| In this study, the effect of random vibration on the capillary limit of commercial heat pipes for rugged electronics cooling has been investigated. The heat pipes included in the study utilize sintered powder, axial groove, wrapped screen and fiber bundle wick structures. The four heat pipes have been tested with the gravitational force both normal and parallel to the axis of the heat pipe, with and without vibration. The configuration with axial gravitational force included both orientations, that is the body force both complementing and opposing the capillary force produced by the wick. A bench-top shaker was used to provide vibration in the same plane as the gravitational force at a level of 0.1 g2/Hz across a frequency range of 20 to 2000 Hz (∼14g RMS). The capillary limit has been found to be sensitive to the wick structure, operating temperature (15°C to 75°C) and direction of gravity. These effects have been thoroughly documented in this thesis in the context of mathematical models used to predict heat pipe thermal performance. Negligible effects of vibration have been observed for all configurations tested. |
