Numerical Simulation on Micromixer Based on Syntehtic Jet

2007 ◽  
Author(s):  
M. H. Liu ◽  
X. F. Zhang ◽  
X. D. Cai ◽  
Y. L. Chen
Keyword(s):  
Numerical Simulation ◽  
Numerical Simulations ◽  
Rectangular Channel ◽  
Synthetic Jet ◽  
Mixing Efficiency ◽  
Mixing Index ◽  
Inlet Velocity ◽  
Velocity Magnitude ◽  
Jet Velocity

This paper studied a concept of micromixer with a synthetic jet placed at the bottom of a rectangular channel. Due to periodic ejections from and suctions into the channel, the fluids are mixed effectively. To study the effects of the inlet velocity, the jet intensity and frequency, and the jet location on the mixing efficiency, 3-D numerical simulations of the micromixer have been carried out. It has been found that when the jet intensity and the frequency are fixed, the mixing efficiency increases when Re<50, and decreases when Re>50 with the best mixing efficiency achieved at Re=50. When the ratio of the jet velocity magnitude to the inlet velocity is taken as 10 and the jet frequency is 100Hz, the mixing index reaches the highest value. It has also been found that to get better mixing efficiency, the orifice of the synthetic jet should be asymmetrically located away from the channel’s centerline.

Characteristics of Decompression Tank Internally Pressurized with Water Using OpenFOAM

2016 ◽  
Vol 836 ◽  
pp. 3-8 ◽  
Author(s):  
Syamsuri
Keyword(s):  
Numerical Simulation ◽  
Velocity Distribution ◽  
Numerical Simulations ◽  
Pressure Distribution ◽  
Small Area ◽  
Water Storage ◽  
Storage Tanks ◽  
Velocity Magnitude ◽  
Independent Test ◽  
Simulation Results

Decompression tank is a tank in which pressurized with water. In its application decompression tank can be reservoir tank and water storage tanks which are closed. In the simulation the value of compressibility is very important for the case decompression tank. The method used is the numerical simulations using OpenFOAM software to know the results of observation the value of the pressure, density, and velocity magnitude. Simulations will be performed by varying the value of the water compressibility 4.54e-06 4.54e-07, and 4.54e-08. Before performing simulations on the main case decompression tank then first performed by grid independent test to validate the simulation results from the study by another researcher. From the results of experiments with variation of compressibility of water it can be seen that a good comparisons with numerical simulation and previous studies show the capability of this method. The greater the value compressibility water then the pressure distribution generated more widely and rapidly spreadas well as the velocity distribution. However for the distribution of the speed with greater compressibility of the velocity distribution will become more varied and occurs only in a small area.

Numerical Simulation of Fluid Mixing in Micro-Mixers

2015 ◽  
Vol 659 ◽  
pp. 671-675
Author(s):  
Supasit Prasertlarp ◽  
Sompong Putivisutisak
Keyword(s):  
Numerical Simulation ◽  
Reynolds Number ◽  
Pressure Drop ◽  
Aspect Ratio ◽  
Ultrasound Imaging ◽  
Vortex Structure ◽  
Flow Dynamics ◽  
Fluid Mixing ◽  
Mixing Efficiency ◽  
Inlet Velocity

A 3-D numerical simulation is performed to study the flow dynamics and mixing characteristics between two different kinds of fluid within T-shaped micro-mixers. Water and ethanol are selected as the mixing fluids due to its application in calibrating the ultrasound imaging equipment. The present work focuses on the effects of inlet velocity and aspect ratio of the mixing channel. The Reynolds number is varied from 0.1 to 300 and the aspect ratio in the range between 0.2 and 1. The flow of interest is laminar, steady and without chemical reaction. It is found that at low Reynolds number, the stratified flow character is presented. As the velocity inlet increases, the mixing efficiency is decreased. However, for the Reynolds number greater than 100 the mixing efficiency is increased due to the buildup vortex structure. Furthermore, when increasing the Reynolds number, the pressure drop significantly increases. Thus, it is seen that both the inlet velocity and aspect ratio significantly affect the mixing efficiency and pressure drop.

Enhancement of Heat Transfer in a Short Rectangular Channel with Substantial Deflection of Inlet Velocity from Axial Direction

2005 ◽  
Vol 36 (4) ◽  
pp. 311-318 ◽  
Author(s):  
R. Bunker ◽  
M. YA. Belen'kii ◽  
M. A. Gotovskii ◽  
B. S. Fokin ◽  
S. A. Isaev
Keyword(s):  
Heat Transfer ◽  
Rectangular Channel ◽  
Axial Direction ◽  
Enhancement Of Heat Transfer ◽  
Inlet Velocity

Numerical Simulation of MHD Turbulent Flow in a Rectangular Channel with Three-Surface-Coated Multi Layers

