NUMERICAL STUDY OF PASSIVE MIXING IN A 3-D HELICAL MICROMIXER HAVING BOTH INLETS AT OFFSET WITH WATER AND BLOOD AS FLUIDS

Abstract

The mixing of Newtonian fluid water and non-Newtonian fluid blood are numerically investigated in two different micromixers. The present study tackles the problem of time-consumption in mixing at the micro-level by introducing a micromixer named 3D helical micromixer having two inlets at offset (TDHM-TO). It is concluded that this micromixer requires comparatively less mixing channel length and provide much better efficiency than a Simple T-micromixer (STM). A detailed work has been done to examine the mixing process and performance, various streamlines, effective Reynolds numbers/mass flow rate for both the micromixers, and pressure drop by solving Navier Stokes, species transport, and continuity equations for Reynolds numbers (8-400). In the case of water as working fluid, for all ranges of Reynolds numbers, helical micromixer performed better than STM. TDHM-TO provides maximum efficiency of 97.32% at Re= 310 and minimum efficiency of 79.95% at Re= 8. STM shows comparatively poorer results with a mixing efficiency of just 43.23% at Re= 410. The study with blood considers a wide range of mass flow rates (0.0004 kg/hr. – 0.10 kg/hr.). It is being found that, for all values of mass flow rate, TDHM-TO performed much better than STM. E.g., for flow rate= 0.07 kg/hr., TDHM-TO provide a mixing efficiency of 74.41% compared to 4.93 of STM which is about 65.2% more than that of STM. STM showed a very poor result compared to TDHM-TO with only 7.64% of maximum mixing efficiency obtained with the flow rate= 0.1 kg/hr. compared to 72.84% of TDHM-TO. This TDHM-TO micromixer can be, thus, utilized in many chemicals, biochemical, and biomedical industries because of its higher efficiency and lower mixing length.