Research on the audible acoustic field-enhanced heat transfer of double-pipe exchangers: Effect of laminar flow and turbulence, vertical and horizontal placement of pipes

Abstract

The acoustic field is considered an efficient and reliable technique for enhancing convective heat transfer. This study investigates the optimal experimental conditions of acoustic field-enhanced heat transfer using an experimental platform for convective heat transfer in a double-pipe exchanger. The experiment mainly explored the enhancement effect of the acoustic field on heat transfer by comparing laminar flow and turbulent flow states, as well as the arrangement of horizontal and vertical pipes. Meanwhile, acoustic wave frequency and inlet temperature of the thermal fluid were also considered as experimental variables. The results showed that compared to the horizontal pipe which has the best reinforcement efficiency at a frequency of 0.6 kHz, the vertical pipe in the laminar flow condition showed a high heat transfer capacity in the range of 0.6–0.8 kHz, with the best reinforcement efficiency reaching up to 43.6%. The significant heat transfer enhancement effect is mainly because 0.6 kHz is close to the acoustic resonance frequency, which further enhances the heat transfer effect. In the turbulent flow condition, the effect of the acoustic field on enhancing heat transfer is obvious when the pipe is arranged horizontally, and the reinforcement efficiency reaches a maximum of 24.5% at a frequency of 0.7 kHz.