Since heat exchangers are widely used in industry, enhancing their performance has long been a focus for researchers. This research introduces a new type of turbulators, called sinusoidal turbulator with alternating axis, to augment heat transfer in a double pipe heat exchanger. The turbulator follows a sinusoidal path throughout the pipe, with its primary axis rotated by specific angles. Four geometrical parameters—sine function’s frequency, sine function’s amplitude-to-pipe diameter ratio, width-to-pipe diameter ratio, and alternating axis angle—are considered, with three levels for each and five levels for Reynolds number. Using the Taguchi method, these parameters are optimized to maximize the thermal performance factor (TPF). This numerical study assumes threedimensional, steady-state, incompressible flow. Results show that increasing amplitude and width of the sine function enhances TPF, while increasing frequency negatively correlates with TPF. The optimal model features maximum amplitude and width, minimum frequency, and an alternating axis angle of thirty degrees within the studied range. The TPF for the optimal model is 1.52, representing a 52% improvement over the plain tube scenario.

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