A One-Dimensional Procedure for Estimating the Performance of Ejector Nozzles
AIR FORCE AERO PROPULSION LAB WRIGHT-PATTERSON AFB OH
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The exhaust nozzles of modern turbine engines are often configured as ejectors. The turbine exit gas stream functions as the primary or driving flow, while the secondary flow may be ambient or ram air, fan discharge, or accumulated bleed and leakage flows. The procedure described in this paper was developed to provide a quick performance estimate for ejector nozzles at typical in-flight operating conditions. The paper begins with a review of compound compressible flow theory, then shows how the choked mass flow and thereby, the ejector pumping capacity are found. Analysis of unchoked operation is described and thrust equations for choked and unchoked operation are derived. The final section of the paper deals with the prediction of mixed flow performance for both constant pressure and constant area mixing.
- Pumps, Filters, Pipes, Tubing, Fittings and Valves
- Jet and Gas Turbine Engines