Abstract
Pool boiling heat transfer measurements from heaters of varying aspect ratio were obtained in low-g (0.01 g ± 0.025 g) and high-g (1.7 g ± 0.5 g) using the KC-135 aircraft. The heater aspect ratio was varied by selectively powering 2×2, 2×4, 2×6, 2×8, and 2×10 arrays of heaters in a 10×10 heater array containing individual heaters 700×700 μm2 in size. Control circuitry was used to maintain a nominally isothermal boundary condition on the heater surface while the power dissipated by the heater was measured. Steady-state boiling data in low-g and high-g were obtained using FC-72 as the working fluid at two bulk fluid temperatures. At high wall superheats, boiling performance appears to decrease with an increase in aspect ratio. Strong thermocapillary convection was observed for a negligible gas concentration in the liquid. CHF was not observed for the heater used in this study indicating that CHF in low-g may be highly dependent on the surface characteristics of the heater in addition to the heater size.
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Henry, C.D., Kim, J. Thermocapillary effects on low-g Pool Boiling from microheater arrays of various aspect ratio. Microgravity sci. Technol. 16, 170–175 (2005). https://doi.org/10.1007/BF02945970
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DOI: https://doi.org/10.1007/BF02945970