Effect of Longitudinal Vibration on the Capillary Limit of a Wrapped Screen Wick Copper/Water Heat Pipe.
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH
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The effect of longitudinal vibration on the capillary limit of a copperwater heat pipe with a tightly wrapped screen wick was investigated. The capillary limit was measured over a range of operating temperatures under static conditions. A benchtop shaker was used to provide vibration in the longitudinal axis of the heat pipe. The capillary limit was measured at vibration frequencies of 10, 30, and 50 Hz. At each of these frequencies, tests were run at vibration amplitudes of 0.2 and 2.0 g. The pipe was maintained at a constant inclination angle and power throughput was increased until dryout occurred. The power throughput at dryout was considered the capillary limit. The measured capillary limit for each vibration test was compared to the static tests to determine the effect of the vibration. The results covered operating temperatures from 41.4 deg C to 96.6 deg C. A vibration amplitude of 0.2 g caused a 2.3 percent decrease in the capillary limit. However, there is a 3.7 percent uncertainty in the data. A vibration amplitude of 2.0 g at 30 and 50 Hz caused a 9.6 and 6.1 percent degrade in capillary heat transport limit, respectively. At 2.0 g and 10 Hz, there is a 1.8 percent decrease in capillary heat transport limit. Heat Pipes Vibration Vibration Testing Thermal Protection Working Fluids Heat Flux.
- Fluid Mechanics