Abstract:

Numerical analysis has been performed to evaluate the heat transfer characteristics and per-formance of a circular pipe with geometrical dimple patterns. Using computational fluid dy-namics (CFD) codes, we examine the effects of geometrical configurations on the flow and thermal behavior of circular pipes with concavity (dimple) diameters. Fluid mixing and flow perturbation are facilitated by perforations across the pipe core and wall regions, thereby im-proving thermal efficiency. In addition, a concavity with a diameter of 4 mm enhances heat transfer. Based on the results of the study, the disrupted pipe wall and pipe core region pro-duce swirls and transverse vortices in the flow that provide superior heat transfer compared to conventional (smooth) pipes. In an increasing Reynolds number (Re), mixing, secondary, and separation flows become larger. Performance evaluation factor (PEF) values increased at low Reynolds numbers when dimple diameter was 1mm. As a result of these improved pipes, heat exchanger efficiency may improve in industrial applications, a key factor for energy con-servation.

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