沉浸式换热器超声强化传热影响因素

Taking the immersed coil heat exchanger as the research object, the ultrasonic wave was imposed by means of vibration surface, and the influence of the ultrasonic amplitude and the inlet flow rate of the heat exchanger and the pressure outside the tube on the ultrasonic effect and the heat transfer enhancement were compared. The results showed that the increase of ultrasonic amplitude from 20μm to 35μm resulted in the increase of surface heat transfer coefficient from 15.67% to 26.71%, and the increase of external pressure from 0.1MPa to 1.0MPa led to the increase of surface heat transfer coefficient from 20.95% to 48.43%. When the inlet flow rate was reduced from 1.0m/s to 0.05m/s, the surface heat transfer coefficient increased from 1.76% to 39.01%. Increasing the ultrasonic amplitude, environmental pressure and reducing the medium flow rate could all enhance the acoustic streaming and acoustic cavitation effect and effectively improved the ultrasonic heat transfer enhancement effect; the high-pressure environment will cause the sound power to increase exponentially under the same amplitude and frequency ultrasonic vibration, and the high flow rate would reduce the sound energy density of the fluid medium. Both cases needed to match the appropriate ultrasound power to ensure the best effect of enhanced heat transfer.