The Effect of Variable Gravity on the Cooling Performance of a 16-Nozzle Spray Array
Interim rept. 30 Nov 2006-14 Sep 2007
AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH PROPULSION DIRECTORATE
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The objective of this thesis was to investigate the cooling performance of a 16-nozzle spray array, using FC-72 as the working fluid, in variable gravity conditions with additional emphasis on fluid management and flow stability. A flight test experiment was modified to accommodate a 16-nozzle spray array, which was then tested in the parabolic flight trajectory environment of NASAs C-9 reduced gravity aircraft. The 16-nozzle array was designed to cool a 25.4 by 25.4 mm area on a thick film resistive heater used to simulate electronic components. Data was taken and reduced as a result of flight tests conducted over the course of two flight weeks each week consisting of four flights, each flight consisting of 40 to 60 parabolas. The flight tests were conducted in order to examine gravity effects on spray cooling performance and to evaluate a novel liquid-vapor separator design. The mass flow rate through the 16-nozzle spray array ranged from 13.1 m 21.3 gs for the spray cooling analysis and 14m 35 gs for the separator evaluation. The heat flux at the thick film resistor ranged from 2.9 q25 Wcm2, the subcooling of the working fluid.
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