scholarly journals The Effect of Flow Velocity on Microcantilever-Based Biosensors

2007 ◽  
Vol 23 (4) ◽  
pp. 353-358 ◽  
Author(s):  
M.-C. Wu ◽  
J.-S. Chang ◽  
K.-C. Wu ◽  
C.-H. Lin ◽  
C.-Y. Wu
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Flow Velocity ◽  
Cost Efficiency ◽  
Concentration Field ◽  
Microcantilever Sensors ◽  
First Order ◽  
Coupled Problem ◽  
Physical Phenomena ◽  
Microcantilever Beam

ABSTRACTThis work focuses on studying the effect of flow velocity on microcantilever-based biosensor by numerical simulation. The microcantilever sensors used in detecting biomolecules have attractive advantages like cost efficiency, real-time and ability of fabricating in array. Both rectangular and triangular shapes of a general model of microcantilever beam are considered. Several important physical phenomena are obtained. Comparing with the first order Langmuir theory, we have calculated the effect on the reactive rate, produced concentration, the distribution of concentration and deflection in the z axis by solving these physical coupled problem involving flow field, concentration field and chemical reaction on the reaction surface. It is found numerically that the transportation of analyte, reactive rate, the distribution of concentration and deflection in the z axis are all effected by changing the flow velocity. The result has shown that flow velocity is an important factor for this biosensor.

Numerical Simulation of Impacts of Different Types of Air Duct Outlets on Ventilation Efficiency

2013 ◽  
Vol 438-439 ◽  
pp. 1098-1103
Author(s):  
Chun Zi Nan ◽  
Ji Ming Ma ◽  
Luo Zhao
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Velocity Distribution ◽  
Flow Velocity ◽  
Numerical Method ◽  
Concentration Effect ◽  
Mixing Zone ◽  
Mixing Effect ◽  
Ventilation Efficiency ◽  
Different Types

To enhance the exhaust efficiency during ventilation, three types of air duct outlets were imported. According to the characteristics of velocity distribution simulated by numerical method, the flow field is divided into the mixing zone and the exhaust zone. The gradual contracted air duct outlet can enhance the mixing effect between fresh air and smoke. In the exhaust zone, however, the flow velocity on the upper section of the tunnel is weakened, which is unfavorable for smoke exhaust. Gradual expanded air duct outlet, on the contrary, may weaken the concentration effect of the airflow. The flow velocity on the upper section of the tunnel is increased in the exhaust zone, thus the flow field is more homogenized, which is in favor of smoke exhaust.

scholarly journals Parameter optimization of anti crystallization flocking drainage pipe based on flow field distribution characteristics

2021 ◽  
Vol 25 (6 Part A) ◽  
pp. 4091-4098
Author(s):  
Shiyang Liu ◽  
Kun Xiang ◽  
Feng Gao ◽  
Xuefu Zhang ◽  
Yun Li ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Velocity Distribution ◽  
Flow Velocity ◽  
Field Distribution ◽  
Parameter Optimization ◽  
Theoretical Basis ◽  
Longitudinal Direction ◽  
Distribution Characteristics ◽  
Drainage Pipe

The crystal plugging of tunnel drainage pipe seriously affects the safe and normal use of the tunnel. In order to obtain the mechanism of flocking drainage pipe anti crystal plugging based on the characteristics of flow field distribution, numerical simulation was used to optimize the parameters of flocking drainage pipe. The results show that: with the existence of fluff, the velocity in the lower part of the drainage pipe decreases by about 50%, and the velocity in the upper part increases by about 25~50%. With the increase of the length of fluff, the velocity funnel between fluffs gradually increases, the velocity distribution at the bottom of the funnel is basically unchanged, and the velocity in the upper part gradually increases. The velocity in the upper part of the flocked drainage pipe fluctuates above the fluff to a certain extent. The flow velocity in the lower part of the drainage pipe forms a flow velocity ladder in the longitudinal direction of the villus, and the width of the ladder is about 2/3 of the longitudinal spacing of the villus. The optimized parameters of 3-D flow field of flocked drainage pipe are helpful to the further improvement of indoor test, and provide theoretical basis for the mechanism of preventing crystal blockage of flocked drainage pipe.

