Variable-Gravity Effects on a Single-Phase Partially-Confined Spray Cooling System

Abstract

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Electromagnetic Control of High Heat-Flux Spray Impingement Boiling Under Microgravity Conditions

“…Yerkes et al (2006) have measured the spray droplet Sauter mean diameter and velocity for this nozzle type to be 48 grm and 12 m/s, respectively, at a flow rate of 9.5 x 10-6 m 3 /s. Nozzle-heater spacing for the majority of the present results is 13 mm, and heater diameter is 16 mm.…”

“…The initial baseline data without electric field effects by Hunnell (2005) has been nondimensionalized using a slightly different non-dimensional heat flux, called (GA)init herein; this was the initial definition used by Yerkes et al (2005). In this definition, the temperature difference in Equation (4.1) was replaced by T.,,,wi.…”

“…Kato et al (1994) also used orientation to simulate jig conditions, although they used a horizontal spray to simulate conditions of jig, and found data that was comparable to that of Yoshida et al A group at the Air Force Research Laboratory, Propulsion Directorate, Power Division (AFRL/PRPS) under the direction of Dr. Kirk L. Yerkes has been investigating the ability of spray impingement boiling to achieve higher heat transfer performance in a space and weight efficient manner under conditions of variable gravity. Baysinger et al (2004) and Yerkes et al (2006) describe the AFRL experiment, which has been flown several times on NASA variable gravity research aircraft. From its inception, the present (WVU) investigation of electrical body forces in spray impingement boiling has been closely coordinated with AFRL so as to complement and extend the non-electrical AFRL research.…”

“…T, is the heater surface temperature, computed from the measured interface temperature at the bottom of the heater substrate. The heat transfer model developed by Yerkes et al (2006) for the ITO heater has been extended in an approximate way to include the effect of the insulating glass layer on the top side of the TFR ceramic heater in the calculation of the heater surface temperature, T, (Hunnell et al, 2006). A simple one-dimensional conduction heat transfer thermal resistance across the insulating glass layer on the side of the TRF heater in contact with the working fluid has been used to estimate a temperature drop across this glass layer in order to get an estimate of T,.…”

“…The thermocouple labeled as "TI, is installed immediately beneath the heater, approximately 0.5 mm from the heater surface that is contacted by the spray. The analysis developed by Yerkes et al (2006) has been used to compute the heater surface temperature from the measured temperature 0.5 mm below the heater surface in contact with the working fluid.…”