A Duct Optimization Study for a Vertical Axis Hydro-current Turbine Model

2011 ◽  
Vol 134 (2) ◽  
Author(s):  
M. Alidadi ◽  
V. Klaptocz ◽  
G. W. Rawlings ◽  
Y. Nabavi ◽  
S. Calisal
Keyword(s):  
Power Output ◽  
Numerical Optimization ◽  
Vertical Axis ◽  
Experimental Results ◽  
Maximum Power Output ◽  
Numerical Predictions ◽  
Optimization Study ◽  
Current Turbine ◽  
Turbine Model ◽  
Good Agreement

A numerical optimization study is used to design a duct for a model of vertical axis hydro-current turbine. The effects of this duct on the power output and torque fluctuations of the turbine model are then examined numerically and experimentally. Relatively good agreement was obtained between the experimental results and numerical predictions especially at higher tip speed ratios. Experimental results show an 85% increase in the maximum power output when the turbine is placed inside the duct. The numerical and experimental torque curves for the turbine also show substantial reductions in the torque fluctuations as a result of ducting.

scholarly journals Low Speed Vertical Axis Current Turbine (LS-VACT): Experimental Results

2020 ◽  
Vol 884 ◽  
pp. 012089
Author(s):  
N Muhamat Yain ◽  
A M Abdul Malik ◽  
A Ali ◽  
A S Souf-Aljen ◽  
F Behrouzi ◽  
...  
Keyword(s):  
Vertical Axis ◽  
Experimental Results ◽  
Low Speed ◽  
Current Turbine

scholarly journals Hydrodynamic Performance Analysis of the Vertical Axis Twin-Rotor Tidal Current Turbine

Water ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1694 ◽  
Author(s):  
Yong Ma ◽  
Chao Hu ◽  
Yulong Li ◽  
Lei Li ◽  
Rui Deng ◽  
...  
Keyword(s):  
Power Output ◽  
Tidal Current ◽  
Vertical Axis ◽  
Hydrodynamic Performance ◽  
Relative Distance ◽  
Output Efficiency ◽  
Simulation Results ◽  
Tidal Current Turbine ◽  
Current Turbine ◽  
Twin Rotor

The goal of this manuscript is to investigate the influence of relative distance between the twin rotors on the hydrodynamic performance of the vertical axis twin-rotor tidal current turbine. Computational fluid dynamics (CFD) simulations based on commercial software ANSYS-CFX have been performed to enhance the understanding of interactions between the twin-rotors. The interactions between the twin rotors are known to have increased the power output efficiency as a whole, and it is, therefore, of great significance to undertake deeper research. The simulation results are found to be consistent with similar research results in the literature in some aspects. The simulation results of stand-alone turbine and twin rotors are compared from three different aspects, including blade forces, power output efficiency and wake flow field. The results showed that the cyclic variations tendency of blade force coefficients of twin rotors is close to that of the stand-alone turbine. The average power output efficiency of the twin-rotors system is higher than that of the stand-alone turbine. The interactions between the turbines increase the power output of the twin turbine system as whole in a wide relative distance range. However, smaller relative distance between the twin rotors does not mean a bigger power output efficiency of such a system. The power out efficiency of such a system would decrease when the relative distance between the twin rotors exceeds the critical point. The power output of the twin rotors reaches the peak value when the ratio between the two main axis distance and diameter of the turbine is around 9/4. This research can provide a reference for the design and development of larger tidal power stations.

Novel Design of Vertical Axis Current Turbine for Low Current Speed via Finite Volume Method

2015 ◽  
Vol 74 (5) ◽  
Author(s):  
Fatemeh Behrouzi ◽  
Adi Maimun ◽  
Yasser M. Ahmed ◽  
Mehdi Nakisa
Keyword(s):  
Experimental Data ◽  
Energy Demand ◽  
Fossil Fuel ◽  
Vertical Axis ◽  
Computational Fluid Dynamics Cfd ◽  
Volume Method ◽  
Current Turbine ◽  
Novel Design ◽  
Static Torque ◽  
Good Agreement

