Experimental Investigation of a Large-scale, Two-dimensional, Mixed-compression Inlet System

Experimental Investigation of a Large-scale, Two-dimensional, Mixed-compression Inlet System
Author: Norman D. Wong
Publisher:
Total Pages: 68
Release: 1971
Genre: Jet engines
ISBN:

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A large-scale, variable-geometry inlet model with a design Mach number of 3.0 was tested at Mach numbers from 1.55 to 3.2. Variable features of the inlet for off-design operation are an adjustable-height ramp system and a translating cowl. This report presents experimental results for a diffuser and boundary-layer bleed configuration which was optimized at the design Mach number. Overall performance was high with throat-mounted vortex generators, which were effective in reducing flow distortion in the subsonic diffuser at the higher Mach numbers.

Tests of a Mixed Compression Axisymmetric Inlet with Large Transonic Mass Flow at Mach Numbers 0.6 to 2.65

Tests of a Mixed Compression Axisymmetric Inlet with Large Transonic Mass Flow at Mach Numbers 0.6 to 2.65
Author: Donald B. Smeltzer
Publisher:
Total Pages: 196
Release: 1972
Genre: Aerodynamics, Transonic
ISBN:

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A 38.8-cm (15.28-in.) capture diameter model of a mixed-compression axisymmetric inlet system with a translating cowl was designed and tested. The internal contours, designed for Mach number 2.65, provided a throat area of 59 percent of the capture area when the cowl was retracted for transonic operation. Other model features included a boundary-layer removal system, vortex generators, an engine airflow bypass system, cowl support struts, and rotating rakes at the engine face. All tunnel testing was conducted at a tunnel total pressure of about 1 atm (a unit Reynolds number of about 8.53 million/m at Mach number 2.65) at angles of attack from 0 deg to 4 deg. Results for the following were obtained: total-pressure recovery and distortion at the engine face as a function of bleed mass-flow ratio, the effect of bleed and vortex generator configurations on pressure recovery and distortion, inlet tolerance to unstart due to changes in angle of attack or Mach number, surface pressure distributions, boundary-layer profiles, and transonic additive drag. At Mach number 2.65 and with the best bleed configurations, maximum total pressure recovery at the engine face ranged from 91 to 94.5 percent with bleed mass-flow ratios from 4 to 9 percent, respectively, and total-pressure distortion was less than 10 percent. At off-design supersonic Mach numbers above 1.70, maximum total-pressure recoveries and corresponding bleed mass flows were about the same as at Mach number 2.65, with about 10 to 15 percent distortion. In the transonic Mach number range, total pressure recovery was high (above 96 percent) and distortion was low (less than 15 percent) only when the inlet mass-flow ration was reduced 0.02 to 0.06 from the maximum theoretical value (0.590 at Mach number 1.0).

Investigation of an Axisymmetric Internal Compression Inlet at a Mach Number of about 3.8

Investigation of an Axisymmetric Internal Compression Inlet at a Mach Number of about 3.8
Author: John H. Lundell
Publisher:
Total Pages: 1
Release: 1961
Genre:
ISBN:

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An idealized axisymmetric, all-internal compression inlet was designed for a Mach number of 3.75. The objective of the design was to obtain a steady, one-dimensional transonic flow and a high over-all total-pressure recovery. Boundary-layer removal was employed in the vicinity of the inflection point of the supersonic contour. Static- and total-pressure fluctuations were measured in the transonic flow region. A total-pressure recovery of about 90 percent was obtained with a boundary-layerremoval mass-flow rate of 15 percent of the inlet mass-flow rate. The accompanying root-meansquare total-pressure fluctuation in the throat region was only 1 percent of the free-stream total pressure. The test Mach number was 3.80 and the Reynolds number based on inlet diameter was 2.63 times 10 to the 6th power. (Author).