Product Code:SAE AIR1191
Title:Performance of Low Pressure Ratio Ejectors for Engine Nacelle Cooling
Issuing Committee:S-12 Helicopter Powerplant Committee
Scope:Method: A general method for the preliminary design of a siingle, straight-sided, low subsonic ejector is presented. The method is based on the information presented in References 1, 2, 3, and 4, and utilizes analytical and empirical data for the sizing of the ejector mixing duct diameter and flow length. The low subsonic restriction applies because compressibility effects were not included in the development of the basic design equations. The equations are restricted to applications where Mach numbers within the ejector primary or secondary flow paths are equal to or less than 0.3.Procedure: A recommended step-by-step procedure is shown.Equations: The equations used in the procedure, as well as their derivations, are given.Sample Calculation: A sample calculation is presented to isllustrate the use of the basic method.