An Analytical and Experimental Investigation of the Annular Injection of Helium Into a Supersonic Air Core

An Analytical and Experimental Investigation of the Annular Injection of Helium Into a Supersonic Air Core
Author: Clarence Albert Kemper
Publisher:
Total Pages: 208
Release: 1962
Genre:
ISBN:

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When a lightweight gas is injected into the boundary layer of a high-speed air flow, the adiabatic wall temperature is reduced by means of a change in properties of the gas in the region where viscous dissipation occurs. The paper summarizes some of the results of a controlled experiment in which helium was injected through an annular slot and along the impermeable surface of a 1.46 inch diameter tube in which a supersonic air stream was flowing at a Mach number of about 4.8. A discussion of some of the analytical results which were obtained is also given. The experimental portion of the investigation included the development of miniaturized boundary layer instrumentation capable of measuring velocity, temperature, and concentration profiles of the flow.

Experimental Investigation of Transverse Supersonic Gaseous Injection Enhancement Into Supersonic Flow

Experimental Investigation of Transverse Supersonic Gaseous Injection Enhancement Into Supersonic Flow
Author: Mark P. Wilson
Publisher:
Total Pages: 159
Release: 1996-12-01
Genre: Airplanes
ISBN: 9781423583189

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In pursuit of more efficient and effective fuel-air mixing for a SCRAMJET combustor, this study was conducted to investigate relative near field enhancements of penetration and mixing of a discrete low-angled (25 deg) injected air jet into a supersonic (M=2.9) cross flow. The enhancements were achieved by injecting the transverse air jet parallel to the compression face of eight different ramp geometries. The jet-ramp interactions created collinear shock structures, baroclinic torque vorticity enhancement, ramp spillage enhanced vorticity, magnus effect penetration enhancement, and increased total pressure loss. Shadowgraph photography was used to identify the shock structures and interactions in the flow field. Measurements of mean flow properties were used to establish the jet plume size, jet plume penetration and to quantify the total pressure loss created by the ramps. Rayleigh-Mie scattering images were used for both qualitative flow field assessments and quantitative analysis of the plume trajectory and mixing rate. Results indicate that up to a 20% increase in penetration height and plume expansion can be achieved by injection over a ramp compared to simple transverse injection. This increase in penetration and mixing incurs up to a 15% loss in total pressure. The most critical geometric aspects that affect the flow are the ramp compression face shape and frontal aspect, and the location and strength of ramp generated expansion.

Design and Evaluation of a Facility to Study Two-Dimensional Supersonic Air-Helium Mixing

Design and Evaluation of a Facility to Study Two-Dimensional Supersonic Air-Helium Mixing
Author: John D. Carlile
Publisher:
Total Pages: 47
Release: 1978
Genre:
ISBN:

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A facility to study two-dimensional supersonic air-helium mixing in a gas dynamic laser cavity was designed, constructed, and evaluated. The flow field may be analyzed via static and total pressure measurements, gas mixture samples, and schlieren photography. The multiple nozzle test section consisted of Mach 3.0 air nozzles alternated with Mach 3.0 helium nozzles exhausted into an instrumented test cavity. Pressure was maintained in the cavity by two alternate methods; simple diffusers exhausted to atmospheric conditions, and exhausting the cavity into a group of evaculated air tanks. Both methods gave similar cavity flow fields as indicated by schlieren photography and static pressure measurements. Gas samples and pressure measurements were taken with a series of small diameter probes and automatically timed solenoid valves. Gas samples were not analyzed in this study. Nozzle exit plane Mach numbers were calculated from pressure measurements and verified with schlieren photographs of a wedge inserted into the flow. The apparatus has low helium consumption and yields accurate, repeatable pressure measurements. The facility is to be used for a subsequent complete flow field analysis. (Author).