Numerical Analysis Of Turbulent Forced-convection Flow In A Channel With Staggered L-shaped Baffles

Characteristics of fluid flow and heat transfer are analyzed for a constant property fluid flowing turbulently through a twodimensional horizontal rectangular cross section channel with staggered, transverse L-shaped baffles (STLBs) and a constant temperature along both walls. The Commercial CFD software FLUENT 6.3 is used to simulate the fluid flow and heat transfer fields. As a part of the same package, a preprocessor Gambit is used to generate the required mesh for the solver. The governing equations, based on the Shear Stress Transport (SST) k-ω model used to describe the turbulence phenomena, are discretized using the Finite Volume Method (FVM) with Semi Implicit Method for Pressure-Linked Equations (SIMPLE) algorithm for pressure-velocity coupling. Air is the working fluid with the flow rate in terms of Reynolds numbers ranging from 12,000 to 30,000. The effects of the baffle L-shape as well as Reynolds numbers are examined. A detailed description of turbulent heat transfer flow behaviors around the STLBs was presented. In particular, contour plots of velocity and pressure fields, axial velocity profiles, local and average heat transfer coefficients, and friction loss evaluations were obtained at constant wall temperature condition along the top and bottom channel walls. The numerical results are validated with available rectangular-baffle measured data and found to agree well with measurement. The results reveal essentially, that the flow pattern of using STLBs is characterized by strong deformations and large recirculation regions. The highest values in the velocity and pressure fields are found near the top channel wall with an acceleration process that starts just after the second STLB. Also, an increase in the Reynolds number causes a substantial increase in the Nusselt number but the pressure loss is also very significant.