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Opportunity at Air Force Research Laboratory (AFRL)

Low-Power Fiber-Coupled Optical Diagnostics for Hypersonic Flow

Location

Aerospace Systems Directorate, RQ/Airbreathing Propulsion

RO# Location
13.30.01.B8029 Wright-Patterson AFB, OH 454337542

Advisers

Name E-mail Phone
Brown, Michael michael.brown.191@us.af.mil 937.656.6821
Donbar, Jeff M jeffrey.donbar@us.af.mil 937-255-1996

Description

The current state-of-the-art in hypersonic air-breathing propulsion system development relies heavily on a combination of ground tests and numerical simulations. Generally, wall measurements (e.g., pressure, temperature, and heat flux) dominate the instrumentation suite available in most ground test facilities. If in-stream information (typically pitot pressure) is available, it is usually sparse and is generally available only at the inflow and outflow planes of the test article. While valuable for various analyses, these types of information provide little or no detailed descriptions of the mean and turbulent velocity fields, the turbulence-chemistry interactions, or the local state properties within the device. Advanced optical diagnostics are needed for in situ measurements of the parameters (and others) with both temporal and spatial resolution. Preferred diagnostic approaches will use low-power fiber-coupled light source and detector hardware strategies that have an evolutionary path to flightworthy sensors. The research will investigate all aspects of optical diagnostic development for hypersonic flows in scramjet inlets, isolators, and combustors. These aspects include use of novel advanced light source and fiber technology, rapid signal processing for real-time feedback to operators, approaches to tomography, detailed comparison with advanced computational fluid dynamics efforts, and integration into engine control strategies. Specific optical processes to be considered include (but are not limited to) absorption, dual-beam shadowgraphy, and scintillation.

 

Reference

Crow AJ, Boyd ID, Liu J, Brown MS: "Thermal Radiative Simulations and Measurements of the HIFiRE Direct Connect Rig," Journal of Propulsion and Power, (2014), http://arc.aiaa.org/doi/abs/10.2514/1.B35207

 

Keywords:
Hypersonics; Scramjets; Diode laser; Fiber optics; Molecular absorption; Tomography; Scintillation;

Eligibility

Citizenship:  Open to U.S. citizens
Level:  Open to Postdoctoral and Senior applicants
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