Accession Number : AD0715642

Title :   An Experimental Investigation to Improve a Jet Mass Augmenter by Means of a Rotating Input.

Descriptive Note : Technical rept.,

Corporate Author : PRINCETON UNIV N J DEPT OF AEROSPACE AND MECHANICAL SCIENCES

Personal Author(s) : Kaufman,Kenneth

Report Date : NOV 1970

Pagination or Media Count : 94

Abstract : The report is concerned with an experimental investigation of an air-to-air jet mass augmenter having a rotating primary flow input. Foa and Hohenemser have predicted that such a device should have a greater performance and a shorter mixing tube than a comparable normal jet augmenter. To determine the validity of this hypothesis, a jet augmenter having a constant area mixing tube and a connection for either a steady or a rotating primary flow nozzle was built and tested. The three rotating primary flow nozzles had geometric spin angles of 0 (steady), 10, and 20 deg from the thrust axis; the coning angle of each was 10 deg. For each experimental configuration, the effect on the agumentation properties and efficiency produced by varying the primary to secondary flow stagnation pressure ratio and the exit plane (back) pressure was determined. The resulting performance of the various augmenters was then compared. Results of the tests show moderate increases in performance for the rotating jet augmenter over the non-rotating. There is a preferred primary flow spin angle yielding the maximum performance for a given geometric configuration; the 10 deg spin angle nozzle gave the best results in these tests. Static pressures measured along the mixing tube wall indicate that the rotating augmenter can operate with a mixing tube length to diameter ratio about 60% less than that of a steady augmenter. Reasons for the performance are discussed. (Author)

Descriptors :   (*THRUST AUGMENTATION, NOZZLES), (*NOZZLES, ROTATION), JETS, NOZZLE GAS FLOW, CONFIGURATION, AIR, BOUNDARY LAYER CONTROL

Subject Categories : Aerodynamics
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE