Experimental investigation of bendable heat pipes using sintered copper felt wick

The feasibility of using sintered copper felt wicks for developing bendable heat pipes was demonstrated by fabricating two copper-water heat pipes. This work highlights a study of the effect bending has on the performance of these heat pipes from their nominal straight geometry. Flexible and pre-bent heat pipes have been studied and successfully demonstrated in the past. Bendable heat pipes, which are fabricated as straight heat pipes, which can be bent as needed for the application, are a unique class of heat pipes developed during this study. The effect of bending on temperature drop, performance and performance limits was investigated and is reported here. The heat pipes used for testing were made using oxygen free copper for the container and water as the working fluid. The wick was made from sintered copper felt and provided the post fabrication bendability feature of these heat pipes. It was found that the performance of the heat pipe in terms of copper equivalence decreased with increasing bending angles. However it was noted that the heat transfer capacity was not adversely affected.