Acceleration Effects on the Cooling Performance of a Partially Confined FC-72 Spray
| Autor: | Travis E. Michalak, Kirk L. Yerkes, Scott K. Thomas, John McQuillen |
|---|---|
| Rok vydání: | 2010 |
| Předmět: |
Fluid Flow and Transfer Processes
Materials science Critical heat flux Mechanical Engineering Aerospace Engineering Thermodynamics Heat transfer coefficient Condensed Matter Physics Coolant Volumetric flow rate Subcooling Heat flux Space and Planetary Science Heat transfer Water cooling Composite material |
| Zdroj: | Journal of Thermophysics and Heat Transfer. 24:463-479 |
| ISSN: | 1533-6808 0887-8722 |
| DOI: | 10.2514/1.46547 |
| Popis: | This paper discusses the effects of a variable-gravity environment on the performance of a subcooled partially confined spray. An experiment consisting of a test chamber, associated flow loops, and instrumentation was fabricated and flown on the NASA Reduced-Gravity Testing Platform. This modified KC-135 aircraft followed a parabolic flight path to provide various acceleration levels. The spray chamber contained a nozzle spraying onto an upward-facing thick-film resistor heater, which was mounted on an insulating glass pedestal. Thermocouples under the heater in the glass pedestal were used to determine the heater surface temperature. The glass pedestal was surrounded by an annular sump system, which was used to collect and remove the cooling fluid from the test chamber. The fluid used for this testing was FC-72, which is a nontoxic, nonflammable, and nonreactive refrigerant. Because of its dielectric nature, FC-72 was sprayed directly onto the thick-film heater. The parametric ranges of this experiment were as follows: heat flux to the spray was 21.1 ≤ q" sp ≤ 69.0 W/cm 2 , acceleration field was 0.15 ≤ a ≤ 1.80 g, coolant volumetric flow rate was 6.18 ≤ V ≤ 8.94 ml/s, and coolant subcooling was 23.1 ≤ Δ T sc ≤ 31.7 K. The heat fluxes tested were below the critical heat flux q" CHF . The wall superheat ΔT sat = T s - T sat was found to increase with heat input and acceleration and to decrease with subcooling and volumetric flow rate. |
| Databáze: | OpenAIRE |
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