Showing papers on "Complete mixing published in 2011"

Microfluidic baker's transformation device for three-dimensional rapid mixing.

Abstract: We developed a new passive-type micromixer based on the baker's transformation and realized a fast mixing of a protein solution, which has lower diffusion constant. The baker's transformation is an ideal mixing method, but there is no report on the microfluidic baker's transformation (MBT), since it is required to fabricate the complicated three-dimensional (3D) structure to realize the MBT device. In this note, we successfully fabricate the MBT device by using precision diamond cutting of an oxygen-free copper substrate for the mould fabrication and PDMS replication. The MBT device with 10.4 mm mixing length enables us to achieve complete mixing of a FITC solution (D = 2.6 × 10−10 m2s−1) within 51 ms and an IgG solution (D = 4.6 × 10−11 m2s−1) within 306 ms. Its mixing speed is 70-fold higher for a FITC solution and 900-fold higher for an IgG solution than the mixing speed by the microchannel without MBT structures. The Peclet number to attain complete mixing in the MBT device is estimated to be 6.9 × 104.

Complete Chaotic Mixing in an Electro-osmotic Flow by Destabilization of Key Periodic Pathlines

Abstract: The ability to generate complete, or almost complete, chaotic mixing is of great interest in numerous applications, particularly for microfluidics. For this purpose, we propose a strategy that allows us to quickly target the parameter values at which complete mixing occurs. The technique is applied to a time periodic, two-dimensional electro-osmotic flow with spatially and temporally varying Helmoltz-Smoluchowski slip boundary conditions. The strategy consists of following the linear stability of some key periodic pathlines in parameter space (i.e., amplitude and frequency of the forcing), particularly through the bifurcation points at which such pathlines become unstable.

Complete chaotic mixing in an electro-osmotic flow by destabilization of key periodic pathlines

Abstract: The ability to generate complete, or almost complete, chaotic mixing is of great interest in numerous applications, particularly for microfluidics. For this purpose, we propose a strategy that allows us to quickly target the parameter values at which complete mixing occurs. The technique is applied to a time periodic, two-dimensional electro-osmotic flow with spatially and temporally varying Helmholtz-Smoluchowski slip boundary conditions. The strategy consists of following the linear stability of some key periodic pathlines in parameter space (i.e., amplitude and frequency of the forcing), particularly through the bifurcation points at which such pathlines become unstable.

Impact of an incomplete solute mixing model on sensor network design

Abstract: Incomplete mixing models have recently been shown to better represent solute transport at junctions of pressurized water systems, compared to a complete mixing assumption. The present work incorporated an incomplete solute mixing model into a methodology for sensor network design. Water quality simulations conducted using both mixing models were carried out to generate pollution matrices that provided the input data for the set covering optimization formulation. Multiple contamination and detection scenarios were simulated by considering both a minimum hazard level of the contaminant and a maximum volume of contaminated water consumed. Examination and comparison of outcomes demonstrated that the water quality solver used may impact sensor network designs in three ways by altering: (i) the minimum number of monitoring stations required for full detection coverage, (ii) the optimal layout of stations over the water network and (iii) the detection domain of some stations.

Evaluation of Pressurized Water Diffusion in Water Treatment Process Using CFD

Abstract: : The Process of Pressurized water diffusion is mixing process by pressurized water injection with coagulate and chlo-rine water in the water treatment system. The objectives of this research were to evaluate the mixing length and diameter of diffu-sion plate and distance from injection pipe for complete mixing by using computational fluid dynamics. From the results of CFD simulation, when diameter of injection pipe is 50 mm, 100 mm and injection pressure is 5 kg/cm 2 and the diameter of inlet pipe is 2,200 mm, the complete mixing length is 4D (D: Length as diameter of inlet pipe). When diameter of injection pipe is 50 mm, the diameter of the diffusion plate in o.1D and distance from injection pipe is 0.2D, the complete mixing length is 3D that is the most short mixing length. But when diameter of injection pipe is 100 mm and mutually related the diameter, distance of diffusion plate, the complete mixing length is 4D over. Therefore, as the diameter of inlet pipe is 2,200 mm, the injection pipe 50 mm is more efficient than 100 mm.

