Influence of ultrasonic treatment on heat transfer in the heat exchanger

Abstract

This paper deals with the influence of guided ultrasonic waves on heat transfer. Two piezoelectric transducers, whose structure can be vibrated at different powers and at their resonant frequency in the ultrasonic range of 27–45 kHz, were placed on the plates of a heat exchanger to inhibit the formation of a mineral deposit. These waves were set to diffuse only into the metal plates of the exchanger. During these tests, an increase in the heat transfer between the two fluids was directly observed on the continuous recording of the outlet temperature, on the calculations of the global exchange coefficient, and on the flow exchanged between the two fluids in the laminar regime. Tests are presented in this article, tests in the presence of the 45 kHz transducer, another with a 27 kHz transducer, and which combines the two have a different positioning on the exchanger. The results obtained from the ultrasonic guided waves are similar to the classical ultrasonic waves.