out and compared different ammonia oxidation mechanism which got bydifferent researchers, and select the simplified Konnov ammonia oxidation reactionmechanism improved by Catherine, the mechanism contains19kinds of chemicalcomponents and80reactions. The coupling mechanism and model of internalcombustion engine can get the calculations model of the internal combustion engine,the engine model used to calculate the effect of different intake temperature, intake airpressure, compression ratio, speed of engine and excess air factor relations ontemperature and pressure in cylinder, by the analysis on the result we can get thecombustion performance of ammonia fuel. At the same time, calculation of nitrogenoxygen compounds changes with the crank angle, analysis emission performance of NH3under different conditions. Then analysis the effect of different EGR rate onammonia fuel combustion and emission performance.Found ammonia fuel higher ignition point through the analysis of the combustionperformance, if want to use ammonia in a compression ignition engine as fuel needshigher intake air temperature and compression ratio, so some measures needed toimprove the combustion properties of ammonia fuel. Add n~heptanes which has lowerignition point in ammonia fuel as the pilot fuel, analyze the role of ignition fuel on theammonia fuel combustion. the mixed fuel’s combustion oxidation mechanism shouldbe establish in the simulation, and its coupled with the engine model, get mixturecompression ignition internal combustion engine model. The temperature in cylinder,pressure in cylinder and emissions changes with the crank angle relationship can becalculated by the new model under different percentages n~heptanes.