2010 ◽  
Vol 37 (5) ◽  
pp. 447-457
Author(s):  
Mitsuhiro Aoyagi ◽  
Hidetoshi Hashizume ◽  
Kazuhisa Yuki ◽  
Satoshi Ito ◽  
Takeo Muroga
Keyword(s):  
Numerical Simulation ◽  
Turbulent Flow ◽  
Rectangular Channel

Study on the influence of linear and nonlinear distribution of crosswind on the motion of aircraft wake vortex

2021 ◽  
pp. 095441002098743
Author(s):  
Dong Li ◽  
Ziming Xu ◽  
Ke Zhang ◽  
Zeyu Zhang ◽  
Jinxin Zhou ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Dissipation Rate ◽  
Vortex Pair ◽  
Vertical Shear ◽  
Wake Vortex ◽  
Analysis Method ◽  
Velocity Magnitude ◽  
Aircraft Wake ◽  
Linear And Nonlinear ◽  
Nonlinear Distribution

Environmental crosswind can greatly affect the development of aircraft wake vortex pair. Previous numerical simulations and experiments have shown that the nonlinear vertical shear of the crosswind velocity can affect the dissipation rate of the aircraft wake vortex, causing each vortex of the vortex pair descent with different velocity magnitude, which will lead to the asymmetrical settlement and tilt of the wake vortex pair. Through numerical simulations, this article finds that uniform crosswind convection and linear vertical shear crosswind convection can also have an effect on the strength of the vortex. This effect is inversely proportional to the cube of the vortex spacing, so it is more intense on small separation vortex pair. In addition, the superposition of crosswind and vortex-induced velocities will lead to the asymmetrical pressure distribution around the vortex pair, which will also cause the tilt of the vortex pair. Furthermore, a new analysis method for wake vortex is proposed, which can be used to predict the vortex trajectory.

scholarly journals Wind shear over the Nice Côte d'Azur airport: case studies

2013 ◽  
Vol 13 (9) ◽  
pp. 2223-2238 ◽  
Author(s):  
A. Boilley ◽  
J.-F. Mahfouf
Keyword(s):  
Numerical Simulation ◽  
Numerical Model ◽  
Numerical Simulations ◽  
Wind Shear ◽  
Horizontal Wind ◽  
Wind Profiler ◽  
Measurement Campaign ◽  
Wind Lidar ◽  
Real Time Applications ◽  
Wind Shears

Abstract. The Nice Côte d'Azur international airport is subject to horizontal low-level wind shears. Detecting and predicting these hazards is a major concern for aircraft security. A measurement campaign took place over the Nice airport in 2009 including 4 anemometers, 1 wind lidar and 1 wind profiler. Two wind shear events were observed during this measurement campaign. Numerical simulations were carried out with Meso-NH in a configuration compatible with near-real time applications to determine the ability of the numerical model to predict these events and to study the meteorological situations generating an horizontal wind shear. A comparison between numerical simulation and the observation dataset is conducted in this paper.

Stefan Number-Insensitive Numerical Simulation of the Enthalpy Method for Stefan Problems Using the Space-Time Conservation Element and Solution Element Method

2004 ◽  
Author(s):  
Anahita Ayasoufi ◽  
Theo G. Keith ◽  
Ramin K. Rahmani
Keyword(s):  
Numerical Simulation ◽  
Phase Change ◽  
Numerical Simulations ◽  
Latent Heat ◽  
Space Time ◽  
Enthalpy Method ◽  
Stefan Problems ◽  
Stefan Number ◽  
Original Scheme ◽  
Solution Element

An improvement is introduced to the conservation element and solution element (CE/SE) phase change scheme presented previously. The improvement addresses a well known weakness in numerical simulations of the enthalpy method when the Stefan number, (the ratio of sensible to latent heat) is small (less than 0.1). Behavior of the improved scheme, at the limit of small Stefan numbers, is studied and compared with that of the original scheme. It is shown that high dissipative errors, associated with small Stefan numbers, do not occur using the new scheme.

Numerical Simulation of Pulsating Flow over Blood Vessel Robot

2012 ◽  
Vol 591-593 ◽  
pp. 1734-1738
Author(s):  
Chun Yan Huang ◽  
Fan Jiang
Keyword(s):  
Numerical Simulation ◽  
Boundary Condition ◽  
Blood Flow ◽  
Blood Vessel ◽  
Surface Pressure ◽  
Blood Parameters ◽  
Pulsating Flow ◽  
Inlet Velocity ◽  
Blood Density

In order to study the influence of pulsating blood flow to robot and blood vessel, UDF programming of the inlet velocity is defined as the boundary condition, and the model simulate the turbulent blood flow. Moreover, in this situation, this paper analyzes the influence caused by blood parameters for the biggest surface pressure on robot. The results are showed that the variation of pressure and velocity is different on different position at 0.08s and 0.27s, and the surface pressure of the robot become greater by the increase of blood density or viscosity.

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