Simulation of turbulent flows in an impingement dryer by an extended κ–ε model Original Research Article

Results of numerical simulation of 2D and 3D flow field in a single slot jet discharging tangentially into a confined cylinder are presented. This geometry is relevant to new impingement dryers. An extended κ–ε turbulence model with a near-wall function treatment is used to simulate turbulent jet flows. A finite element weighted residual method is used to solve the governing mass, momentum, turbulent kinetic energy and turbulent kinetic energy dissipation equations. The computations were performed for the Reynolds number ranging from 3200 to 31 900. Slot width is varied from 0.5 to 1.0 cm. To verify the algorithm, numerical tests were performed to ensure that the solutions were “grid independent”. The mesh was constructed with four-node quadrilateral elements. Flow fields, velocity profiles, jet trajectories, recirculating flows and geometry effects were investigated. Recirculating flows were found for Reynolds lower than 6300. Desired velocity profiles were found for Reynolds upper than 15 000 with slot width of 1.0 cm.