Flow Maldistribution in Multichanneled Microdevices With In-Line Manifolds

2009 ◽  
Author(s):  
J. Soman ◽  
B. Mathew ◽  
T. J. John ◽  
H. Hegab
Keyword(s):  
Fluid Flow ◽  
Microfluidic Device ◽  
Flow Rate ◽  
Flow Characteristics ◽  
Flow Distribution ◽  
Simulation Software ◽  
Channel Width ◽  
Computational Time ◽  
Specific Flow ◽  
The Difference

This paper deals with the analyses of fluid flow distribution in a microfluidic device with in-line manifolds. The analysis was performed using commercially available microfluidic simulation software called CoventorWare™. The number of channels in the microfluidic device considered for this study was kept at ten due to limitations on the number of nodes and computational time. Channels with only square profile were analyzed for flow rates varying between 1 to 60 ml/min. The length of the channels was maintained at 1.5 cm for all simulations. The fluid flow distribution characteristics for different channel widths/depths (200, 100, and 75 μm) were investigated. It was observed that the flow rate decreased from the central channels to the outer channels. The flow per channel was symmetric about the geometric centre of the microdevice. The uniformity in flow was accessed using the root mean square value of flow per channel and it decreased with decrease in channel width/depth for a specific flow rate. The difference in the flow rate through the channels increased with increase in total flow rate. Similarly, the spacing between the channels was varied (300, 200, and 100 μm) for a microdevice with channel width/depth of 100 μm and its corresponding flow characteristics were studied for flow rate ranging between 1 ml/min and 60 ml/min. Finally, the length of each manifold was varied between 2500 μm and 1000 μm for understanding the effect of manifold length on flow distribution. The standard deviation of flow per channel did not show much variation with changes in spacing and manifold length. In addition each design of the manifolds was analyzed on the basis of pressure and flow rate as well as velocity profile in each of the channels.

Effect of Manifold Design on Flow Distribution in Multichanneled Microfluidic Devices

2009 ◽  
Author(s):  
B. Mathew ◽  
T. J. John ◽  
H. Hegab
Keyword(s):  
Microfluidic Device ◽  
Flow Rate ◽  
Flow Distribution ◽  
Paper Analysis ◽  
Channel Width ◽  
Total Flow ◽  
Total Flow Rate ◽  
Proper Selection ◽  
Channel Spacing ◽  
Selection Of

The effect of channel width and channel spacing on the flow distribution in a microfluidic device with U-type manifolds is numerically analyzed in this paper. Analysis is performed for flow rates between 1 ml/min and 60 ml/min. Flow distribution in a microfluidic device with three different microchannel widths are studied: 50 μm, 100 μm, and 200 μm. Reduction in the microchannel width reduced the non-uniformity in flow rate. Moreover, the flow malidistribution increased with increase in flow rate. The RMS value of the deviation of flow rate per channel reduced from 3 ml/min to 0.3 ml/min with reduction in channel width for a total flow rate of 60 ml/min. The effect of channel spacing on flow distribution was investigated for three channel spacing of 300 μm, 100 μm, and 50 μm. Reduction in channel spacing increased nonuniformity of flow distribution. The RMS value of the deviation of flow rate per flow rate reduced from 1 ml/min to 0.6 ml/min with increase in channel spacing for the greatest flow rate. From the particular studies examined in this paper it is found channel width has a stronger influence on flow distribution than channel spacing. Moreover, proper selection of channel width and channel spacing can uniformly distribute flow.

