553 Flow and control of particle laden gas-solid Coanda jet flow

Valve-induced flow characteristics were often concerned in many fluid transportation and control industries. In this paper, the eccentric jet-flow characteristics induced by a gate valve have been studied by considering the influence of valve opening regulation. The experimental setup of monitoring the downstream pressures along the pipeline was developed, and corresponding numerical simulation was employed. The downstream-monitoring pressure distribution caused by valve opening regulation was investigated to verify the flow simulation. The generation mechanism of eccentric jet-flow was revealed as a strong pressure gradient caused by the throttling effect at the valve throat. It was found that the eccentric jet-flow evolved in the pipeline was accompanied by shearing vortices, extremely under a small valve opening. The pressure and axial velocity distributions at various downstream cross-sections of the eccentric jet-flow evolving in the pipeline were analyzed. The axial velocities on four monitoring lines in downstream cross-sections were extracted, and the radial location of the maximum axial velocity was derived to assess the eccentric characteristics of jet-flow. A dimensionless parameter of velocity eccentric ratio was introduced to quantify the eccentric intensity of the evolving jet-flow in the downstream pipeline, and its correlation with the pipeline length could be adequately expressed by a natural decreasing exponential curve via fitting analysis. By virtue of that correlation, the critical pipeline length was proposed that can be used as the judgment to the terminal of the eccentric jet-flow evolving in the downstream pipeline. This study was helpful to characterize the valve-induced flow characteristics in scientific research and provide useful insight into fluid and mechanical engineering.

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Measurements and Control of Flow Oscillation Induced by a Cylinder Placed in a Two-Dimensional Turbulent Jet

Volume 1: Fora, Parts A, B, C, and D ◽

10.1115/fedsm2003-45236 ◽

2003 ◽

Author(s):

Masato Fujii ◽

Masaharu Matsubara ◽

Takashi Yoshida ◽

Toshihiko Ikeda ◽

Yoshiaki Tsuchiya

Keyword(s):

Turbulent Flow ◽

Jet Flow ◽

Natural Oscillation ◽

Two Dimensional ◽

Sound Emission ◽

Mean Velocity ◽

Free Jet ◽

Air Jet ◽

Oscillation Process ◽

And Control

An experimental study is presented of the jet flow, effusing with a velocity profile of developed turbulent flow, and of the flow control by means of sound emission. The impinging distance, defined as the distance between the exit and the cylinder, is xi, the slit width h is 10mm, and the cylinder diameter d is 20mm. The exit velocity of two-dimensional turbulent air jet is settled at 20m/s. Measurements include pressures around the cylinder, and the velocity of the jet flow. An oscillation of impinging jet is induced by inserting a cylinder over a range of the impinging distance, 3 < xi/h < 10, even when the jet effuses with a profile of developed turbulent flow. At the impinging distance of xi/h = 8, the oscillation process of mean velocity field is shown by means of the contours of mean velocity and arranged as an animation. The sound emission with the same frequency as that of natural oscillation stabilizes the periodic motion of the original oscillation. The jet flow is controlled to oscillate at a deviated frequency in the case when the intense sound was emitted within an extent of frequency deviation from the natural frequency. The flow with two peak frequencies, observed in the spectrum at xi/h = 10, is also controlled by emitting the sound with either of the frequencies. The free jet, effusing with a profile of developed turbulent flow, might be controlled by various frequencies.

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Coanda Jet Flow along Circular Cylinder and Its Control by sub Jet

The proceedings of the JSME annual meeting ◽

10.1299/jsmemecjo.2003.2.0_153 ◽

2003 ◽

Vol 2003.2 (0) ◽

pp. 153-154

Author(s):

Toshihiko SHAKOUCHI ◽

Takuya SUGIYAMA ◽

Koichi TSUJIMOTO ◽

Toshitake ANDO ◽

Takeshi ISHIZUKA

Keyword(s):

Circular Cylinder ◽

Jet Flow ◽

Coanda Jet

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Flow Characteristics of Particle-Laden Coanda Jet Flow and Classification

The Proceedings of Conference of Kansai Branch ◽

10.1299/jsmekansai.2002.77._9-13_ ◽

2002 ◽

Vol 2002.77 (0) ◽

pp. _9-13_-_9-14_

Author(s):

Toshihiko SHAKOUCHI ◽

Satoshi TERASHIMA ◽

Toshitake ANDO ◽

Takuya SUGIYAMA

Keyword(s):

Flow Characteristics ◽

Jet Flow ◽

Coanda Jet

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Computational Study on the Aerodynamic Performance of Wind Turbine Airfoil Fitted with Coandă Jet

Journal of Renewable Energy ◽

10.1155/2013/839319 ◽

2013 ◽

Vol 2013 ◽

pp. 1-17 ◽

Cited By ~ 10

Author(s):

H. Djojodihardjo ◽

M. F. Abdul Hamid ◽

A. A. Jaafar ◽

S. Basri ◽

F. I. Romli ◽

...

