NASA SBIR 2002 Solicitation


PROPOSAL NUMBER:02-II A4.01-8734 (For NASA Use Only - Chron: 023265 )
SUBTOPIC TITLE: Space Transportation Architecture Definition
PROPOSAL TITLE: Dynamic Transfer Function Measurements for Cavitating Pumps

SMALL BUSINESS CONCERN: (Firm Name, Mail Address, City/State/ZIP, Phone)
Concepts ETI, Inc.
217 Billings Farm Road
White River Jct , VT   05001 - 9486
(802 ) 296 - 2321

PRINCIPAL INVESTIGATOR/PROJECT MANAGER: (Name, E-mail, Mail Address, City/State/ZIP, Phone)
Dr. Karl D. Wygant
217 Billings Farm Road
White River Jct , VT   05001 - 9486
(802 ) 296 - 2321

The Phase I effort demonstrated the feasibility of measuring cavitating inducer dynamic transfer functions using an upgraded Concepts NREC pump test facility. As there are no analytical tools or experimental facilities in the world today that can quantify a cavitating inducer?s dynamic transfer function, developing this capability is crucial for the safety, reliability and competitiveness of the American Space Industry. An innovative experimental technique that uses mappings of inlet and exit flow and pressure fluctuations to quantify a cavitating inducer?s dynamic transfer function is proposed. A cavitating inducer can be a source of instability in a rocket vehicle. Due to cavitation dynamics, inlet flow perturbations maybe amplified by the inducer resulting in very large flow and pressure fluctuations in the fuel system. The resulting dynamic couplings can lead to vehicle instability (POGO) as well as generate intense dynamic loadings on the turbopump. The feasibility of implementing the proposed measurement technique on an upgraded Concepts NREC water flow test loop was demonstrated in the Phase I effort. Implementation of the test loop upgrades and demonstration of the transfer function measurement technique on a scaled inducer with a historical pedigree will occur in the proposed Phase II effort.

As mission requirements lead to higher power density turbopumps with lower specific weights and higher suction specific speed requirements the potential for flow-induced dynamic instabilities, both at the turbopump level and at the system level, increase. Rocket vehicle dynamic models require an accurate dynamic characterization for the inducer. The proposed experimentally measured dynamic transfer functions will provide accurate and reliable pump dynamic attributes which are necessary to assess the probability of destructive flow instabilities, such as cavitation surge and rotating cavitation, and their effect on engine component reliability and life expectancy and integrated vehicle system instability.

High energy density turbomachines such as gas re-injection pumps and compressors and high-energy density industrial pumps are a source of instability. Accurate dynamic characterizations of these machines are required to ensure safe and reliable operation of the systems into which they are installed. In addition to understanding the dynamic attributes of these machines under cavitation or stalled conditions, the dynamic transfer function under normal operating conditions is also required. The methodology proposed to measure the dynamic transfer function of a cavitating inducer is transferable. The proposer is well positioned to commercialize the technology to both aerospace and industrial customers.

Form Printed on 10-03-03 11:34