Accession Number:

AD0767712

Title:

Experimental Investigation of an External Aerodynamic Diffuser,

Descriptive Note:

Corporate Author:

WEST VIRGINIA UNIV MORGANTOWN DEPT OF AEROSPACE ENGINEERING

Personal Author(s):

Report Date:

1971-04-01

Pagination or Media Count:

96.0

Abstract:

Improvement in the thrustpower ratio for shrouded propellers and fan-in-wing units, which are widely used for VSTOL aircraft propulsion, can be achieved by using an external aerodynamic diffuser during hover. Large diffuser divergence angles are required which necessitate a technique of controlling the flow separation from the internal diffuser wall. The purpose of this experimental investigation was to obtain a correlation between experimental and analytical prediction of performance improvement in order to generate a design technique for optimization of external diffusion, and investigate the potential of several techniques which offer a method of forcing the flow to diffuse externally. A static test facility for measuring the external flow field and the thrust of the model was constructed. All tests were performed with uniform, axial flow at the diffuser inlet. Two-dimensional tests were conducted employing either turning vanes, coanda effect, or rotating cylinder walls. Axisymmetric tests were performed using boundary layer control by suction or blowing. Modified author abstract

Subject Categories:

  • Aerodynamics
  • VSTOL
  • Jet and Gas Turbine Engines

Distribution Statement:

APPROVED FOR PUBLIC RELEASE