The effect of flow parameters on mixing degree of a three dimensional rhombus micromixer with obstacles in the middle of the mixing channel using oscillatory inlet velocities

The previous studies of authors on passive micromixers indicated that the micromixers dividing the flow to several layers, such as rhombus micromixers and micromixers with obstacles in the middle of the mixing channel, have higher mixing degree than other types. Also, using of oscillatory inlet velocities is an active method to enhance the mixing efficiency of micromixers. Therefore, in this study these two passive and active methods have been combined and a rhombus micromixer with obstacles in the middle of the mixing channel has been studied. Sinusoidal oscillatory velocities in two inlets have been applied with a phase difference of 180 degrees. The governing equations have been solved numerically using the finite volume method. The effect of Reynolds number, Strouhal number and amplitude on mixing degree has been investigated. Results show that degree of mixing decreases with Reynolds number at almost all Strouhal numbers. There is an optimum Strouhal number for each Reynolds number. Also, there is optimum amplitude and this optimum value decreases as Reynolds number increases.