Research Of Foucing And Stengthening Heat-transfer Of Spherical Ultrasonic Focusing System Based On Longitudinal-flexural Vibration Conversion

In the process of grinding, the traditional way of pouring cooling liquid cooling not onlyconsume large amounts of cooling fluid, in thermal efficiency is low, and the environmentalpollution, harm the operator health. Ultrasonic vibration assisted steam fog coolingtechnology atomization and infuse the cooling liquid to the surface of a heat source, reducedthe amount of coolant and greatly improving the cooling fluid of strengthening heat transferability, so as to realize the process of green and efficient cooling technology. In the researchon the basis of previous studies, put forward the new type of composite vibration bucklingmode focused ultrasound steam fog cooling system, this paper mainly discusses the theoryand experimental research of the new cooling system:Application of plate and shell vibration theory of elastic mechanics and helmholtzkirchhoff sound field theory analyzes the new focus on the system vibration characteristicsand sound field is focused on the characteristics, and is verified by experiment. Researchshows that: spherical shell bending vibration of radiation sound field has significant focusfeatures, focus position, the strength of sound pressure, the focal area shape under theinfluence of curvature radius of spherical shell; In certain cases structure, focusing on thecharacteristics affected by resonance frequency, focus on the effect of high order harmonicfrequency is better than low order harmonic frequency, but the focus sound pressure is lowerthan the lower order resonant frequency; Bending vibration and the radiation impedancematching gas medium is better than vertical vibration.It is proved that the new system has tworesonance patterns named as complete resonance and incomplete resonance. In the incompleteresonance patern, the system can work in the condition of either integral resonance or localresonance. The system design method is proposed for different working conditions based onthe research.Liquid is atomization in the bending vibration on the face of the disk in the newultrasonic vibration mist system. Through theoretical analysis and experimental vibrationcharacteristics of vibration atomization system, the radiation impedance and the acoustic fieldis studied. Results show that this system than the traditional longitudinal vibrationatomization system has higher power output ability, can make the liquid after atomization directivity and the role of more energy.It was proved that new system mainly works in themaster-slave resonance state and its resonance frequency is mostly depended on the structureof the transducer and the its output amplitude increase with the approaching of the resonancefrequency between the transducer and the flexural vibration disc.In the view of heat transfer ability of strengthening heat transfer by simulation analysisfor new focused ultrasound steam fog cooling system. Compared with the ordinary aerosolmist cooling, cooling ability of focused ultrasound aerosol mist cooling is more stronger. Indetermining the steam fog cooling medium conditions， by changing the amplitude andfrequency of focused ultrasound to study the steady state and transient heat transfer, get thedifference of the influence law of heat by exchange coefficient amplitude and frequency.Complex vibration mode of the new type of buckling transformation focused ultrasoundsteam fog cooling system of research results, the design and application of this system in thefuture have important practical significance.