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• A 3D-OHP with ammonia and liquid metal was first developed for high-power and high-heat-flux dissipation. • Liquid metal can promote the unidirectional flow in the OHP. • Liquid metal improves the heat absorption and release rate of the working fluid. • The 3D-OHP can effectively handle heat dissipation of 1000 W with local heat flux of 111 W/cm2. With the rapid development of microelectronics technology, the power of some advanced electronic devices has reached 1000 W with heat flux of 100 W/cm2. The problem of high-power and high-heat-flux thermal management has become the bottleneck of the development of advanced electronic devices. In this paper, a three-dimensional oscillating heat pipe (3D-OHP) with 18 channels was developed for this problem. A new hybrid fluid of ammonia and liquid metal was used as a working fluid. The wall temperature and heat transfer performance of the 3D-OHP charged with the hybrid fluid were investigated experimentally. The results indicate that the 3D-OHP can effectively solve the problem of heat dissipation with the heating power of 1000 W and the heat flux of 111.1 W/cm2. Liquid metal can ensure the efficient operation of ammonia OHP under supercritical pipe diameter, and promote the working fluid to form a unidirectional flow. Liquid metal has a great ability to absorb and release heat which significantly enhances the heat transfer performance of the 3D-OHP. When the heat flux reached 111 W/cm2, the 3D-OHP with 2.11% liquid metal had the best heat transfer performance, and the thermal resistance was 0.0351 °C/W. Compared with pure ammonia 3D-OHP, it could reduce the temperature difference of the 3D-OHP by 9.1 °C and enhance the heat transfer performance by 20.57%. The capacity of the ammonia-liquid metal 3D-OHP to deal with high-power and high-heat-flux is higher than the existing studies. [ABSTRACT FROM AUTHOR]

• Gallium-based liquid metal-copper foam TIM is prepared by galvanic corrosion. • The thermal conductivity of the TIM is 51.58±0.01 W/(m·K). • Under the pressure of 0.35 MPa, the TIM does not overflow. • With the increase in wettability, the thermal contact resistance decreased by 58.28%. As a promising thermal interface material (TIM), gallium-based liquid metal (GBLM) could significantly reduce the thermal contact resistance (TCR) at the solid-solid interfaces, while the leakage of GBLM and the wettability between liquid metal and solid surface restrict further application. In this study, the GBLM was wrapped with a copper foam (CF) skeleton, which prevents leakage and improves the thermal conductivity of the GBLM. Gallium-based liquid metal-copper foam (GBLM-CF) TIM was prepared by the self-wetting of the CF surface through the galvanic corrosion of GBLM. As the concentration of HCl increases from 0 to 5 M, the interfacial tension (IFT) in the HCl solution decreases from 536.80±1.00 mN/m to 481.52±0.49 mN/m, demonstrating that the IFT of the GBLM is inversely proportional to the concentration of HCl. Meanwhile, the decrease of contact angle (CA) by 8° indicates that the presence of CuGa 2 on the surface promotes the wettability of GBLM. With the increase of external pressure and the improvement of wettability, the TCR between the GBLM and the copper sheet decreased by 58.28%. The TCR of the sample using GBLM-CF as TIM is 83% lower than that of thermal grease. Moreover, the thermal conductivity of GBLM-CF TIM (51.58±0.01 W/(m·K)) is 212.6% higher than that of GBLM (16.50±0.02 W/(mK)). The GBLM-CF TIM presented in this study can be used for the efficient thermal management of electronic equipment. [ABSTRACT FROM AUTHOR]

• A liquid metal high temperature OHP (LMHOHP) was first developed. • The LMHOHP that can function at a temperature of over 500 °C. • The LMHOHP can transport heat of 3169 W and achieve a thermal resistance of 0.08 °C/W. This paper introduces the development of a liquid metal high-temperature oscillating heat pipe (LMHOHP) that can function under high-temperature conditions (over 500 °C). The LMHOHP has six turns with a total height of 310 mm. The sodium-potassium alloy (potassium 78%) was used as the working fluid, and the 310S stainless steel tube with an inner diameter of 6 mm as the shell tube. The LMHOHP heat transfer performance was investigated experimentally with a filling ratio of 45% at different input powers. Experimental results show that the LMHOHP can effectively generate steady-state oscillating motions at a working temperature of over 500 °C. When the steady-state oscillating motions exist, the temperature difference and thermal resistance between the evaporator and condenser were reduced significantly. At a heat input of 3169 W, the LMHOHP presents a minimum thermal resistance of 0.08 °C/W. This LMHOHP provides a new approach to next-generation high-temperature cooling devices. [ABSTRACT FROM AUTHOR]