Analyses And Design Of Gas Sampling System To The Direct-connect Supersonic Combustor Testing

In the development of scramjet, evaluating of the combustor’s performance wasbecoming more and more important. Among the several method to evaluate thecombustor’s performance, the gas sampling method was received the extensiveattention and application, because of its simple configuration, common material andquantifiable production analyses.This paper focused on the design of the gas-sampling probe’s configuration. Theinternal flow area of the probe was considered as a one-dimensional process withchemical reaction, heat transfer, and variable area. The gas sampling is based on theassumption that the gas composition is frozen in the sampling process, which need ahuge temperature decrease and the nice flow performance before the probe. Theinvestigation was conducted by the way of combined the CFD method with theexperimental method. Finally, the gas sampling probe is designed, including theforepart with a semiapex angle of30degree, a inner flow path with an entrancediameter of0.8millimeter (a length of6mm), then expanded to diameter of4mm.After have determined the configuration of the probe, we designed the matchedgas sampling system, which was mounted at the exit of the combustor. The gassampling was constructional of the gas sampling probe, the gas sampling base, waterpump, vacuum pump, electromagnetism valve, flange plate and the gas samplingsyringe.When finished the design of the gas sampling system, it was the time to go on thecalibration experiment. The calibration experiment was conducted on the designedsystem to demonstrate its safety and feasibility. There were two kinds calibrationexperiment, one was the air calibration experiment,and the other one was no fuelcalibration experiment. In the end, the results showed that the gas sampling systemwas succeed in sampling the high temperature burning gas and rapidly freezing thechemical reaction.