Contrails
The goal of the Contrails project is to help preserve and disseminate the technical record of 20th century aerospace research, highlighting in particular the research endeavors of the Illinois Tech community.

Characteristics of High Performance Ejectors

Report Number: AFWAL TR 81-3170
Author(s): J. E. Minardi
Corporate Author: University of Dayton Research Institute
Laboratory: Flight Dynamics Laboratory
Date of Publication: 1982-01-01
Pages: 99
Contract: F33615-81-K-3017
Project: 2404
Task: 240410
AD Number: ADA118720

Abstract:
The use of ejectors in energy conversion processes and thrust augmentation requires that the mixed flow be produced at a high efficiency. Although many definitions of efficiency have been used to describe the efficiency of an ejectors, we have used an efficiency based on thermodynamic availability which is referenced to the stagnation properties of the secondary flow (the flow being 'pumped'). As is well known, a compressible-flow, control-volume approach to analyzing a constant area ejector yields two solutions: one with a subsonic mixed flow and one with a supersonic mixed flow. The supersonic mixed flow produces the best efficiencies and highest total pressures. The properties of the supersonic mixed flow are of necessity related to the properties of the subsonic mixed flow by the normal shock relations. Nonetheless, in practice, the subsonic mixed flow is, in general, not achieved through a normal shock (or pseudo-normal shock) from the supersonic mixed flow solution. A model is presented that gives a physical interpretation to the various solutions obtained from the mathematics, and more importantly, some fundamental limits are presented and a procedure is developed for determining the efficiency that can be achieved in a constant area ejector when the mixed flow is supersonic.

Download this report

(PDF, 1.9 MB, 99 pages)

Other options for obtaining this report

Via the Defense Technical Information Center (DTIC):
A record for this report, and possibly a full-image download of the report, exists at DTIC

Via National Technical Information Service:
This report may have been digitized and made freely available for public download, or made publicly available for purchase by the National Technical Information Service through their online database, the National Technical Reports Library

Indications of Public Availability
No digital image of an index entry indicating public availability is currently available
There has been no verification of an indication of public availability from an inside cover statement