Effect of Dimple Intrusions and Curvature Radius of Rounded Corner Triangular Duct on Fluid Flow and Heat Transfer

Abstract

The sharp corner significantly affects the flow through triangular duct. In the corners, flow gets stagnant, which results in poor heat transfer. Therefore, in the present study, one corner of the duct is kept rounded with variable curvature radius values (Rc). The curvature radius is selected in such a way that it varied from the minimum value (i.e., Rc = 0.33 times duct height; h) to a maximum value (i.e., Rc = 0.67h,which named as conventional duct in the work). In addition to this, the combined effect of both rounded corner and dimple-shaped intrusion has also been studied on flow of air and heat transfer and for this purpose; the relative streamwise distance (z/e) is varied from 6 to 14 with constant relative transverse distance (x/e) that is10. Steady-state, turbulent flow heat transfer under thermal boundary conditions is analyzed for Reynolds number from 5600 to 17,700. ANSYS (Fluent) 12.1 software is used to perform numerical simulations and good match has been observed between the simulated and experimental results. Due to rounded corner and dimple intrusions, velocity near the corner region has higher value in comparison to the conventional duct. The uniform temperature distribution is seen in the case of dimple intruded duct as compared to conventional and rounded corner duct (with Rc value of 0.33h). In comparison to conventional duct, the heat transfer increased about 21–25%, 13–20%, and 5–8%, for the Rc value of 0.33h, 0.49h, and 0.57h, respectively, but the combination of rounded corner and dimple-shaped intrusion augments heat transfer by 46–94%, 75–127%, 60–110%, for the z/e value of 6, 10, and 14, respectively, with the Reynolds number increase from 5600 to 17,700.