NASA SBIR 2004 Solicitation


PROPOSAL NUMBER: 04 X6.09-9119
SUBTOPIC TITLE: Space Transportation Test Requirements and Instrumentation
PROPOSAL TITLE: Simulations of Unsteady Effects and Dynamic Responses in Complex Valve Systems

SMALL BUSINESS CONCERN (Name, E-mail, Mail Address, City/State/Zip, Phone)
Combustion Research and Flow Technology,
6210 Kellers Church Road
Pipersville, PA 18947-1020

PRINCIPAL INVESTIGATOR/PROJECT MANAGER (Name, E-mail, Mail Address, City/State/Zip, Phone)
Vineet Ahuja
6210 Keller's Church Road
Pipersville, PA 18947-1020

CFD based analyses are playing an increasingly important role in supporting experimental testing of rocket propulsion systems. The focus of this proposal is towards identifying and characterizing flow induced instabilities in the experimental test facility. Computational simulations will be carried out with advanced turbulence modeling extensions to the hybrid unstructured framework that has been previously shown to accurately and efficiently predict steady flowfields in complex valve configurations used at SSC. The computational framework will be comprehensive to include instabilities ranging from turbulent pressure fluctuations due to vortex shedding in bends and elbows of the piping system to large scale fluctuations due to collapse of vapor cavities in flow control elements such as venturis. Furthermore, the development in this proposal will include prediction of system response such as amplification and attenuation of dominant instability modes from coupling between components. In Phase II of the proposal development will focus on fluid structure interaction, structural vibrations and resonance. This will greatly enhance the current CFD technology utilized for performance analyses of valve and feed based systems and improve the ability to exert flow control, gauge system response, regulate pressure and suppress instabilities in rocket propulsion test facilities.

The proposed Phase I effort followed by subsequent Phase II will result in a commercial CFD tool that will address some of NASA's needs towards developing a capability for reliability and advanced analysis in support of ground testing of rocket propulsion systems. A detailed analysis of valve response and flow modulation will also be possible and an estimation of test facility response flow instabilities can be predicted. Furthermore, the estimation of unsteady pressure loads will provide valuable information from a structural standpoint, thereby improving the life cycle of the propulsion system.

Commercial applications for the predictive CFD tools being developed are very broad and span a whole host of industries including valve and pump manufacturers, power generation, oil and gas, and petrochemical and refining. The CFD tool will play a significant role in identifying hazardous operating conditions and designing control systems for dynamic disturbance mitigation especially since flow instability and structural resonance can touch off relief valves, damage pipe hangers and destroy vacuum seals. The developed software can also cater to transient analyses of heart valve closure and associated problems with cavitation.