Microfluidic passive mixing chip

Abstract: An improved device and method for passive mixing of fluids is described, and the use of the device in clinical diagnostic procedures. The mixer provides thorough mixing of a sample of blood or other fluid with an assay material, such as a diluent or a component of an assay system, in a closed system with a low and limited pressure drop. Sample size is small, typically 5 to 300 microliters. Mixing is accomplished by a combination of rotational vortex mixing due to a fluid stream coming tangent to a drain, and either or both of a second vortex mixer of opposite handedness, and a Dean mixer. Combinations of these techniques reliably provide complete mixing at low pressure drop. In a preferred usage, the microfluidic system can run a diluent continuously and inject samples at intervals, to facilitate automatic data processing of optical or other signatures of the well-mixed stream.

Improvement of Biophysical Micromixer Design

Abstract: In a passive micro-scale mixer, the complete mixing of two or more fluids within a reasonable time period plays an important role. Microfluidic transportation and effective mixing are of importance and require examination. The biophysical micromixer addressed by authors would be utilized because of its excellent ability to enlarge the interface and reduce the diffusion length during the mixing process. Here, the mixing efficiency, pressure drop and Aspect ratio (AR) at an optimal inlet Reynolds ratio will be studied. Some useful results will be addressed: First, the dimensions of A(subscript X), G(subscript X), G(subscript Y), F(subscript X), H(subscript X), H(subscript Y) and J would be effective factors when mixing the biophysical micromixer. Second, the recirculation region would play an important role in the mixing with an increment of 33.03% with respect to the original prototype because it would escalate the two-flow interaction. Lastly, the side wall effect will influence both the mixing performance and the pressure drop. An aspect ratio of AR=10 will be suggested because it exhibits the highest mixing coefficient of 0.907 and the lowest pressure drop than previous studies cases. These findings will show the greater feasibility of the biophysical micromixer being mixed in a limited space. Additionally, these results would be useful for the mixing improvement of passive micromixer.

The science of mixing and maintaining water quality in water storage tanks

Abstract: Water storage tanks and reservoirs are a critical component of distribution systems, yet they can pose a significant challenge for water utilities as they often have a negative impact on water quality. Water quality problems can develop due to low turnover and/or inadequate mixing resulting in short-circuiting. While the benefits of maximizing tank turnover to minimize water age are generally understood, it is only recently that extensive research on mixing characteristics of storage tanks has been undertaken that has provided insight on what causes water quality problems and expertise in designing inlet/outlet pipe configurations, or mixing systems, to achieve complete mixing and maintain water quality. This paper discusses the science of mixing applicable to all styles of storage tanks including circular and rectangular reservoirs, standpipes, and elevated tanks. Mixing characteristics of storage tanks are quite complex due to the closed geometry of the tank, the effect of inlet flow momentum, and the effect of buoyancy differences caused by temperature differentials. Computational Fluid Dynamics (CFD) and Physical Scale Models are utilized to illustrate the effect of various inlet configurations, inlet momentum, and temperature differentials on the mixing processes within storage tanks. The modeling results demonstrate how water quality problems develop, and how they can be corrected with a properly designed piping/mixing system.

Device for the comlete mixing of liquids

Abstract: Subject: Device destined for the complete mixing of liquids and especially for the injection and mixing of one chemical-containing solution into the main liquid's stream with no use of stirrers or other moving mechanisms. Constitution: A raw of diaphragms (2, 4, 6, 7) and an injection container (3) meant for the complete mixing of the two liquids. Advantage: Mixing of large quantity of liquids via arrangements not so far existing.