The Numerical Simulation of Flow Characteristics in T-Type Pipe

2012 ◽  
Vol 542-543 ◽  
pp. 1079-1082
Author(s):  
Yu Qin Zhu
Keyword(s):  
Numerical Simulation ◽  
Mass Flow Rate ◽  
Flow Rate ◽  
Heat Exchangers ◽  
Flow Characteristics ◽  
Flow Distribution ◽  
Simulation Software ◽  
Heating Furnaces ◽  
Fluent Simulation ◽  
Distribution Uniformity

The manifolds are flow distribution devices commonly used in the heating furnaces, heat exchangers, reactors, boilers, and so on. The flow distribution uniformity in the manifolds, to a large extent, decides the operation safety and economy of these devices. Manifolds are consisted of a number of T-type pipes, the flow characteristics in the T-type pipe takes an important role in the flow distribution non-uniformity of manifolds, so flow characteristics in T-type pipes were systematically researched and analyzed by the Fluent simulation software in this paper, exploring the influencing factors such as the inlet mass flow rate on flow distribution non-uniformity, and providing some measures to improve the flow distribution uniformity.

scholarly journals Learning The Fluid/Flow Properties Using Microfluidics

2019 ◽  
Vol 215 ◽  
pp. 10002
Author(s):  
Pooria Hadikhani ◽  
Navid Borhani ◽  
S. Mohammad H. Hashemi ◽  
Demetri Psaltis
Keyword(s):  
Neural Networks ◽  
Fluid Flow ◽  
Microfluidic Device ◽  
Flow Rate ◽  
Deep Neural Networks ◽  
Good Accuracy ◽  
Flow Properties ◽  
Flow Rates

Deep neural networks (DNN) are employed to measure the flow rate and the concentration of the liquid using the images of the droplets in a microfluidic device. The trained networks are able to measure flow rates and concentrations with good accuracy.

scholarly journals Numerical Simulation of Full-Scale Three-Dimensional Fluid Flow in an Oscillating Reactor

2021 ◽  
Vol 9 ◽  
Author(s):  
Houjun Gong ◽  
Mengqi Wu
Keyword(s):  
Numerical Simulation ◽  
Fluid Flow ◽  
Flow Field ◽  
Flow Rate ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Full Scale ◽  
Variation Patterns ◽  
Oscillating Motion ◽  
Resistance Coefficients

Marine reactors are subjected to additional motions due to ocean conditions. These additional motions will cause large fluctuation of flow rate and change the coolant flow field, making the system unstable. Therefore, in order to understand the effect of oscillating motion on the flow characteristics, a numerical simulation of fluid flow is carried out based on a full-scale three-dimensional oscillating marine reactor. In this study, the resistance coefficients of the lattice, rod buddle and steam generator are fitted, and the distribution of flow rate, velocity as well as pressure in different regions is investigated through the standard model. After additional oscillation is introduced, the flow field in an oscillating reactor is presented and the effect of oscillating angle and elevation on the flow rate is investigated. Results show that the oscillating motion can greatly change the flow field in the reactor; most of the coolant circulates in the downcommer and lower head with only a small amount of coolant entering the core; the flow fluctuation period is consistent with the oscillating period, and the flow variation patterns under different oscillating conditions are basically the same; since the flow amplitude is related to oscillating speed, the amplitude of flow rate rises when decreasing the maximum oscillating angle; the oscillating elevation has little effect on the flow rate.

scholarly journals Thermal performance for electromagnetohydrodynamic flow of non-Newtonian Casson fluid through porous microtube

2020 ◽  
Vol 9 (3) ◽  
pp. 804
Author(s):  
Motahar Reza ◽  
Amalendu Rana ◽  
Raghunath Patra
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Fluid Flow ◽  
Flow Rate ◽  
Flow Distribution ◽  
Casson Fluid ◽  
Temperature Profiles ◽  
Heat Flow Rate ◽  
Pressure Gradients ◽  
Kinetic Effects

A theoretical investigation is done to analyze the heat transfer features of non-Newtonian Casson fluid in a porous microtube with electro kinetic effects associated with the applied magnetic field. The exact analytical solutions the velocity and temperature profiles of non-Newtonian Casson fluid in porous micro-tube related to combining effects of electromagnetohydrodynamics forces and electrokinetic forces have been obtained using a variation of parameter. Temperature and flow distribution characteristics of Casson fluid flow are controlled by the obtruded pressure-gradients, applied a magnetic field and electro-kinetic forces. The exciting features of the electromagnetohydrodynamics flow along with the features of the heat flow rate are examined by variation in the non-dimensional physical arguments on velocity and temperature functions. The effect of the Casson parameter on the velocity and temperature profiles has been investigated analyzed. The fluid flow rate and the heat transfer rate of Casson fluid within porous micro-tube is controlled by the strength applied electric and magnetic field. 

