NASA SBIR 2003 Solicitation


PROPOSAL NUMBER:03-A4.06-9873 (For NASA Use Only - Chron: 033132)
SUBTOPIC TITLE:Launch Vehicle Subsystems Technology
PROPOSAL TITLE:Modeling Unsteady Cavitation Effects and Dynamic Loads in Cryogenic Systems

SMALL BUSINESS CONCERN (Firm Name, Mail Address, City/State/Zip, Phone)
Combustion Research and Flow Technology,
6210 Keller's Church Road
Pipersville ,PA 18947 - 1020
(215) 766 - 1520

PRINCIPAL INVESTIGATOR/PROJECT MANAGER (Name, E-mail, Mail Address, City/State/Zip, Phone)
Ashvin    Hosangadi
6210 Keller's Church Road
Pipersville ,PA  18947 -1020
(215) 766 - 1520
U.S. Citizen or Legal Resident: Yes

There currently are no analytical or CFD tools that can reliably predict unsteady cavitation dynamics in liquid rocket cryogenic systems. Analysis of cavitating cryogenic systems presents a challenge, and is poorly understood, because the phase change process couples with the temperature fluctuations in the fluid. In particular when large scale flow unsteadiness is present at low-flow, off-design conditions, this coupling can lead to significant enhancement of vaporization and possibly lead to cavitation instabilities. These large amplitude, dynamic loads can interact with other system components and cause severe damage. The innovation proposed here is the development of an unsteady numerical framework that can predict amplitudes and frequencies of dynamic pressure loads in cryogenic fluids. This innovation will address the inclusion of advanced unsteady cavitation models, validation for pressure fluctuations in cryogenic fluids, and development of unsteady boundary conditions for coupling the turbopump to other system components. An experimental program will be set up in the Phase II effort to obtain unsteady flow data for code validation. The resulting product, a specialized version of the multi-element unstructured CRUNCH CFD code, will be a well-validated and reliable analysis tool that can be used to predict unsteady, off-design performance of liquid rocket turbopumps.

The proposed effort directly impacts NASA?s NGLT program. Next generation liquid rocket systems under consideration envision novel designs for turbopumps that can be throttled over a wide range of low, off-design flow conditions; an extremely demanding flow regime where performance loss and damage from cavitation instabilities can be catastrophic. There are currently no reliable means to predict detailed three-dimensional flow parameters required to analyze system safety. Hence, the proposed advanced CFD tool, that will be well-validated against detailed experimental data, can play a role in both analyzing and optimizing designs for improved performance and safety of cryogenic turbopump systems.

This product will impact commercial applications in two areas: 1) modeling specialty pumps (e.g. refrigerant systems, chemical pumps for volatile fluids, and boiler feed pumps) where thermal effects of cavitation become important, and 2) predicting unsteady, off-design operation of high energy systems. The generalized real fluid formulation in the CRUNCH CFD? tool is a unique capability that is critical for ?real? fluid systems. Furthermore, there currently are no tools to predict dynamic loads in high energy pump systems. The product developed here will provide a reliable, high-fidelity tool for modeling unsteady pump operation.