Accession Number : ADA010102

Title :   Study of Wall Jets in Duct Diffuser Systems.

Descriptive Note : Final technical rept. Apr-Sep 74,

Corporate Author : MARTIN MARIETTA AEROSPACE DENVER COLO DENVER DIV

Personal Author(s) : Maegley,Wendel J. ; Lefferdo,James M.

Report Date : FEB 1975

Pagination or Media Count : 70

Abstract : The effectiveness of wall jets in preventing diffuser stall in a simulated two-dimensional thrust augmenter was experimentally investigated. The tests were conducted in the static mode; that is, the flow through the inlet of the model was free from ram-air effects. The velocity of the airflow through the model ranged from 90 to 260 ft/s while the area ratio of the diffuser was systematically varied from 1.73 to 2.72. The wall-jet slot height was varied from 0.05 to 0.196 in. Nitrogen wall jets were found to be an effective means of suppressing stall. For a given diffuser area ratio and wall-jet slot height, the minimum wall-jet mass flow was an almost constant fraction of the primary air mass flow. From the standpoint of power required to suppress stall, larger jets were more efficient.

Descriptors :   *Thrust augmentation, *Diffusers, *Jet flow, Potential flow, Flow fields, Flow separation, Aerodynamic slots, Wing slots, Wind tunnel models

Subject Categories : Aircraft
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE