Investigation of performance of several double-shroud ejectors and effect of variable-area exhaust nozzle on single ejector performance

Ellis, C. W., Hollister, D. P., Wilsted, H. D.

An investigation was made to determine briefly the characteristics of a double-shroud cooling-air ejector. Also, the performance of single-shroud ejector having a clamshell-type variable-area actuating nozzle was compared with that of an ejector having a conical nozzle. For the models investigated, the experimental results indicated that the differences in the variable-area and conical nozzle ejector performance are due primarily to flow restrictions in the cooling passage introduced by the clamshell protrusions, rather than the nonplanar and noncircular exit. The investigation of double-shroud-ejector performance, while not completely general in application, does indicate that an ejector of this type could be designed to operate satisfactorily, that is, with a ratio of tertiary to secondary air weight flow of about 0.2. In order to obtain such performance, the difference between the diameter ratios and spacing ratios of the two shrouds should be small.

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