Small Business Innovation Research/Small Business Tech Transfer
Novel Design of Orifice Type Control Element for Mitigating Instabilities
Project Description
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.
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Anticipated Benefits
The commercial market for our product is very large and includes plant installations and industrial facilities that use extensive piping systems such as nuclear power generation, chemical process plants etc. The technology proposed here can play a critical and imminent role in addressing an important safety concern in pressurized water reactors where orifices are used in the emergency core cooling systems (ECCS) in conjunction with throttle valves. Another application of our product is in reciprocating compressors where resonant pulsation in the piping can be managed through the judicious use of a well-designed orifice-type element. In summary our product will provide the needed resistance in the hydraulic flow-path of plant installations/devices in a variety of industries without the flow transients and instabilities that are commonly associated with orifice plates leading to high-performance, high-reliability systems with significantly reduced risk.
The novel orifice type flow control element resulting from this proposal would help alleviate instabilities in liquid rocket propulsion systems and test facilities for rocket engines that usually are initiated or amplified at the orifice plates. Our product will addresses a severe shortcoming in NASA's test facilities since orifices/venturis are commonly used and are quite often responsible for resonance and structural vibrations observed in the piping system. Design of the new control element proposed here can be tailored to provide the required resistance in the flow path without the risk of cavitation or whistling/resonance/vibration in the test loop. The new orifice design can also be used in segmented solid propellant rockets where they can prevent low frequency oscillations from amplifying, thereby keeping thrust levels stable. More »
The novel orifice type flow control element resulting from this proposal would help alleviate instabilities in liquid rocket propulsion systems and test facilities for rocket engines that usually are initiated or amplified at the orifice plates. Our product will addresses a severe shortcoming in NASA's test facilities since orifices/venturis are commonly used and are quite often responsible for resonance and structural vibrations observed in the piping system. Design of the new control element proposed here can be tailored to provide the required resistance in the flow path without the risk of cavitation or whistling/resonance/vibration in the test loop. The new orifice design can also be used in segmented solid propellant rockets where they can prevent low frequency oscillations from amplifying, thereby keeping thrust levels stable. More »
Primary U.S. Work Locations and Key Partners
| Organizations Performing Work | Role | Type | Location |
|---|---|---|---|
| Combustion Research and Flow Technology | Lead Organization | Industry | Pipersville, Pennsylvania |
| Propulsion Research Center University of Alabama in Huntsville | Supporting Organization | Academia | Huntsville, Alabama |
Stennis Space Center
(SSC)
|
Supporting Organization | NASA Center | Stennis Space Center, Mississippi |
Primary U.S. Work Locations
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Alabama
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Mississippi
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Pennsylvania
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This is a historic project that was completed before the creation of TechPort on October 1, 2012. Available data has been included. This record may contain less data than currently active projects.