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Variable Gravity Effects on the Cooling Performance of a Single Phase Confined SprayThe objective of this paper is to discuss the testing of a spray cooling experiment designed to be flown on NASA's KC-135 Reduced Gravity Testing Platform. Spray cooling is an example of a thermal management technique that may be utilized in high flux heat acquisition and high thermal energy transport concepts. Many researchers have investigated the utility of spray cooling for the thermal management of devices generating high heat fluxes. However, there has been little research addressing the physics and ultimate performance of spray cooling in a variable gravity environment. An experimental package, consisting of a spray chamber coupled to a fluid delivery loop system, was fabricated for variable gravity flight tests. The spray chamber contains two opposing nozzles spraying on target Indium Tin Oxide (ITO) heaters. These heaters are mounted on glass pedestals, which are part of a sump system to remove unconstrained liquid from the test chamber. Liquid is collected in the sumps and returned to the fluid delivery loop. Thermocouples mounted in and around the pedestals are used to determine both the heat loss through the underside of the IT0 heater and the heat extracted by the spray. A series of flight tests were carried out aboard the KC-135, utilizing the ability of the aircraft to produce various gravity conditions. During the flight tests, for a fixed flow rate, heat input was varied at 20, 30, 50, and 80W with variable gravities of 0.01, 0.16, 0.36, and 1.8g. Flight test data was compared to terrestrial baseline data in addition to analytical and numerical solutions to evaluate the heat transfer in the heater and support structure . There were significant differences observed in the spray cooling performance as a result of variable gravity conditions and heat inputs. In general, the Nussult number at the heater surface was found to increase with decreasing gravity conditions for heat loads greater than 30W.
Document ID
20050203675
Acquisition Source
Headquarters
Document Type
Conference Paper
Authors
Michalak, Travis
(Air Force Research Lab. United States)
Yerkes, Kirk
(Air Force Research Lab. United States)
Baysinger, Karri
(Air Force Research Lab. United States)
McQuillen, John
(NASA Glenn Research Center Cleveland, OH, United States)
Date Acquired
August 23, 2013
Publication Date
January 1, 2005
Subject Category
Fluid Mechanics And Thermodynamics
Meeting Information
Meeting: ASME Heat Transfer Conference
Location: San Francisco, CA
Country: United States
Start Date: July 17, 2005
End Date: July 22, 2005
Funding Number(s)
CONTRACT_GRANT: SAA3-307
OTHER: 22R-101-53-03-61-01
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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