NASA SBIR 2003 Solicitation


PROPOSAL NUMBER: 03- II A4.06-9873
SUBTOPIC TITLE: Launch Vehicle Subsystems Technology
PROPOSAL TITLE: Modeling Unsteady Cavitation Effects and Dynamic Loads in Cryogenic Systems

PRINCIPAL INVESTIGATOR/PROJECT MANAGER (Name, E-mail, Mail Address, City/State/Zip, Phone)
Ashvin Hosangadi
6210 Keller's Church Road
Pipersville, PA 18947-1020
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 turbopumps. Cavitation effects, particularly at low-flow, off-design conditions, generate large amplitude pressure fluctuations that result in performance loss, and may interact with other components to generate damaging system-wide instabilities. The innovation proposed here is the development of a numerical tool that can predict amplitudes and frequencies of dynamic pressure loads in cryogenic turbopumps. This innovation will address the inclusion of advanced unsteady cavitation models for cryogenic fluids, development of boundary conditions that include interactions with other system components, and unsteady turbulence models for off-design conditions. The resulting product, a specialized version of the multi-element unstructured CRUNCH CFDREG code, will be a well-validated and reliable analysis tool that can be used to predict off-design performance of liquid rocket turbopumps. Furthermore, this tool can provide unsteady loading information necessary for stress and fatigue life modeling of inducer blades. It would also be able to quantify an inducer's mean head breakdown characteristics as a function of design variables. Thus this simulation software will be used for providing design support, as well as being an analysis tool for diagnosing cavitation related anomalies in operational systems.

The commercial applications for our product are broad and include critical high-energy pumps for power generation and the petrochemical market, as well as the marine propeller arena. Many of these commercial systems are designed for long-life operation (on the order of 5 years for boiler feed pumps, for example) and reduced system life due to cavitation damage can lead to severe financial loss and loss of market share. The ability to model the dynamics associated with transient start-ups as well as off-design operation would provide significant advantage to commercial companies by improving designs and reducing testing and repair costs.

Our product addresses a core need of NASA in its strive to design safer and more versatile liquid rocket engines for upcoming programs such as Project Constellation for a new Crew Exploration Vehicle, as well as the Mission to the Moon. These systems will use liquid hydrogen and oxygen, and the ability to accurately model the turbopump performance over a wide range of off-design conditions will help reduce product development and testing costs. This tool will also enable simulations of instabilities in high-pressure, cryogenic test stands and support the design of more robust flow devices such as valves and venturis.