Cavitating venturi performance at low inlet subcooling: Normal operation, overflow and recovery of overflow
- 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 have been 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 head rise of the SSF ATCS pump was low to conserve electrical power, the inlet subcooling at the cavitating venturi would have been lower than is the case in normal CV applications. Testing at NASA/Johnson Space Center has shown that when cavitating venturis are operated at low values of inlet subcooling (on the order of 100 kPa or 15 psid), an overflow phenomenon can occur. Here the flow is liquid throughout the venturi and flows at a higher mass flow rate than the cavitation limit. Once overflow occurs, cavitation is reestablished only when the downstream pressure is decreased to a low value. Overflow test data were obtained for six cavitating venturis with throat diameters between 0.28 and 1.83 mm (0.011 and 0.072 in). Analysis of the test result showed that overflow could not be sustained beyond a critical value of the superheat pressure at the cavitating venturi throat. In the present work, the phenomenon of overflow is explored and its implications for cavitating venturis in general applications and for applications similar to SSF are discussed. Recommendations are made for predicting the mode of operation of a cavitating venturi at low values of the inlet subcooling.
- OSTI ID:
- 100934
- Report Number(s):
- CONF-940659-; ISBN 0-7918-1373-8; TRN: IM9540%%408
- 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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