Numerical Simulation of Micro Flow Field of Micro Injector

2011 ◽  
Vol 327 ◽  
pp. 61-65
Author(s):  
Li Li Mu ◽  
Ning Xue
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Piezoelectric Ceramic ◽  
Calculation Model ◽  
Dynamic Evolution ◽  
Micro Channel ◽  
First Order ◽  
Micro Nozzle ◽  
Vof Model ◽  
Micro Flow

In order to research the effects of digital micro droplet injected by the piezoelectric ceramic inertial driver, the calculation model of micro flow field of micro injector was established based on the VOF model of multiphase flow. The calculation selected the implicit segregated solver and the standard k-e model was used in turbulence of the micro-nozzle. The governing equation was separated in first order upwind, and solved by PISO algorithm. The flow pattern of the micro channel fluid and the dynamic evolution process of the micro droplet generation in the plus wave driving were researched.

Study of Operating Parameters’ Impact on Separation Performance of Cyclone Separator

2011 ◽  
Vol 422 ◽  
pp. 794-798
Author(s):  
Xue Ping Wang ◽  
Ying Zhang ◽  
Ju Guang Xue ◽  
Zhen Wei Zhang
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Flow Velocity ◽  
Turbulence Model ◽  
Separation Efficiency ◽  
Operating Parameters ◽  
Separation Performance ◽  
Cyclone Separator ◽  
High Concentration ◽  
Secondary Particles

The numerical simulation can be obtained by taking advantage of turbulence model of Fluent to study the gas-solid flow field of cyclone separator. The pressure of the cyclone drops increases with the enhancement of the inlet flow velocity, and the increase amplitude can become larger and larger. The separation efficiency of the cyclone enhances gradually as the increase of the flow. The increase amplitude of small and secondary particles is much lager compared with the increase amplitude of big ones. The overall separation efficiency can strengthen gradually with increasing of particles concentration as well as the each part’s efficiency. But the separation efficiency will stay in stable level when the concentration reaches a certain value with the big particles in the low concentration and small ones in a relatively high concentration.

Numerical Simulation of the Flow-Sound Interaction Mechanisms of a Single and Two-Tandem Cylinders in Cross-Flow

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
A. Mohany ◽  
S. Ziada
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Flow Velocity ◽  
Vortex Shedding ◽  
Cross Flow ◽  
Acoustic Resonance ◽  
Positive Energy ◽  
Single Cylinder ◽  
Interaction Mechanisms ◽  
Tandem Cylinders

A numerical simulation of the flow-excited acoustic resonance for the case of two-tandem cylinders in cross-flow is performed. The spacing ratio between the cylinders (L/D=2.5) is inside the proximity interference region. Similar simulation is performed for the case of a single cylinder. The unsteady flow field is simulated using a finite-volume method. This simulation is then coupled with a finite-element simulation of the resonant sound field, by means of Howe’s theory of aerodynamics sound, to reveal the details of flow-sound interaction mechanisms, including the nature and the locations of the aeroacoustic sources in the flow field. For the case of a single cylinder, acoustic resonance is excited over a single range of flow velocity. The main aeroacoustic source, which causes a positive energy transfer from the flow field to the acoustic field, is found to be located just downstream of the cylinder. For the case of two-tandem cylinders, the acoustic resonance is excited over two different ranges of flow velocity: the precoincidence and the coincidence resonance ranges. For the coincidence resonance range, the main aeroacoustic source is found to be located just downstream of the downstream cylinder, and the excitation mechanism of this resonance range is found to be similar to that of a single cylinder. However, for the precoincidence resonance range, the primary acoustic source is found to be located in the gap between the cylinders. Moreover, flow visualization of the wake structure for the two-tandem cylinders during acoustic resonance shows that for the precoincidence resonance range there is a phase shift of about 90 deg between the vortex shedding from the upstream and the downstream cylinders, which is different from the coincidence resonance range, where the vortex shedding from both cylinders seems to be in-phase.

Numerical Simulation of Flow Filed in ESP Outlet with Moving Electrode Type

2012 ◽  
Vol 485 ◽  
pp. 27-30
Author(s):  
Man Yin Hu ◽  
Yu Chao Liang ◽  
Kai Che ◽  
Guang Han ◽  
Xiang Chen
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Flow Velocity ◽  
Geometric Model ◽  
Air Flow ◽  
Flow Distribution ◽  
Simple Algorithm ◽  
Equation Model ◽  
Opening Ratio ◽  
Air Flow Velocity

The numerical simulation of 2-D flow filed in ESP with Moving Electrode Type was carried out, in which a 2-equation model was adopted to simulate the flow field and the computation based on the SIMPLE algorithm and the geometric model was meshed with GAMBIT. The numerical simulation of flow field with FLUENT came to the conclusion that the air flow distribution in the electro static precipitator will change when the opening ratio of the electrodes and the air flow velocity in operation have changed, so the result of numerical simulation was reasonable for the design and operation of the ESP with Moving Electrode Type.

