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ACTA AERONAUTICAET ASTRONAUTICA SINICA ›› 2015, Vol. 36 ›› Issue (1): 302-310.doi: 10.7527/S1000-6893.2014.0259

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Flow characteristics experiments of a hypersonic axisymmetric inlet with nose bluntness

GAO Wenzhi, LI Zhufei, YANG Jiming   

  1. Department of Modern Mechanics, University of Science and Technology of China, Hefei 230027, China
  • Received:2014-07-31 Revised:2014-09-15 Online:2015-01-15 Published:2014-09-19
  • Supported by:

    National Natural Science Foundation of China (11132010)

Abstract:

Blunt scale of leading edge is a key parameter in the design of hypersonic inlet. Flow characteristics of a hypersonic axisymmetric inlet, of which forebody compression surfaces consisted of a cone and curved surfaces, are studied experimentally at Ma=6 with nose blunt scales up to 3.2 mm (5% cowl lip radius). High speed schlieren imaging of external flow field and centerbody pressure distribution are recorded during experiments, with the model installing angles of attack of 0°, 4° and 7°. Forced transition tests are also explored with trips at angle of attack of 0°. It is shown that the variations of the forebody flowfield and pressure distribution are negligible within 3.2 mm nose radius for the horizontal freestream, while small separation regions exist around the inlet entrance. The tripped cases show obvious suppression of the flow separation, validating successful transition dominated by trips. Obvious discrepancies of nose effects have been found between windward and leeward sides of the axisymmetric inlet under the freestream angle of attack. Variations of windward flowfield and pressure distribution can be hardly noticed for current runs, while slip lines of leeward side move outward and leeward flowfields turn to be unstable with increasing nose scale. For the largest 3.2 mm nose radius, evident separation appears on the leeward side at angle of attack of 4°, corresponding to surface pressure rise in the separation region. The separation becomes more severe when the angle of attack increases and the leeward side of the inlet turns to be unstart at angle of attack of 7°, which results in remarkable pressure drop.

Key words: hypersonic flow, axisymmetric inlet, nose bluntness, freestream angle of attack, flow separation

CLC Number: