Effect of surface roughness on pool boiling heat transfer in an ultrasonic field

An experiment was carried out to investigate the effect of ultrasonic field on the heat transfer of the sub-cooled pool boiling. A horizontal heated plate with varying surface roughness was put in water pool under sub-cooled conditions at atmospheric pressure. The experimental results indicate that the ultrasonic field assists to enhance the heat transfer at the nature convection and initial boiling conditions. Moreover, the wall temperature overshooting on the polished surface is effectively eliminated. However, the ultrasonic vibration exerts slight influences on the boiling heat transfer at high heat flux, and it is found that the heat transfer is even inhibited on the smooth surfaces under certain ultrasonic intensity.