The Numerical Simulation of Flow Field of Target Type Impinging Stream Nozzle Based on Fluent

2012 ◽  
Vol 490-495 ◽  
pp. 1501-1505
Author(s):  
Su Qian Yan ◽  
Xiao Fen Zhang
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Flow Velocity ◽  
External Flow ◽  
Target Type ◽  
Water Quantity ◽  
Fluent Software ◽  
Nozzle Structure

In this paper, the numerical simulation of internal and external flow field of target type impinging stream nozzle by using Fluent software is observed, the effect on nozzle atomization was obtained by simulating the size of nozzle structure（the diameter d of nozzle and distance δ between the target and plate）and pressure P (that is to say the flow velocity). The results show that: the larger the structure size and the pressure of nozzle，the better the effect of nozzle atomization.That it has superiority than the general centrifugal nozzles and can save water quantity.

Analysis on Online Mixing Performance of Jet-Mixing Apparatus

2011 ◽  
Vol 347-353 ◽  
pp. 417-421
Author(s):  
Xi Chao Xu ◽  
Bai Jing Qiu ◽  
Bin Deng ◽  
Fang Wen Jia
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Design Method ◽  
Concentration Field ◽  
Internal Flow ◽  
Test Method ◽  
Jet Mixing ◽  
Mixing Performance ◽  
Simulation And Experiment ◽  
Interior Flow

Aimed at investigating the design method and test method of jet-mixing apparatus, numerical simulation and experiment research were both used to investigate the internal flow field of jet-mixing apparatus in this article. Numerical simulation scheme for interior flow field of jet-mixing apparatus was established, CFD software Fluent was used to investigate in concentration field of jet-mixing apparatus. The concept of IOS was brought forward to evaluate the homogeneity degree of pesticide and water. Investigation both carried on area ratio effect on the mix homogeneity of the jet-mixing apparatus and the distribution of pesticide concentration in the axial and radial of mixing tube.

Numerical Simulation of a Novel Bipolar Plate Flow Field of Proton Exchange Membrane Fuel Cell

2011 ◽  
Vol 215 ◽  
pp. 19-24
Author(s):  
Chong Da Lu ◽  
Peng Fei Gao ◽  
Wei Fang Wang ◽  
Dong Hui Wen
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Flow Velocity ◽  
Proton Exchange Membrane ◽  
Model Building ◽  
Bipolar Plate ◽  
Proton Exchange ◽  
Great Sense ◽  
Exchange Membrane ◽  
Reactive Gas

This paper proposes a novel bipolar plate flow field of PEMFC with the intersectant microstructure. Numerical simulation about both the flow velocity distribution and the pressure distribution for the reactive gas were accomplished according to the model building by Pro/E, grid meshing and boundary condition specifying by Fluent. Compared to traditional serpentine flow fields, the gas pressure difference between the inlet and the outlet of this novel flow field is appropriate to promptly discharge the water produced during the operation of the PEMFC, and the flow velocity of the reactive gas among all the flow field is well-distributed, which assures reactions occurring uniformly in the flow field under the bipolar plate. All the properties of this novel flow field make a great sense to improve the integrated performance of the PEMFC.

Three-Dimensional Analysis of Partially Open Butterfly Valve Flows

1996 ◽  
Vol 118 (3) ◽  
pp. 562-568 ◽  
Author(s):  
Chendong Huang ◽  
Rhyn H. Kim
Keyword(s):  
Numerical Simulation ◽  
Numerical Analysis ◽  
Flow Field ◽  
Dimensional Analysis ◽  
Three Dimensional ◽  
Fluid Flows ◽  
Butterfly Valve ◽  
Valve Design ◽  
Incompressible Fluid Flows ◽  
Physical Phenomena

A numerical simulation of butterfly valve flows is a useful technique to investigate the physical phenomena of the flow field. A three-dimensional numerical analysis was carried out on incompressible fluid flows in a butterfly valve by using FLUENT, which solves difference equations. Characteristics of the butterfly valve flows at different valve disk angles with a uniform incoming velocity were investigated. Comparisons of FLUENT results with other results, i.e., experimental results, were made to determine the accuracy of the employed method. Results of the three-dimensional analysis may be useful in the valve design.

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