Heat transfer enhancement by acoustic streaming in a closed cylindrical enclosure filled with water

Abstract

Heat transfer enhancement in presence of acoustic streaming in a closed cylindrical enclosure filled with water on a down-ward-facing horizontal heating surface was measured experimentally. Acoustic streaming is induced by the vibration of the lower plate by means of an ultrasonic Bolted Langevin transducer. Standing wave was generated between a large heating source as a reflector and the vibrating plate. The upper plate was heated with a constant heat flux and side-walls were kept at the constant temperature. Therefore, the gravitational effects on the flow fields were negligible in this study and the heat transfer enhancement was due to vibrations. The effects of the transducer power, the height of the heater above the vibrating plate and the heat flux of the heater were considered separately in these measurements. The results show that the enhancement of the heat transfer between the heat source and the bulk water near the vibrating plate can be up to 390% with the acoustic streaming generated by the ultrasonic vibrations. The increase in the transducer power and the decrease in the height of the heater cause the higher heat transfer coefficient in the enclosure.