The Schladitz Fuel Injector: An Initial Performance Evaluation without Burning.

Past tests of the Schladitz Fuel Injector SFI, a network of electrically-heated, extremely-thin metal whiskers, have shown that very fine fuel droplet sprays are formed leading to substantial improvements in combustion efficiency. Evaluation of this performance potential, however, requires thorough investigation of the flow ratepressure dropheating rate influences on spray quality and droplet size distribution. Such tests were performed on two SFI geometries with steady flows of Jet-A fuel. When these flows were discharged directly to the atmosphere, pressure drop reached a minimum at heating rates of 280 Jcc. At this point, spray quality improved noticeably, showing substantial fog or mist production, which became complete mist as the heating rate approached three-fourths the Jet-A enthalpy of vaporization. Similar tests of SFI flows exhausting through conventional spray nozzles showed appreciable improvement in spray quality, producing 50 or more mist at heating rates about one-third less than those required in the absence of nozzles. This improvement was essentially independent of the type nozzle employed, and all nozzle pressure drops were much less than those of the SFI. Droplet size investigations included examination of spray samples on soot-coated slides and observations of laser light absorption.