Preliminary air-flow and thrust calibrations of several conical cooling-air ejectors with a primary to secondary temperature ratio of 1.0. II :diameter ratios of 1.06 and 1.40

Greathouse, W. K., Hollister, D. P.
naca-rm-e52f26
1952


An investigation was made of the performance of nine conical cooling-air ejectors at primary jet pressure ratioes from 1 to 10, secondary pressure ratios to 4.0, and a temperature ratio of unity. This phase of the investigation was limited to conical ejectros having shroud-exit to primary-nozzle-exit diameter ratios of 1.06 and 1.40, with several spacing ratios for each. The experimental results indicated that the pumping range and amount of cooling-air flow obtained with a 1.06-diameter-ratio ejector were relatively small for cooling purposes but that the maximum possible thrust loss, which occurred with no secondary flow, was only 7 percent of convergent-nozzle thrust. The 1.40-diameter-ratio ejector produced a large cooling-air flow and showed a possible thrust loss of 29.5 percent with no cooling-air flow. Thrust gains were attained with ejectors of both diameter ratios at secondary pressure ratios greater than 1.0. The limiting primary pressure ratio below which an ejector can operate at a specific secondary pressure ratio (cut-off-point) may be estimated for various flight conditions from data contained herin.

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