Experimental Investigation On The Effects Of Nanoparticles On The Heat Transfer Performance Of The Sodium-potassium Alloy High-temperature Oscillating Heat Pipe

With the development of large-scale,intelligent,and lightweight ships,the volume of parts and components decreases and the heat flow density increases,which puts forward higher requirements for rapid heat dissipation.In the nuclear power supplies and nuclear power plants of nuclear-powered ships,there is a problem of quickly transferring heat from the core to the conversion system.In addition,many key high-temperature heat transfer issues are also involved in the fields of aerospace,solar energy utilization,and industrial temperature control.How to effectively conduct heat dissipation at high temperatures has become one of the key issues that restrict the further development of related fields.The emergence of oscillating heat pipe technology makes it possible to achieve efficient heat dissipation in a limited space.It is of great significance to investigate oscillating heat pipes that can be used in high-temperature environments and to enhance their heat transfer performance.Aiming at the problem of poor wettability of sodium-potassium alloy and high-temperature oscillating heat pipe wall surface,this paper starts with the surface modification of sodium-potassium alloy by nanoparticles and studies the influence of different nanoparticles on the wettability of sodium-potassium alloy and stainless steel substrate.On this basis,the heat transfer performance of sodium-potassium alloy high-temperature oscillating heat pipes added with diamond nanoparticles was tested,and the effect of nanoparticles on the heat transfer performance of high-temperature oscillating heat pipes was analyzed.Through the above research work,the following conclusions are drawn:（1）The massive diamond nanoparticles with a main particle size of 9.5nm～27nm have a better effect on improving the wettability of sodium-potassium alloy and stainless steel substrates,while the columnar Al₂O₃nanoparticles with an average particle size of 80nm have no obvious effect.（2）Compared with the high-temperature oscillating heat pipe without adding nanoparticles,the high-temperature oscillating heat pipe with diamond nanoparticles start-up more smoothly at low operating temperatures.（3）When the inclination angle was 0°,the start-up temperature of high-temperature oscillating heat pipes without/with adding nanoparticles was similar at low operating temperature,while the start-up temperature of oscillating heat pipes with nanoparticles added at other inclination angles was lower.After adding nanoparticles,the stable operating temperature of the oscillating heat pipes can be reduced.（4）As the inclination angle increases,the enhancing effect of diamond nanoparticles weakened,and the maximum strengthening effect rate was 15.46%when the inclination angle was 0°.（5）The higher the operating temperature,the greater the enhancement rate of nanoparticles on the heat transfer capacity of the enhancing heat pipe.