Fabrication of cooling channels employing worm voids caused by friction stir based process: Considering cooling and fluid parameters

Abstract

The developments in compact high power mechanical and electrical devices naturally require heat removal systems that are equally small. Miniaturized heat exchangers (MHE) are manufactured either by joining multiple tubes or by connecting independent fluid channels fabricated in several steps. Friction stir channeling (FSC), is an innovative cost-effective technology that can be practically employed to reduce the fabrication process of connected channels into a single step. For this reason, the effects of manufacturing parameters of FSC on the main design factors of MHE should be clearly known. In the present study, novel tools are designed based on a comprehensive understating of complex material flow in friction stir based process (FSBP). These tools are proposed both to facilitate material separation and to enhance the amount of material removed from the channel holes. The FSC designed tools are experimentally employed in both laminar and turbulent flows to investigate the effects of tool geometry on the main performance parameters of cooling ducts. Flow resistance along with convection and conduction thermal resistances are introduced in this study to explore the produced channels. Evaluation of each tool by considering the geometrical, thermal, and flow parameters clearly indicates that the bi-directional threaded diamond-shape FSC tool is a viable tool that can pave the way for developing efficient thermal and flow designs in MHE systems.