scholarly journals Development of an Automated Approach for Updating of the Annual Runoff Module Map

2015 ◽  
Vol 2 ◽  
pp. 35
Author(s):  
N.V. Arefiev ◽  
N.S. Bakanovichus ◽  
A.A. Lyalina ◽  
N.V. Sudakova ◽  
T.S. Ivanov ◽  
...  
Keyword(s):  
Flow Rate ◽  
River Flow ◽  
Flow Characteristics ◽  
Flow Distribution ◽  
Computer Assisted ◽  
Gis Application ◽  
North West ◽  
Hydrological Data ◽  
Hydropower Potential

<p>Several Russian Hydropower Design and Research Institutes have recently fulfilled studies of hydropower potential estimation for NorthWest, Caucasian and Angara River’s regions in Russia. An approach to automate the calculation of river flow characteristics, based on the usage of annual flow rate map, was proposed and tested by the authors for the aims of the studies.</p><p>Annual river flow characteristics together with the terrain data are the most important data sources for evaluation of the hydropower potential.</p><p>A set of requirements was made for the approach and for automation of annual flow rate maps creation in order to provide ability for updates in every 5-10 years.</p><p>A problem of lack of hydrological data for small and medium sized rivers was faced. To determine the hydrological characteristics the Russian code specification "Determination of Design Hydrological Performance" was used for the conditions of the lack of hydrological data, methods of spatial interpolation were also used.</p><p>To solve the problems it is necessary to define the parameters of the annual flow distribution: average annual flow, variation coefficient, coefficient of skewness.</p><p>Mapping is based on the assumption of a smooth change of annual flow rate for any territory in accordance with the distribution of climatic and physiographic factors (topography, soil, groundwater depth, etc.).</p><p>Milestones of flow rate mapping included: preparation of hydrological initial data; creating of the updated flow rate maps; determination of the corrections to the influence of local azonal factors; estimation of the accuracy of flow characteristics calculations.</p><p>In order to update the annual flow rate maps a special GIS application “Hydrologist” was created. The GIS application includes computer-assisted tool for processing the hydrological data, import/export tools, tools for analysis of area zoning data, tools for analysis of annual flow rate values in centroids of drainage-basins, location of water stage gauges, also the old and updated flow rate maps.</p><p>The article deals with the approach description, main problems that were faced and presenting the results.</p><p>The technology has been applied for North-West, Volga and Siberian Federal Districts in Russia. Comparison of the created annual flow rate map with the previously used map shows that the updated map is better of acquiring hydrological data for small and medium sized rivers.</p>

Flow Characteristics of Gerotor Motors with Pin and Nonpin Designs

2022 ◽  
Author(s):  
Chiu-Fan Hsieh ◽  
Tehseen Johar ◽  
Yi-Hao Lin
Keyword(s):  
Fluid Flow ◽  
Flow Rate ◽  
Flow Characteristics ◽  
Geometric Design ◽  
Performance Quality ◽  
Output Torque ◽  
Computational Fluid Dynamics Cfd ◽  
The Stability ◽  
Comparison Of The Results ◽  
Velocity Pressure

Abstract The geometric design of a gerotor motor has a significant impact on its function, performance, quality, reliability and cost. When designing a gerotor motor all these features must be considered. A gerotor motor can be classified into two types based on the geometric design; gerolor (pin design) and gerotor (nonpin design). In this article geometric parameters of the two design types are discussed briefly and the operation of the gerotor motor is described as well. A numerical analysis is carried out by using computational fluid dynamics (CFD) tool (PumpLinx) to analyze the fluid flow and predict the performance of both types of gerotor designs. Various characteristics of the two designs of the gerotor motor are investigated and compared which include the gerotor design, fluid flow rate, velocity, pressure and output torque. Comparison of the results found out that using pin design gerotor motor, the flow rate, flow velocity, pressure and torque will vary greatly. Nonpin design can significantly reduce variations in all the flow characteristics thereby enhancing the stability and reduction in the leakage risk.

scholarly journals Numerical and Experimental Study of Flow Characteristics in Solar Collector Manifolds

Energies ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1431 ◽  
Author(s):  
Panagiotis Karvounis ◽  
Dimitrios Koubogiannis ◽  
Elias Hontzopoulos ◽  
Antonios Hatziapostolou
Keyword(s):  
Flow Rate ◽  
Solar Collector ◽  
Flow Characteristics ◽  
Flow Distribution ◽  
Computational Grids ◽  
Forced Circulation ◽  
Efficient Operation ◽  
Rate Distribution ◽  
Flow Models ◽  
Cfd Method

The flow through a forced circulation Z-type flat plate solar collector was investigated by means of combined experimental measurements and numerical simulations. The efficient operation of such collectors depends on the uniformity of the flow rate distribution among their riser tubes, while low pumping power demand is also sought. Mass flow rate measurements in the riser tubes were performed, utilizing a specially adapted ultrasound instrument for various values of total flow rates in the collector. By means of a commercial Computational Fluid Dynamics (CFD) code, laminar and turbulent flow models in different computational grids were tested and validated against the experiments. Appropriate metrics were introduced to quantify flow rate distribution non-uniformity among the risers, and pressure drop through the manifold was calculated. Parametric studies for flow conditions outside the experimental window were performed utilizing the CFD method in order to assess the effect of the Reynolds number in the flow distribution among the riser tubes. Furthermore, aiming to enhance flow rate uniformity, a methodology based on modifying the diameter of each riser tube was applied and successfully demonstrated. The proposed method can be employed in large solar collector arrays, either as stand-alone systems or as belonging to hybrid alternative sources of energy (ASE) systems, aiming to optimize their overall efficiency.

CFD Simulation of Flow Characteristics in Liquid-Liquid Ejectors

2013 ◽  
Vol 785-786 ◽  
pp. 1164-1167
Author(s):  
Yan Zhang ◽  
Yang Dong Hu ◽  
Lian Ying Wu
Keyword(s):  
Flow Velocity ◽  
Secondary Flow ◽  
Flow Rate ◽  
Cfd Simulation ◽  
Velocity Ratio ◽  
Flow Characteristics ◽  
Flow Distribution ◽  
Mass Rate ◽  
Turbulent Dissipation ◽  
Feed Angle

Computational Fluid Dynamics (CFD) technique was employed to investigate the flow regime and pattern in liquid-liquid ejectors. The results show that the turbulent dissipation rate decreases initially and then increases with the increase of the secondary flow mass rate at a fixed working flow rate, and increases as the working flow mass rate increases at a fixed secondary flow rate. The shape of the flow distribution is convex when the ratio of suction flow velocity to jet flow velocity (velocity ratio) is 0.25,while the shape is concave at the ratio of 4. In addition, the deflection of the flow field inside ejectors is affected by the variation of secondary flow feed angle. There exists an angle of about 24°, at which the flow pattern would be relatively reasonable.

Computational Flow Simulation for the Entire Nano-Filter

2003 ◽  
Author(s):  
S. Nakamura ◽  
Jungwan Park
Keyword(s):  
Fluid Flow ◽  
Potential Distribution ◽  
Computational Models ◽  
Filter Design ◽  
Flow Characteristics ◽  
Flow Simulation ◽  
Flow Distribution ◽  
Design Parameters ◽  
Fluid Flow Velocity ◽  
Fluid Flow Characteristics

This paper describes the computational models to analyze fluid flow characteristics in a nano-filter made from silicon wafer, then illustrates analyses of the external and ion electric potential distribution, ion transport, and fluid flow velocity distribution. Although no optimization of the design parameters is attempted, the illustrative analyses using the computational model reveal that unless the nano-filter design is carefully optimized the flow distribution can become very nonuniform over the entire filter and thus inefficient.

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