Experimental Study On The Effect Of Nanoparticles On The Heat Transfer Performance Of The Oscillating Heat Pipe

The report to the Eighteenth National Congress of the Communist Party of China referred to the China’s strategy of building an ocean power, which adds to the possibility of more electronic components being used on large modern ships. As the rise of electronic components’operating temperature will affect their reliability, the cooling of these electronic components has become a very important issue.In recent years, the OHP in particular the nanofluids OHP has been known as an effective mean to solve the cooling problem of narrow space with high heat flux. The addition of nanoparticles in OHP has also become a hot topic worldwide. Due to the flow and heat transfer process of the combination of fluid, solid and gas, the rule and mechanism are highly complicated.In this paper, both experiments and mechanism study have been conducted to investigate the effect of SiO2 nanoparticles on the heat transfer performance of OHP. In the aspect of experiments, the effect of heating load, inclination angle, nanoparticle mass concentration and nanofluids suspension characteristic is studied. In the aspect of mechanism, the change of surface condition is studied. The experimental results showed that:(1) The heat transfer performance was enhanced with the increase in heating load.(2) The OHP has a strong dependence on inclination angle. There is an inclination angle between 30° and 90° which leads to the best start-up performance of OHP.(3) Because of the suspension characteristics of nanofluids OHP, the initial heat transfer performance was poor after the OHP was put aside for a long period and the heat transfer performance was return to the level that the OHP was put aside after being run for a period.(4) The phenomena that SiO2 nanoparticle enhanced heat transfer performance of OHP are mainly due to the change on the surface condition within evaporating section. The effect of nanoparticles made the contact angle decreased from 78.8° to 14.1° after the experiments and wetting performance were enhanced, thus increasing the evaporation of the evaporator.(5) When the inclination angle was 0°, the addition of SiO2 nanoparticles added to the deterioration of heat transfer performance of OHP. This is mainly because the high viscosity of nanofluids (When the temperature is 50 ℃, the viscosity of 0.6wt%SiO2 nanofluids is 16.63% larger than that of water) added to the resistance of working fluid flowing from condensing section to evaporating section and prevented the heat transfer of OHP.