Now a day, increasing energy demand and environmental effect of fossil fuel cause to replacing fossil fuel with renewable energy. This paper presented novel design of turbine to generate more torque to capture more energy of water and hence cause to high output power. In this work Computational Fluid Dynamics (CFD) using realize k-e turbulence model, have been used to analyses the effect of arm on the static torque and the contours of pressure in different angle of direction for vertical vane turbine. Investigation of arm effect on static torque of vertical vane turbine and comparison between turbine with arm and without arm showed the average torque in vertical vane turbine is higher than without arm. The model settings of validation study was accomplished by comparing simulation of performance of turbine Cp and Cm with the experimental data taken from Hayashi and Hara (2005),that showed realize k-e has good agreement with experimental data.

The Damage Behaviour of Composite Tube with Pin Joint Holes

2012 ◽  
Vol 622-623 ◽  
pp. 739-742
Author(s):  
Jiang Sun ◽  
Qi Xiao
Keyword(s):  
Stress State ◽  
Failure Mode ◽  
Failure Load ◽  
Filament Winding ◽  
Experimental Results ◽  
Damage Behavior ◽  
Composite Tube ◽  
Numerical Predictions ◽  
Good Agreement

The present investigation deals with the damage behavior of composite tube with pinned-joint holes made by filament winding technique. The pin-loaded holes are tailored to fail mainly with bearing mode. The main objective of the paper is to investigate the stress state and damage behavior of pin-loaded holes made by filament winding. The failure load and the failure mode are analyzed numerically and experimentally. A good agreement between experimental results and numerical predictions is obtained.

CFD Study of 2D Model of Diffuser for Harnessing Tidal Energy

2012 ◽  
Vol 482-484 ◽  
pp. 2270-2274 ◽  
Author(s):  
Nasir Mehmood ◽  
Zhang Liang ◽  
Jawad Khan
Keyword(s):  
Fluid Flow ◽  
Power Output ◽  
Tidal Current ◽  
Experimental Results ◽  
Time Investment ◽  
Tidal Turbines ◽  
Simulation Results ◽  
Tidal Current Turbine ◽  
Current Turbine ◽  
2D Model

Diffuser augmented tidal turbines are getting enormous attention due to their immense potential to increase the generated power output. Researchers around the globe are investing considerable time and financial resources in this domain. Limited research results are available for diffuser augmented tidal turbines due to their emerging nature, large and costly research and development setup, startup cost and proprietary issues. Turbine enclosed in a diffuser is based on the principle that the generated power output by a tidal turbine is directly proportional to the cube of velocity of incoming fluid flow. Thus, even a minor increase in velocity considerably increases the generated power output. The diffuser helps accelerate the incoming fluid flow. Hence, the efficiency of the turbine is significantly increased by using a diffuser. It is challenging to accelerate the incoming flow by using a diffuser due to its shape, geometry and fabrication limitations. The diffuser design requires great deal of innovation and time investment. The purpose of this paper is to present the study of 2D model of diffuser for tidal current turbine. The study involves developing a 2D CFD model of diffuser, acquiring simulation results and comparison with experimental results. The mesh is generated in ICEM followed by simulation in CFX. The simulation results are compared to experimental results and found in reasonable agreement. The research is essential to utilize CFD tools for diffuser design used for tidal current turbine.

Aerodynamic Performance of a Double-H Type Vertical-Axis Wind Turbine: Designed by a Stream-Tube and CFD Method

2011 ◽  
Vol 346 ◽  
pp. 90-95
Author(s):  
Jin Jiang ◽  
Xiong Bo Zheng ◽  
Liang Zhang ◽  
Zhi Chuan Li ◽  
Li He
Keyword(s):  
Power Output ◽  
Present Model ◽  
Vertical Axis ◽  
Aerodynamic Performance ◽  
Vertical Axis Wind Turbine ◽  
Stream Tube ◽  
Design And Optimization ◽  
Unsteady Aerodynamic ◽  
Cfd Method ◽  
Good Agreement

The thesis improves a stream-tube method based on solidity modification and CFD method used to predict both steady and unsteady aerodynamic performance of the fixed-pitch vertical-axis with double straight-blades type of turbine designed by FengFa Technology for wind conversion. Numerical results of predicting instantaneous blades forces and power output of the rotor showed good agreement with the test data, which showed that the present model is suitable for the design and optimization of such kind of turbine.

