Title: Internal performance at Mach number to 2.0 of two auxiliary inlets immersed in fuselage boundary layer
Abstract: NACA RM E531,28bNATIONAL ADVISORY COMMITTEE FOR AERONAUTICSRESEARCH MEMORANDUM INTERNAL PERFORMANCE AT MACH NUMBERS TO 2.0 OF TWO AUXILIARY INLETS IMMERSED IN FUSELAGE BOUNDARY LAYER By Donald B. Pennington and Paul C. Simon SUMMARY An experimental investigation was conducted to evaluate the inter-nal performance of two types of auxiliary air inlets, a submerged and a scoop inlet, operating within the turbulent boundary layer existing on the bottom of a typical supersonic fighter aircraft afterbody. Diffuser-exit total-pressure recovery and mass flow were obtained at stream Mach numbers of 0.64 and from 1.5 to 2.0 at angles of attack of 0 and 30. The maximum total-pressure recovery of the submerged inlet was 0.35 and 0.17 at stream Mach numbers of 1.5 and 2.0, respectively. At these same Mach numbers the scoop inlet critical recovery, 0.45 and 0.27, fell considerably below the theoretically possible values. INTRODUCTION In addition to the engine air-flow requirements of power plants for supersonic vehicles, auxiliary air may be needed for engine cooling and accessory drive purposes. This auxiliary air may be furnished by the engine air source or, in some cases, by one or more independent auxil-iary inlets. Although considerable effort has been expended in studying the per-formance of jet-engine air inlets, little is known about the performance of small, independent auxiliary inlets. The size, type, and location of the auxiliary inlet will vary with the weight flow and pressure level required. Since the weight-flow and pressure-level requirements are usually low, compared with the engine, and since the installed drag should be kept to a minimum, it may be necessary to place such auxil-iary inlets within the fuselage or the wing boundary layer.
Publication Year: 1954
Publication Date: 1954-03-10
Language: en
Type: article
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