Effect of transverse vibration on the capillary limit of a wrapped screen wick copper/water heat pipe

Abstract

Abstract : The effect of transverse vibration on the capillary limit of a copper/water 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 bench-top shaker was used to provide vibration normal to the longitudinal axis of the pipe, and the capillary limit was measured at vibration frequencies of 30, 250, and 1000 Hz. At each of these frequencies, tests were run at vibration levels of 1.0, 2.5, and 5.0 G. The pipe was maintained at a zero degree inclination angle and power throughput was increased until dryout was achieved. The power throughput at dryout was considered to be the capillary limit under the conditions imposed for that test. The measured capillary limit from each vibration test was compared to those from the static tests. The results spanned pipe operating temperatures from 500 C to 75 deg C. For the frequencies and amplitudes tested, there was found to be little or no effect on the capillary limit due to vibration normal to the longitudinal axis. It is recommended that further study in this area be concentrated on vibration parallel to the longitudinal axis.... Heat pipes, Vibration, Vibration testing, Thermal protection, Working fluids, Conductive heat transfer, Heat flux.