Evaluation of capillary wetting performance of micro-nano hybrid structures for open microgrooves heat sink

摘要

Thermal management for various applications have promoted the development and in-depth investigations of open capillary microgrooves. Micro-nano hybrid grooves heat sink (combined of microgrooves and Ti nanocoatings) is proposed in this study. The wicking performance, which in terms of capillary wetting length, capillary wetting uniformity and capillary performance parameter determines the design and thermal management of the microgrooves heat sink. In this study, wicking performance from micro-nano hybrid grooves heat sink has been studied experimentally, with theoretical analysis. The wicking performance of the smooth and fully coated with Ti nano-coatings on borosilicate glass surfaces (3 different thicknesses), with 3 different grooves dimensions, has been studied in detail. A quantitative and automatic optical method using IR imaging is applied in this study to identify the capillary wetting length (dryout point) through the whole width of the microgrooves, even in each groove, based on the pixel differences of an IR image. Results show that the Ti nano-structured surfaces significantly improve the capillary wetting performance, compared with bare surfaces.