Experimental Study On Mixing Mechanism And Application Of Staggered Herringbone Grooves Micromixer

Typical microfluidic device is usually a chip apparatus characterized by microchannel networks and various integrated functional units,by which the main function of microfluidic device is to analyze,manipulate and study microfluids.In the field of microfluidics,the contact of different fluids is frequently encountered,so it is of much significance to effectively regulate the diffusion and mixing of the fluids to further improve the rate and efficiency of chemical analysis and reactions.The usefulness of micromixer can overcome the mixing issue resulting from the laminar flow under low Renolds numbers,and realize the homogeneous mixing flow through the micromixer,which is difficult to be accomplished by the traditional methods,so it can be widely used in the microfluidic scenarios such as biochemical reaction and material synthesis.In this paper,based on the design concept of passive micromixer,numerical simulation and experimental research are jointly utilized to design staggered herringbone grooves-based micromixer on the basis of the state-of-the-art background.The mass transfer and mixing mechanism in the fluids caused by staggered herringbone grooves is analysed,the geometric parameters and fluid conditions that mainly affect the performance of the micromixer are numerically simulated,and the influence of different parameters on the mixing effectiveness is revealed.To numerically comprehend the method of mixing enhancement provides theoretical guidance for the subsequent experimental research on flow and mixing characteristics in micromixers.The key position and overall structure of microfluidic chips are designed and fabricated by taking into consideration the improvemrnt of the mixing efficiency of micromixers and the reasonable processing technology aspects,then the microfluidic chip is fabricated using standard microfluidic soft lithography technology,and the experimental system platform is set up.Under the given experimental parameters,the pumping flowrate of the fluid introduced into the micromixer is controlled.By observing the flow and mixing of the mixed fluid and evaluating the mixing efficiency under different flow conditions,the optimum experimental parameters of the mixing efficiency are determined.In order to improve the universality of the micromixer,the mixing performance of the micromixer under different viscosity fluid conditions was also analyzed;the experimental results show that the micromixer with bilateral co-arranged staggered shaped grooves can still achieve the most effective and rapid mixing of high viscosity fluid.Thanks to the efficient mixing characteristics of staggered herringbone groovedbased micromixer,the microfluidic chip was used to synthesize fine magnesium hydroxide particles.By controlling the preparation conditions such as the reactant concentration and injection mode,magnesium hydroxide particles were prepared by single step synthesis method in the staggered herringbone grooved-based micromixer.The surface morphology of the resultant was observed under the scanning electron microscope,and the particle size of magnesium hydroxide was quantitatively analyzed as well.The results show that the magnesium hydroxide particle is fine and the prepared particles is uniformly dispersed,which can be potentially used as the flame retardant additive and finally demonstrate the feasibility of the application of the microreactor.