Computational investigation of flow fields and erosion in a dimpled channel

A numerical prediction of flow in a dimpled channel is reported. The flow regimes considered cover a wide range of Reynolds numbers, which range from 380 to 99000 and which are equivalent to a range of inlet velocities from very low (0.072 m/s) to very high (60 m/s). In this study, calculations were made using the standard k-e model with standard wall function. The drag coefficient, skin friction drag, pressure drag, and pressure distribution around a dimple were investigated. As the velocity increased, the drag coefficient decreased until the velocity exceeded 45 m/s, after which it increased. Furthermore, the pressure drag and skin friction drag depend on the velocity. Particles with a density of 2440 kg/m3 and a diameter of 100 microns were tracked through the domain to estimate the frequency, velocity, and angle of impact of the particles and to estimate the resulting erosion rate. It was found that the maximum erosion rate occurred between 40 and 65 degrees from the leading edge of the dimple. Furthermore, a computational study of the flow fields of three dimples in an in-line arrangement is presented. This study showed that similar flow behaviours exist between the first and second dimples and that the flow behaviours are identical between the second and third cylindrical dimples.