Accession Number:

ADA083246

Title:

Theoretical Performance Limits for Non-Static Ejector Thrust Augmentors

Descriptive Note:

Final rept. Feb-Sep 79

Corporate Author:

AIR FORCE AERO PROPULSION LAB WRIGHT-PATTERSON AFB OH

Personal Author(s):

Report Date:

1980-01-01

Pagination or Media Count:

55.0

Abstract:

An analytical study was performed to determine the theoretical limits on the performance of non-static ejector thrust augmentors. Idealizing assumptions were made, such as inviscid compressible working fluids, isentropic flows in inlets, diffusers, nozzles and ducts, constant pressure mixing, and thermally and calorically perfect fluids. By ignoring details of the primary flow pump, the performance of ejector augmentors was found in terms of three parameters the secondaryprimary mass flow ratio, a pressure parameter and a temperature parameter in a form which was not an explicit function of the flight Mach number. It was also shown that multi-stage ejectors offered no performance improvement over ideal single-stage ejectors. Two primary pump devices, a turbine engine gas generator and an isentropic compressor, were considered. With them, the Mach number dependent behavior of ideal ejectors was determined. As a result of this study, the following conclusions were drawn 1 The performance of ideal ejector is severely degraded by increasing the primary fluid temperature, 2 the performance of ideal ejectors is degraded faster than that of ideal turbofans as the flight Mach number is increased, 3 Neither the turbine engine nor the isentropic compressor is a suitable pump for ideal ejectors, except at very low Mach numbers, and 4 Ejector augmentors should be most useful for low flight speed applications e.g., VSTOL. Author

Subject Categories:

  • VSTOL
  • Jet and Gas Turbine Engines

Distribution Statement:

APPROVED FOR PUBLIC RELEASE