CFD analysis on heat transfer characteristics and fluid flow structure in a square duct with modified wavy baffles

Performance assessments, and flow and heat transfer patterns of a square duct attached with different six types of modified wavy baffles are presented. The influences of fluid blockage ratios or baffle heights (b = 0.05H-0.30H), flow directions (+x and -x) and baffle shapes (A - F) on augmented Nusselt number and fluid flow mechanisms are numerically studied for the laminar flow of the Reynolds number in a range of 100-2000. The simulated problem is solved with the finite volume method (commercial program) using the Semi-Implicit Method for Pressure-Linked Equations (SIMPLE algorithm). The mechanisms (streamlines across the cross-sectional planes, temperature contours, Nusselt number contours) of the tested duct are focused. From the simulated results, the vortex flows are observed to be the main point for the heat transfer increment for all investigated cases. Over the investigated range, the greatest Nusselt number is found to be around 20.10 times higher than that of the plain duct. The maximum TEF of 3.70 is shown at b = 0.10H of the type D modified wavy baffle with the +x flow direction.