Potential cavitating venturi modifications to improve performance at low inlet subcooling: Backward facing steps and threaded throats
- NASA Johnson Space Center, Houston, TX (United States). Crew and Thermal Systems Division
- McDonnell Douglas Aerospace, Houston, TX (United States). Thermal Control Systems Dept.
Cavitating venturis (CVs) were to be used to passively control the flow of liquid ammonia to the evaporators in the Space Station Freedom (SSF) two-phase active thermal control system (ATCS). Because the SSF ATCS CVs would have operated at a low value of inlet subcooling (on the order of 100 kPa or 15 psid) to conserve electrical power, an overflow phenomenon could have occurred. During overflow the mass flow rate is higher than the choked limit. Once overflow occurs, cavitation is reestablished only when the downstream pressure is decreased to a low value. To reduce or eliminate the occurrence of CV overflow in the SSF ATCS, several design solutions were developed, manufactured, and tested. Cavitating venturis with a backwards facing step immediately downstream of the throat were tested, as was a cavitating venturi with a threaded throat. Overflow recovery data were obtained for modified cavitating venturis and for unmodified CVs with identical throat sizes and geometry. In the present work, the rationale behind the CV modifications is outlined and the final designs are described. The test apparatus and test approach are summarized, and the experiment results are discussed for both the modified and unmodified CVs. The net effects of the modifications are reviewed, and recommendations are made for use of cavitating venturis at low inlet subcooling.
- OSTI ID:
- 100935
- Report Number(s):
- CONF-940659-; ISBN 0-7918-1373-8; TRN: IM9540%%409
- Resource Relation:
- Conference: 1994 American Society of Mechanical Engineers (ASME) Fluids Engineering Division summer meeting, Lake Tahoe, NV (United States), 19-23 Jun 1994; Other Information: PBD: 1994; Related Information: Is Part Of Cavitation and gas-liquid flow in fluid machinery and devices. FED-Volume 190; O`Hern, T.J.; Kim, J.H.; Morgan, W.B.; Furuya, O. [eds.]; PB: 350 p.
- Country of Publication:
- United States
- Language:
- English
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