INVESTIGATION OF THREE LOW-TEMPERFlTURE-RATIO COMBUSTOR CONFIGURATIONS IN A 48-INCH-DIAMETER RAM-JET ENGINE

A preliminary evaluation was made of three types of combustor con-figuration in a 48-inch-diameter ram-jet engine in order to select the one with the greatest promise of efficient and stable combustion at low fuel-air ratios and low combustor-inlet pressures. The combustor configurations evaluated include (1) a can-pi loted configuration using a gutter-type flame holder with can-type pilot burners for stability, (2) an annular-piloted configuration using a gutter-type flame holder with an annular pilot burner to provide stability and to serve as a flow divider for confined fuel-air mixing, and (3) a can-type configu-ration using a flow divider for confined fuel-air mixing. No modifi-cations were made to optimize the performance of any configuration. On the basis of this preliminary evaluation at an inlet-air temperature of about 990 ' R, the annular-piloted combustor configuration gave the greatest promise of providing conibustion efficiencies and combustor total-pressure ratios in excess of 0.90 at low fuel-ai