Characteristics of High Performance Ejectors

Item

Title
Characteristics of High Performance Ejectors
Date
1982
Index Abstract
Coming Soon
Photo Quality
Not Needed
Report Number
AFWAL TR 81-3170
Corporate Author
University of Dayton Research Institute
Laboratory
Flight Dynamics Laboratory
Date Issued
1982-01-01
Extent
99
Identifier
ADA118720
Access Rights
Approved for public release; distribution unlimited
Distribution Classification
1
Contract
F33615-81-K-3017
DoD Project
2404
DoD Task
240410
DTIC Record Exists
No
Distribution Change Authority Correspondence
None
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.
Report Availability
Full text available
Provenance
AFRL/VACA
Type
report
Format
1 online resource
Creator
Minardi, J. E.
Media
AFWALTR81-3170.pdf