Study of fluid flow in micromixer with symmetrical and asymmetrical inlet conditions

Flow regimes and mixing pattern in a T-type micromixer at high Reynolds numbers were studied by numerical solution of the Navier-Stokes equations and by micro-PIV and micro-LIP experimental measurement. The Reynolds number was varied from one to one thousand. The cross section of the mixing channel was 200 mu mx400 mu m and its length was 3000 mu m. Five different flow regimes were identified: (i) stationary vortex-free flow (Re < 5); (ii) stationary symmetric vortex flow with two horseshoe vortices (5 < Re < 150); (iii) stationary asymmetric vortex flow (150 < Re < 240); (iv) nonstationary periodic flow (240 < Re < 400); (v) stochastic flow (Re >400). Maximum mixing efficiency was obtained for stationary asymmetric vortex flow. In this case, an S-shaped vortex structure formed in the flow field. Also the numerical investigation of flow and mixing in the T-shaped micromixer with asymmetrical inlet conditions for different Reynolds numbers was carried out. The good agreement between calculation and experiment was obtained as a result.