Study On Application Of Ultrasonic Cavitation And Nano-fluid In Enhanced Heat Exchange

Research on heat transfer has always been the focus of industrial research.Almost all industrial production activities are inseparable from the transfer of heat.The transfer efficiency of heat energy is directly related to the energy consumption level of enterprises.In order to improve heat transfer efficiency,many experts and scholars in related fields have conducted long-term experiments and explorations,and obtained a series of research results,which also promoted the development of new enhanced heat transfer forms and heat transfer materials.In addition,fine heat exchange components and high heat flux requirements present challenges to conventional heat transfer forms.Nanofluids and ultrasonic cavitation technology have been proven to have an important strengthening effect on heat transfer under certain conditions,and have received extensive attention in recent years.However,nanofluids and ultrasonic cavitation technology can hinder heat transfer under certain conditions.Therefore,research on the basic and application direction of this technology is extremely urgent.In this paper,the effects of ultrasonic cavitation and nano-solutions are explored experimentally.The relationship between liquid level and cavitation phenomenon is studied by noise measurement method.The difference between liquid level acoustic signal acquisition and hydrophone acoustic signal acquisition is compared.Using this signal feature,ultrasonic cavitation is analyzed based on acoustic wave superposition process.The phenomenon of changes with liquid level and ultrasonic power reveals the existence of standing wave field in the ultrasonic field from experimental phenomena and theoretical analysis,filling the gap in the basic research of ultrasonic cavitation in this field;using cavitation noise sensor for cavitation noise The signal is collected outside the liquid,and the relationship between the standing wave field and the cavitation phenomenon is explored.The existence of the preferred value of the cavitation liquid depth is revealed,and the theoretical analysis is carried out according to the experimental results,which lays out or consolidates the ultrasonic cleaning,ultrasonic descaling,etc.The theoretical basis of ultrasonic application;the influence of liquid level on ultrasonic cavitation intensity is studied.It is found that there may be a critical liquid level between thick liquid cavitation and thin liquid cavitation,which provides direction and basis for further research in this field.The distribution law of ultrasonic cavitation field was explored by metal film etching method.The intrinsic relationship between ultrasonic cavitation field distribution and cavitation shielding phenomenon was revealed.The general method of obtaining stable nano-solution was combed,and the dispersing agent combined with ultrasonic was proposed.The cavitation configuration method and its stability mechanism are explained in detail.The influence of nanoparticles on the ultrasonic cavitation field is further analyzed.A new method to improve the cavitation field distribution is proposed.The application of acoustic cavitation technology in practical large projects is proposed.Provide new ideas.The heat transfer experiments of single-field,single-nanofluid and ultrasonic cavitation combined with nanofluids were carried out by using the platinum wire hot-wire method.The acoustic flow and acoustic cavitation of the ultrasonic field have strong perturbation ability,which enhances the heat transfer process.When the base liquid temperature is 40℃,the strengthening efficiency is the highest,and the strengthening efficiency is 8.62%.Four different concentrations of nanofluids are used to conduct heat transfer experiments at the same base liquid temperature.The nanofluid with the volume fraction of 0.01%has the most heat transfer effect.Well,when the fluid temperature is 40℃,the nanoparticles are most active;the effect of ultrasonic cavitation on the heat transfer of nanofluids is studied.The experimental results show that under the action of the ultrasonic sound field,the boiling curve shifts to the left overall,but the critical heat flux decreases.This experiment provides data support for the conclusion that the heat transfer effect of sound field and nano solution is universal,and develops a variety of methods to improve heat transfer effect.According to the heat transfer effect,the mechanism of action of ultrasonic field on nanoparticles is analyzed.