Novel Design of Orifice Type Control Element for Mitigating Instabilities

Award Information
Agency: National Aeronautics and Space Administration
Branch: N/A
Contract: NNX11CI43P
Agency Tracking Number: 100023
Amount: $99,971.00
Phase: Phase I
Program: STTR
Awards Year: 2011
Solicitation Year: 2010
Solicitation Topic Code: T10.01
Solicitation Number: N/A
Small Business Information
Combustion Research and Flow Technology
PA, Pipersville, PA, 18947-1020
DUNS: 929950012
HUBZone Owned: N
Woman Owned: N
Socially and Economically Disadvantaged: N
Principal Investigator
 Vineet Ahuja
 Principal Investigator
 (215) 766-1520
Business Contact
 katherine Young
Title: Business Official
Phone: (215) 766-1520
Research Institution
 Propulsion Research Center University of Alabama in Huntsville
 David Lineberry
 S225 Technology Drive
Huntsville, AL, 35899-0001
 () -
 Federally funded R&D center (FFRDC)
An orifice element is commonly used in liquid rocket engine test facilities either as a flow metering device, or to provide a large reduction in pressure over a very small distance in the piping system. While the orifice as a device is largely effective in stepping down pressure, it is also susceptible to a wake-vortex type instability that generates pressure fluctuations that propagate downstream and interact with other elements of the test facility resulting in structural vibrations. Furthermore in piping systems an unstable feedback loop can exist between the vortex shedding and acoustic perturbations from upstream components resulting in an amplification of the modes convecting downstream. Such was the case in the Arianne 5 strap-on P230 engine in a static firing test where pressure oscillations of 0.5% resulted in 5% thrust oscillations. The innovation described in this proposal directly relates to a proprietary design of a step down orifice that inhibits the instability modes generally associated with the operation of a traditional orifice while meeting performance guidelines. In the Phase I effort we will demonstrate the effectiveness of the new device through a combination of analysis and sub-scale testing in a cryogenic environment.

* information listed above is at the time of submission.

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