Visualization Experimental Study on Silicon-Based Ultra-Thin Loop Heat Pipe Using Deionized Water as Working Fluid

Abstract

As a type of micro flat loop heat pipe, s-UTLHP (silicon-based ultra-thin loop heat pipe) is of great significance in the field of micro-scale heat dissipation. To prove the feasibility of s-UTLHP with high heat flux in a narrow space, it is necessary to study its heat transfer mechanism visually. In this paper, a structural design of s-UTLHP was proposed, and then, to realize the working fluid charging and visual experiment, an experimental system including a holding module, heating module, cooling module, data acquisition module, and vacuum chamber was proposed. Deionized water was selected as a working fluid in the experiment. The overall and micro phenomena of s-UTLHP during startup, as well as the evaporation and condensation phenomena of s-UTLHP during stable operation, were observed and analyzed. Finally, the failure phenomenon of s-UTLHP was analyzed, and several solutions were proposed. The observed phenomena and experimental conclusions can provide references for further related experimental research.

An Experimental Study of a Composite Wick Structure for Ultra-Thin Flattened Heat Pipes

“…This results in elevated temperatures within these devices, which in turn constrains their further development [ 1 , 2 , 3 ]. Ultra-thin flattened heat pipes (UTHPs) exhibit a number of advantages, including small size, lightweight, quick startup performance, good temperature uniformity, and customizable shape [ 4 , 5 ]. Therefore, the rational use of high-performance UTHPs can effectively solve the cooling issue in these devices, reduce the operating temperature, and enhance reliability and safety [ 6 , 7 ].…”

Assessment of Vapor Formation Rate and Phase Shift between Pressure Gradient and Liquid Velocity in Flat Mini Heat Pipes as a Function of Internal Structure

“…To avoid this, one of the cooling methods uses thermal tubes. A great diversity of thermal tubes has appeared, as shown by [2,[4][5][6], who mentions the use of FMHPs in electronics cooling, space thermal control, aircraft devices, traction drives, audio amplifiers, in cooling of closed cabinets in harsh environmental conditions, space applications under vacuum conditions [4,7] nanofluidic technologies in medicine, process engineering, avionics applications, solar photovoltaic/loop-heat-pipe, (PV/LHP) heat pump system [8] electronic applications, solar units, and aircraft [9] self-driving car, smart TV, smart grid, aerospace, radar, camera, computer, cellphone [10], solar energy systems, heat recovery systems, air conditioning systems, cooling of energy storage and electronic equipment, industrial applications and space apparatus.…”

Editorial for the Special Issue on Heat and Mass Transfer in Micro/Nanosystems

“…Optimal operation conditions have also been proposed to eliminate the satellite droplets for deionized water. In the article by Song et al [ 2 ], the authors developed a structural design to visualize the evaporation and condensation processes in the silicon-based ultra-thin loop heat pipe (s-UTLHP), and performed experimental measurements to study the heat transfer mechanism in such devices. To gain a more accurate thermal measurement for microfluidic devices, Meng et al [ 3 ] proposed the use of a liquid metal to fill the gap space between the temperature sensor and the microfluidic substrate, and they also tested this concept on a microchennel chip with gallium.…”