Chao Chang,Yaoguang Yang,Lilin Pei,Zhaoyang Han,Xiu Xiao,Yulong Ji
With the rapid development of electronic technologies towards high integration, high power and miniaturization, thermal management has become an increasingly important issue to guarantee the reliability and service life of electronic devices. The oscillating heat pipe (OHP), which was governed by thermally excited oscillating motion, was considered as a promising technology to dissipate high-density heat and had excellent application prospects in many important industrial processes. A flat-plate OHP, however, was fabricated by traditional welding methods, which were difficult and inefficient, resulting in increasing the cost and wasting the production time. In this work, we adopted a new metal 3D printing technology to develop an aluminum flat-plate OHP, which made it facile to build complex inner channels with high-precision molding at one time. AlSi10Mg powders, as raw materials, were selectively melted and solidified to form the container of the flat-plate OHP. The sintered inner surface presented excellent wettability to the working fluid, which facilitated the evaporation of the working fluid. Acetone was chosen as the working fluid, and the filling ratios with a range of 40–70% were loaded into the flat-plate oscillating heat pipe to analyze its effect on heat transfer performance. It was found that the 3D-printed flat-plate OHP with a 60% filling ratio had a better heat transfer performance and a lower thermal resistance, and it was able to work properly in both vertical and horizontal operation modes. The 3D-printed flat-plate OHP had been successfully applied for the thermal management of high-power LEDs, and the results showed that the temperature of LEDs was maintained within 60 °C, and its service life was prolonged.Keywords:3D printing;oscillating heat pipe;thermal resistance;heat transfer performance
As flexible electronic technologies rapidly developed with a requirement for multifunction, miniaturization, and high power density, effective thermal management has become an increasingly important issue. The oscillating heat pipe, as a promising technology, was used to dissipate high heat fluxes and had a wide range of applications. In this paper, we reported the fabrication and heat transfer performance evaluation of a polymer-based flexible oscillating heat pipe (FOHP) prepared using 3D printing technology. The 3D-printed inner surface presented excellent wettability to the working fluid, which was beneficial for the evaporation of the working fluid. Ethanol was selected as the working fluid, and the influence of the filling ratios range of 30–60% on heat transfer performance was analyzed. It was found that a 3D-printed FOHP with a filling ratio of 40% presented the best heat transfer performance with the lowest thermal resistance, and the fabricated heat pipes could be easily bent from 0° to 90°. With the best filling ratio, the thermal resistance of the FOHPs increased with larger bending angles. In addition, the 3D-printed FOHP was successfully applied for the thermal management of flexible printed circuits, and the results showed that the temperature of flexible printed circuits was kept within 72 °C, and its service life was guaranteed.Keywords:3D printing;flexible oscillating heat pipe;thermal resistance;thermal performance
Chao Chang,Xiaoyu He,Zhaoyang Han,Lilin Pei,Zongyu Wang,Yulong Ji
Developing energy harvesting and conversion technology is of great significance to mitigate the energy crisis and realize the sustainable development of human society. In this work, we designed and fabricated a thermal energy harvesting and conversion device by integrating a tube-based triboelectric nanogenerator (TENG) into a copper oscillating heat pipe (OHP). The tube-based TENG was composed of two copper electrodes uniformly distributed along a polytetrafluoroethylene (PTFE) tube. The copper OHP with an inner diameter of 2 mm had 6 turns and deionized water (DI) was chosen as the working fluid. When thermal energy was added to the OHP, liquid plugs in the OHP were thermally excited and flowed into the PTFE tube, resulting in the generation of an alternating flow of electrons between the two electrodes. This TENG-OHP system successfully generated more than 7.0 V of open-circuit voltage and more than 0.32 μW of output power. The generated electrical energy can be used to power many small electronics, such as capacitors and light-emitting diodes (LEDs). Therefore, these findings will offer an alternative approach to harvest and convert thermal energy heat in many devices or systems that involve the heat generation and heat transfer process.
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