Keyword(s):

Wind Turbine ◽

Computational Study ◽

Three Dimensional ◽

Aerodynamic Performance ◽

Cfd Modeling ◽

Trailing Edge ◽

Optimum Configuration ◽

Wind Turbine Airfoil ◽

Coanda Jet ◽

And Control

Various methods of flow control for enhanced aerodynamic performance have been developed and applied to enhance and control the behavior of aerodynamic components. The use of Coandă effect for the enhancement of circulation and lift has gained renewed interest, in particular with the progress of CFD. The present work addresses the influence, effectiveness, and configuration of Coandă-jet fitted aerodynamic surface for improving lift andL/D, specifically for S809 airfoil, with a view on its incorporation in the wind turbine. A simple two-dimensional CFD modeling usingk-ɛturbulence model is utilized to reveal the key elements that could exhibit the desired performance for a series of S809 airfoil configurations. Parametric study performed indicates that the use of Coandă-jet S809 airfoil can only be effective in certain range of trailing edge rounding-off radius, Coandă-jet thickness, and momentum jet size. The location of the Coandă-jet was found to be effective when it is placed close to the trailing edge. The results are compared with experimental data for benchmarking. Three-dimensional configurations are synthesized using certain acceptable assumptions. A trade-off study on the S809 Coandă configured airfoil is needed to judge the optimum configuration of Coandă-jet fitted Wind-Turbine design.

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Numerical analysis and control of the recirculation bubble strength of turbulent confined jet flow using inlet swirl

International Journal of Engineering Science and Technology ◽

10.4314/ijest.v2i4.59192 ◽

2010 ◽

Vol 2 (4) ◽

Author(s):

M Naskar ◽

D Roy ◽

S Majumder

Keyword(s):

Numerical Analysis ◽

Jet Flow ◽

Recirculation Bubble ◽

Inlet Swirl ◽

And Control

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Control of Metal Alloy Oxidation with Electric Fields

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100071260 ◽

1973 ◽

Vol 31 ◽

pp. 164-165

Author(s):

R. R. Dils ◽

P. S. Follansbee

Keyword(s):

Electric Fields ◽

Oxidation Process ◽

Base Alloy ◽

Oxide Surface ◽

Platinum Electrodes ◽

Insulating Layer ◽

Iron Base Alloy ◽

Alloy Oxidation ◽

Aluminum Oxide Layer ◽

And Control

Electric fields have been applied across oxides growing on a high temperature alloy and control of the oxidation of the material has been demonstrated. At present, three-fold increases in the oxidation rate have been measured in accelerating fields and the oxidation process has been completely stopped in a retarding field.The experiments have been conducted with an iron-base alloy, Pe 25Cr 5A1 0.1Y, although, in principle, any alloy capable of forming an adherent aluminum oxide layer during oxidation can be used. A specimen is polished and oxidized to produce a thin, uniform insulating layer on one surface. Three platinum electrodes are sputtered on the oxide surface and the specimen is reoxidized.

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Evidence for a Blood Ganglion Barrier in the Superior Cervical Ganglion of the Rat

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100053681 ◽

1982 ◽

Vol 40 ◽

pp. 204-204

Author(s):

D. M. DePace

Keyword(s):

Blood Vessels ◽

Superior Cervical Ganglion ◽

Peripheral Nerves ◽

Time Schedule ◽

Transmission Electron ◽

Cervical Ganglion ◽

The Central Nervous System ◽

Cervical Ganglia ◽

Capillary Circulation ◽

And Control

The majority of blood vessels in the superior cervical ganglion possess a continuous endothelium with tight junctions. These same features have been associated with the blood brain barrier of the central nervous system and peripheral nerves. These vessels may perform a barrier function between the capillary circulation and the superior cervical ganglion. The permeability of the blood vessels in the superior cervical ganglion of the rat was tested by intravenous injection of horseradish peroxidase (HRP). Three experimental groups of four animals each were given intravenous HRP (Sigma Type II) in a dosage of.08 to.15 mg/gm body weight in.5 ml of.85% saline. The animals were sacrificed at five, ten or 15 minutes following administration of the tracer. Superior cervical ganglia were quickly removed and fixed by immersion in 2.5% glutaraldehyde in Sorenson's.1M phosphate buffer, pH 7.4. Three control animals received,5ml of saline without HRP. These were sacrificed on the same time schedule. Tissues from experimental and control animals were reacted for peroxidase activity and then processed for routine transmission electron microscopy.

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