Further Evaluation of Blast Tests of an Engine Inlet.
Abstract
A test program was conducted to simulate blast wave intercepts with a scaled aircraft engine in subsonic flight. Initial results were reported in DNA 4590F. This report presents additional test data and evaluated results. Jumps in total pressure at the engine face produced by blast interaction with the blastward and leeward inlets are evaluated with respect to effects of four test variables: inlet weight flow, Mach number, shock overpressure and intercept angle. The total pressure rose more rapidly in the blast inlet than the leeward inlet, following the blast intercept, and by a larger amount. In many tests the rise in the leeward inlet was followed by a rapid fall-off, indicating possible flow separation in the inlet walls. The two-dimensional Blast Induced Distortion (BID) code provides good representation of effects essentially two-dimensional and inviscid, such as ramp, cowl and engine-face pressures of the blastward inlet. Blast wave reflection from the engine is expected to be a potential cause of distortion through boundary-layer retardation. The effect on engine-face total pressure is examined with respect to the four test variable. Improved calculations of the effect of the engine-reflected blast wave on the boundary layers in the inlets, made using the generalized NASA-Lewis BLAYER code, indicate that the boundary-layer separation would result. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 31, 1979
- Accession Number
- ADA088511
Entities
People
- J. Ray Ruetenik
- Michael A. Tomayko
- Robert F. Smiley