Heat transfer augmentation in a double pipe heat exchanger by tandem utilization of bubble injection and novel magnetic turbulators methods

For the purpose of enhancing the thermal efficiency of double-tube heat exchangers, a new technique has been implemented. By integrating a vibrating turbulator and bubble injection technique, this innovative method produces an added turbulence effect. This research aims to experimentally assess the thermal efficiency of employing two active methods concurrently. Different parameters were analyzed, including water flow rates ranging from 0.5 to 4 kg/min and bubble injection flow rates varying from 2 to 6 l/min, to investigate the effects on heat transfer and pressure drop with and without the magnetic turbulator. The results suggest that by incorporating bubble injection, adopting the magnetic turbulator, and simultaneously utilizing both methods, there is a significant improvement in heat transfer. In optimal scenarios, the heat transfer coefficient is amplified by 150.3% through the injection of bubbles, 328.8% through the implementation of magnetic turbulator, and 586.2% when both techniques are employed in tandem. In comparison to the smooth tube, the friction factor ratios were 6.7, 1.6, and 7.8 times higher in the specified cases. The findings indicated that the concurrent utilization of both techniques can yield an added impact on heat transfer. Ultimately, the integrated approach demonstrated a noteworthy thermal enhancement factor value of 3.49.