Synergistic heat transfer enhancement and drag reduction in spiral wound tubes via ultrasonic excitation

This study innovatively couples ultrasonic active control technology with the structural characteristics of spiral-wound tube heat exchangers, proposing a novel multi-physical field synergistic approach for heat transfer enhancement. A tube bundle-acoustic field interaction experimental system was established to study the effects of the intensity (133,333 W/m 2 , 233,333 W/m 2 , 333,333 W/m 2 ) and frequency (21 kHz, 25 kHz, 28 kHz) of ultrasonic waves, the installation position of transducers (inlet-only, outlet-only, simultaneous inlet-outlet), as well as the influence of installing different numbers of transducers (1–4) under different working conditions on the comprehensive heat exchange drag reduction capacity of the tube bundle were studied. The results demonstrate that ultrasonic technology provides dual enhancements: heat transfer intensification and drag reduction. The experimental results demonstrate an inverse correlation between ultrasonic frequency and enhancement magnitude. When subjected to 21 kHz excitation, the Nusselt number exhibits a 33.8% enhancement while the friction factor shows a 13.66% reduction compared to baseline conditions. This synergistic effect yields 40.86% improvement in thermal-hydraulic performance. When transducers are installed at both the inlet and outlet, optimal heat transfer performance is achieved. Compared to conditions without ultrasound, the Nusselt number increases by 72%. Comparing the installation of different numbers of transducers at the inlet of the heat exchange tube, the optimal heat transfer enhancement effect was achieved when three ultrasonic transducers were installed. The Nusselt number increased by up to 88%, and the Performance Evaluation Coefficient (PEC) reached its maximum value of 3.36. • Ultrasonic active control technology is integrated with spiral-wound heat exchangers to enhance thermal performance. • Multiple ultrasonic configurations are experimentally tested to optimize heat transfer in spiral-wound systems. • Four critical ultrasonic transducers parameters (frequency, sound intensity, number, installation position) are systematically analyzed for their impact on heat exchange efficiency.