| Objective: ||Develop innovative flow diagnostics and engine structure sensors for high speed, air-breathing propulsion system maturation and demonstration in short-duration ground and flight testing.
|| Description: ||Air-breathing propulsion engines to support high-speed flight, above Mach 4, are difficult to mature to desired levels of readiness without the use of in-flight experimentation. The high enthalpy associated with simulating high-Mach conditions results typically in ground-test air that is contaminated with particulates or combustion gas products, or results in steady-state test times that are short -- measured in milliseconds. Also, in ground tests of such engines, high-fidelity simulation of key engine transients, such as ignition and acceleration, is difficult or impossible. Thus, flight testing of hypersonic engines is a crucial part of the development process. Acquisition, processing, and transmission of engine performance, operability, and durability from a flight test, while meeting the standards of a typical ground test, remain challenging. The following, in particular, are areas of interest: local skin friction and heat flux; core flow properties of temperature (T), pressure (P), and species concentrations; and, engine area change. All need to be measured in flight with the accuracy, speed, and spatial density typical of a ground test. This announcement is broad in that focusing on any one or more of these issues is acceptable.
The payoff is making flight testing, even of short duration, a source of high-quality and high-density flow and structure data to complete the development process for high-speed engines, as opposed to a demonstration of fully matured hardware.
|| ||PHASE I: Develop concepts for measuring basic engine performance, operability, and structural integrity. Concepts must enable measurement of a specific parameter (e.g., skin friction or area change) at reasonable accuracy and spatial resolution (specified below), have a tolerance for high temperatures from 425 K within an instrument bay and up to 1,000 K near combustor surfaces, and provide data rates of at least 100 Hz: Target values for measurement error (within quoted value) and spatial dimension/resolution are as follows:
1. Surface skin friction and heat flux: 10% of value; 15 mm<sup>2</sup> surface area.
2. Core T, P, and species concentration: 10% of value; 3 mm, though averaging across duct spanwise dimension is acceptable.
3. Engine flowpath area: detect changes as small as 2% of flowpath area; 25 mm along flowpath axis.
Additional performance targets include the following: lifetime at least 10 minutes during scramjet-powered flight; respective volume and weight of instrument package less than 1 L and 2 kg; power consumption less than 10 Watts.
|| || ||PHASE II: Validate the instrument/sensor in a ground test of an appropriate engine component. Demonstrate the utility/accuracy of the measurement and tolerance to the expected environment. While the instrument/sensor may still be in a bread-board configuration, acceptable data rates and power consumption must be demonstrated. Miniaturization strategy must be confirmed.
|| ||DUAL USE COMMERCIALIZATION: Military application: Success will yield instruments that can be used in any propulsion application: thermal environment and packaging and power consumption requirements of hypersonic propulsion should be the most severe. Commercial application: The primary applications are clearly both military and commercial. Such instrumentation can be applied to certified engines as part of the engine control instrumentation.
|| References: ||1. Yu, Sibok and Newman, Brett, “Development of a high accuracy MEMS angular measurement system for hypersonic wind tunnel facilities,” AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference, Vol. 7, pp. 5168-5178, 2003.
2. Blanchard, R.C., Wilmoth, R.G., Glass, C.E., Merski N.R., Jr., Berry, S.A., Bozung, T.J., Tietjen, A., Wendt, J., and Dawson, D. “Infrared sensing aeroheating flight experiment: STS-96 flight results,” <i>Journal of Spacecraft and Rockets</i>, Vol. 38, No. 4, pp. 465-472, July/August, 2001.
3. Carter, J.S., “A technique for the simultaneous measurement of several hundred heat-flux gages,” Instrumentation in the Aerospace Industry: Proceedings of the International Symposium, pp. 81-89, 1999.
|Keywords: ||scramjet, sheer stress instrumentation, heat flux measurements, data acquisition, hypersonic flight experiment package|