Characterization of Combustion Processes of Fuel Sprays Injected into High-Temperature and High-Speed Airstream

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An experimental study was conducted on the characterization processes of kerosene sprays injected into a high-temperature and high-speed airstream. The interior of the combustor has a rectangular cross-section of 70mm x 70mm. A bluffbody with a rectangular shape was settled at the center of the cross section of the combustor which was a certain distance(mixing distance)down the airstream from the nozzle. The experiment in this year was made of the combustion of four sprays injected from each side of the combustor. A distribution of the sprays in the airstream was changed by the location of the nozzle on each side of the combustor. Main results obtained are as follows.(1)A critical kerosene flow rate for flame blow off was decreased and then increased with the airstream temperature, but the variation was small.(2)Spontaneous ignition of the sprays at the mixing distance(between the swirl nozzles and the bluff body)was found when both the airstream temperature and the kerosene flow rate were high. A decrease in a critical kerosene flow rate for the spontaneous ignition with an increase in the airstream temperature made stable combustion range narrow.(3)Relatively homogenizing a distribution of the sprays in the combustor increased the critical kerosene flow rates for both the flame blow off and the spontaneous ignition. A stable combusion range was made wide since the increase with the airstream temperature in the critical kerosene flow rate for the spontaneous ignition was larger than that for the flame blow off.(4)The mixing length did not have a large effect on the critical kerosene flow rate for the flame blow off. An increase in the mixing length reduced the critical kerosene flow rate for the spontaneous ignition.