Assessment of heat transfer efficiency through the application of transverse waves within a double tube heat exchanger

This research presents an innovative oscillatory mechanism, specifically designed to generate transverse waves within a heat exchanger tube. Parameters including oscillation frequencies (from 20 to 50 Hz), width of the vibrating strip (from 3 and 6 mm), and the perforations on the strip oscillator with different geometries were examined. This innovative mechanism can potentially enhance heat transfer by 278.5 % and achieve a thermal efficiency factor (TEF) of 2.86 by generating transverse waves within the tube, utilizing a 6 mm wide vibrating strip at a frequency of 20 Hz. The findings indicated that elevating the vibration frequency of the vibrating strip to 50 Hz, which generates faster transverse waves, can lead to a remarkable enhancement in heat transfer, achieving an increase of 367 % compared to a smooth tube. Meanwhile, the pressure drop along the tube experienced a rise of only 240 %. In the concluding phase of the experiment, various longitudinal perforations, featuring circular, square, triangular, and oval geometries, were introduced on the strip turbulator, to minimize pressure drop. The findings indicated that the introduction of these perforations could significantly decrease the pressure drop by as much as 120 %, with only a slight decrease in the Nusselt number, which led to TEF = 3.49.