Analysis and testing of two-dimensional slot nozzle ejectors with variable area mixing sections

Finite difference computer techniques have been used to calculate the detailed performance of air-to-air two-dimensional ejectors with symmetric variable area mixing sections and coaxial converging primary nozzles. The analysis of the primary nozzle assumed correct expansion of the flow and is suitable for subsonic and slightly supersonic velocity levels. The variation of the mixing section channel walls is assumed to be gradual so that the static pressure can be assumed uniform on planes perpendicular to the axis. A test program was run to provide two-dimensional ejector test data for verification of the computer analysis. A primary converging nozzle with a discharge geometry of 3.18 mm x 203 mm was supplied with 0.340 kg/sec of air at about 2.43 bar and 356 K. This nozzle was combined with two mixing section geometries with throat sizes of 31.8 mm x 203 mm and 47.6 mm x 203 mm and was tested at a total of 11 operating points.