Preliminary air-flow and thrust calibrations of several conical cooling-air ejectors with a primary to secondary temperature ratio of 1.0 I :diameter ratios of 1.21 and 1.10

Greathouse, W. K., Hollister, D. P.
naca-rm-e52e21
1952


An investigation of the performance of several conical cooling-air ejectors was made at primary jet pressure ratios from 1 to 10, secondary shroud pressure ratios from 0.60 to 4.00, and a primary to secondary temperature ratio of 1.0. Primary air flow, secondary air flow, primary nozzle thrust, and gross ejector thrust were measured. The data are presented in terms of secondary to primary weight-flow ratio and gross ejector to primary nozzle thrust ratio. This phase of the investigation was limited to ejectors having shroud-exit to primary-nozzle-exit diameter ratios of 1.21 and 1.10 with several spacing ratios for each. The experimental results indicated that for an ejector having a given diameter ratio, the spacing ratio for maximum thrust was considerably less than the spacing ratio for maximum pumping. The smaller-diameter-ratio ejector produced less thrust loss at secondary pressure ratios below 1.00 than did the large-diameter-ratio ejector. The data indicated that significant losses in gross thrust will occur if the cooling-air flow is controlled by throttling in the upstream secondary flow passage.

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