Experimental Investigation On Heat Transfer Performance Of Pulsating Heat Pipe With Ternary Fluid

The development trend of electronic devices, gradually become miniaturized and integrated, which account for the over concentration of the high heat flux in a limited space. The adverse thermal environment can seriously degrade the operation stability of components. Therefore, effective heat dissipation is one of the key issues that affect the performance and service lives of electronic equipment. The pulsating heat pipe(PHP) is a kind of small, highly effective and more stable heat transfer device to solve the problem of high heat flux cooling. With the rapid increase of heat flux in the electronic devices, enhancing heat transfer performance of the PHP will always be one of the most important topics of the researches. The PHP is usually fabricated by capillary tube, belong to the micro-channel devices, the thermophysical properties of working fluid play an important role in heat transfer performance of the PHP. Heat transfer enhancement of the PHP with new working fluid has been studied extensively by more and more researchers.In this paper, a kind of ternary fluid was proposed, based on the study of enhancement on heat transfer performance of the PHP with nanofluid and self-rewetting fluid. It’s a mixture of two kinds of working fluid mentioned above, called self-rewetting nanofluid. The selection of nanofluid is the graphene oxide dispersion solution, self-rewetting fluid is the n-butanol aqueous solution. The heat transfer performance of the PHP with the ternary fluid was investigated. In contrast to de-ionized water, nanofluid and self-rewetting fluid, the ternary fluid can enhance the heat transport performance over the entire heat load range due to the comprehensive effects of high thermal conductivity and surface tension of inverse Marangoni effect. Through an analysis of the enhancement ratios, it is found that nanofluid can only enhance the performance of an OHP within a certain heat load range. The maximal enhancement ratio is about 11%. If the heat load increases, the heat transport performance of the OHP degrades. For a self-rewetting fluid, the maximum of enhancement ratio is only 6% as the heat load is low, as the heat load increases, the enhancement ratio decreases gradually. The PHP with ternary fluid shows excellent heat transport performance, the maximal enhancement ratio is approximately 15%. Therefore, the ternary fluid called self-rewetting nanofluid is considered to be appropriate working fluid for use in the PHP.The effect of the mass fraction of nanoparticle and n-butanol on the heat transfer performance of the OHP was investigated respectively. The experimental results show that there is an optimum constituent concentration of nanoparticle and n-butanol for the ternary fluid. The heat transfer performance of the PHP can reach high point at this optimum constituent concentration. The maximal enhancement ratio of self-rewetting nanofluid is about 16% corresponding to self-rewetting fluid and about 12% corresponding to nanofluid. A method was given based on the measurement of physical properties of the ternary fluid, which can determine an optimum constituent concentration corresponding to the best heat transfer performance of the PHP. The principle is that the self-rewetting nanofluid should have high thermal conductivity and a large surface tension gradient at the same time.