Accession Number : ADA323966

Title :   Applicability of Thrust Augmenting Ejectors in a Supersonic Cruise Configuration.

Descriptive Note : Master's thesis,

Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSONAFB OH

Personal Author(s) : Hertzelle, Wendell S.

PDF Url : ADA323966

Report Date : 18 APR 1997

Pagination or Media Count : 92

Abstract : Thrust augmenting ejectors were analyzed by the author in an attempt to see if they could be used to provide a significant thrust increase over the baseline thrust of a primary core. This was done for the purpose of determining if leaving the ejectors open in the cruise configuration of the High Speed Civil Transport would lead to a thrust increase that would at least offset the weight of the ejectors themselves. If this was found to be true then the fuel economy of the HSCT might be improved by leaving them open and not closing them during cruise. In analyzing the ejectors, no assumptions were made regarding inlet nor outlet configurations, so an attempt was made to find the point of optimal thrust augmentation by varying secondary stream bypass Mach number and the amount of flow entrainment. Two solutions were found to each mixing scenario, one subsonic and the other supersonic. These two solutions were each analyzed and ones not satisfying the Second Law of Thermodynamics were eliminated. Analytic diffuser and bleed losses were also explored in the analysis of the ejector flow. Within the limitations of the assumptions discussed in this paper, appreciable thrust augmentations have been discovered over a large range of bypass Mach numbers and entrained mass flows. This lead the author to the conclusion that ejectors warrant further research beyond a first order analysis, and serious thought should be put into leaving them open in cruise.

Descriptors :   *SUPERSONIC FLIGHT, *SUPERSONIC TRANSPORT AIRCRAFT, *THRUST AUGMENTATION, THROTTLING, TURBOFAN ENGINES, OPTIMIZATION, THESES, MASS FLOW, FUEL CONSUMPTION, CIVIL AVIATION, MACH NUMBER, SUPERSONIC FLOW, FREE STREAM, AIR EJECTORS, AIRCRAFT NOISE, JET MIXING FLOW, SUPERSONIC DIFFUSERS, BLEED SYSTEMS, THRUST AUGMENTOR NOZZLES.

Subject Categories : Aerodynamics
      Transport Aircraft
      Jet and Gas Turbine Engines

Distribution Statement : APPROVED FOR PUBLIC RELEASE