A Shock Tube Study Of Ignition Delay Characteristics Of Ethylene

Ethylene is an olefin hydrocarbon fuel of internal combustion engine, gas turbine engines and other propulsion equipment, but also the important small molecule product of the hydrocarbon fuels’ thermal cracking process. Therefore, the study of ignition delay of the ethylene has an important meaning to set up the reaction kinetics model of hydrocarbon fuel ignition.Ignition time studies have been conducted using a variety of different experimental methods, such as jet-stirred reactors, continuous flow reactors, rapid compression machines, constant volume bombs, and shock tubes. Since the shock tube which has a simple structure, no power supply, no cooling system, and can easily heat, pressure and speed the gas to the high parameter, it has been widely used in ignition delay research. This thesis will study the ignition delay characteristics of ethylene at high argon dilution and different temperatures, pressures, ratio condition. The main work is done as follows. First of all, we set up a shock tube experiment platform based on the existing experiments plant design parameters. It is consisted of shock tube, gas distribution system, pressure measurement system and spectroscopic measurement system. Shock tube includes a tube body and the support system; gas distribution includes the high-pressure premixed gas chamber, low-pressure premixed gas chamber, cylinder, vacuum pump group, manometers, vacuum gauges, valves and piping and other components; pressure signal was picked by the pressure electric sensor acquisition, through the charge amplifier, and collected by oscilloscope acquisition; spectroscopic measurement system includes a filters, a monochromator, and a photomultiplier tube. And then we written a LABVIEW simulation interface based on the ideal shock tube operating parameters calculate formula. Combine the simulation interface, we have conducted the incident shock Mach number calibration experiments, incident shock wave attenuation rate measurement experiment, suture contact surface running experiment, completed the commissioning of the shock tube experiment platform to prepare for the ignition delay experiments. Finally, the ignition delay characteristics of the ethylene/O₂/Ar mixture were measured with the indication by the steepest rise of the characteristic emission from CH radical at 432 nm. The experimental conditions cover pressures at 1.5atm and 6atm, equivalence ratio of 0.5、1.0 and 3.0, and temperature range from 1050 to 1700 K, respectively. The impact of the pressure and equivalence ratio on ignition delay characteristics of ethylene was investigated. The dependence relation of the ignition delay time of ethylene with temperature, pressure, stoichiometric ratio, fuel concentration, oxidant concentration and other parameters was obtained by least squares fitting as follows:...