STUDY OF COMBUSTORS FOR SUPERSONIC RAM-JET (ODS PROJECT)

Investigation of the air pressure at various points in these burners before combustion started showed that immediately downstream from the flame holder the pressure was below atmospheric and the velocity above sonic. Since it is known that low pressure makes ignition difficult an effort was made to ignite in a zone of higher pressure. This was accomplished by placing two flame holders in series and igniting at the upstream flame holder where the pressure was higher due to the effect of the downstream flame holder. Using this principle, burners capable of spark ignition over a wide range of airfuel ratios at an air rate of 11 lbs.sec. have been developed. These burners develop approximately 80 of theoretical thrust at 151 airfuel ratio and 85 of theoretical thrust at 22.1 airfuel ratio. The air specific impulse is about 150 lbs. per lbs. of airsec. at an airfuel ratio or 151. The actual thrust under these conditions is about 1000-1100 pounds. The drag of the atomizing section, the ignition section and the burner walls, as determined from thrust and pressure measurements during burning at 151 airfuel ratio and 11 lbs.sec. of air, amounts to about 11 of the thrust developed or about 4 p.s.i. for one of the burners.