Characterization of capillary pumping amount in novel sintered zeolites and hybrid zeolite-Cu for heat pipe applications

In this study, a novel sintered zeolite and hybrid zeolite-Cu were developed as wick for heat pipe application. Important properties of the sintered zeolite and hybrid zeolite-Cu, such as wick microstructure, capillary pumping performance, and wettability were considered and evaluated. The wick was prepared by a sintering method. The granule sizes of the zeolite and Cu were 100 and 200 µm, respectively. The working fluid used for testing the capillary pumping amount and the contact angles (CAs) was distilled water. The capillary pumping amount was tested by electronic balance, recorded by a computer, and compared with that of biomaterial wick. The CAs were measured by capturing and measuring liquid droplet images on the flat surface of the wick. The results show that the highest capillary pumping amount was achieved by the 100-µm-grain hybrid zeolite-Cu with 25/75% zeolite-Cu composition. The smallest CA was obtained with the 200-µm-grain pure zeolite. The decrease in the CA of the hybrid zeolite-Cu increased its wettability and capillary pumping performance. This study also showed that the CA could affect wettability and capillary pumping amount of wick candidates.