Study of Energy Harvesting Using Piezoelectric Cymbal Transducers

2011 ◽  
Vol 687 ◽  
pp. 396-401 ◽  
Author(s):  
Si Zhe Li ◽  
Li Zheng ◽  
Dan Li ◽  
Lin Ai ◽  
Zheng Zhang ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Resonance Frequency ◽  
Output Power ◽  
Stress Level ◽  
Power Output ◽  
Mechanical Vibration ◽  
Stress Conditions ◽  
Experimental Results ◽  
Cymbal Transducer ◽  
Good Agreement

The performance of harvesting energy using piezoelectric cymbal transducers has been studied from gentle mechanical vibration under different pre-stress conditions. The cymbal transducer was fixed at 12.9 mm diameter and evaluated the output power of harvesting energy under an AC force of 0.7 N. The maximum power output reached 3.7mW with a slight stress level of 0.17 N across 50 kohm resistor for the cymbal transducer at the 730 Hz. The resonance frequency of the cymbal was shifted to lower value and the harvesting energy was increased with the pre-stress increased. The analytical results were found to be in good agreement with the experimental results. It is suggested that great potential for cymbal transducers exists in energy harvesting applications.

Lateral Motion of an Axially Moving Tape on a Cylindrical Guide Surface

2007 ◽  
Vol 74 (5) ◽  
pp. 1053-1056 ◽  
Author(s):  
Bart Raeymaekers ◽  
Frank E. Talke
Keyword(s):  
Friction Coefficient ◽  
Friction Force ◽  
Bending Stiffness ◽  
Experimental Results ◽  
Lateral Motion ◽  
Lateral Bending ◽  
Lateral Tape Motion ◽  
Numerical Predictions ◽  
Axially Moving ◽  
Good Agreement

The lateral motion of a tape moving axially over a cylindrical guide surface is investigated. The effects of lateral bending stiffness and friction force are studied and the attenuation of lateral tape motion as a function of the guide radius and friction coefficient is determined. Good agreement between numerical predictions and experimental results is observed.

Measurement of Film Thickness for Continuous Fluid Flow Within a Spinning Cone

2014 ◽  
Author(s):  
Digby D. Symons ◽  
Arnaud F. M. Bizard
Keyword(s):  
Fluid Flow ◽  
Angular Velocity ◽  
Film Thickness ◽  
Industrial Process ◽  
Vertical Axis ◽  
Experimental Results ◽  
Analytical Theory ◽  
Thin Film Flow ◽  
Thickness Measurements ◽  
Good Agreement

This paper reports experimental measurements of film thickness for continuous fluid flow within a spinning cone. The results are compared to analytical theory for thin film flow and found to be in good agreement. Spinning cones are used in various industrial process machines, including spinning cone distillation columns, centrifugal film evaporators and continuous centrifugal filters. In each case a fluid is fed continuously into the centre of a conical vessel which spins about a vertical axis with the cone apex pointing downwards. The fluid acquires the angular velocity of the cone and migrates up the internal wall of the cone under centrifugal force. Knowledge of the film thickness and flow velocity is often important in order to understand other performance parameters of the process such as evaporation or filtration rates. This paper aims to aid the design of new process machines by providing a mathematical model for film thickness that is validated by experimental results. Experiments have been conducted in which the angle of cone, angular velocity and input flow rate were all varied. Film thickness measurements were obtained via a novel optical method based on photographing the displacement of a projected grid on the surface of the flow within the cone. The method has the advantages of not disturbing the flow in any way and can provide thickness measurements over the whole cone depth. Measurements are also made insensitive to any transients by use of relatively long photographic exposures. Measurements are compared to analytical theory for axisymmetric, steady state, free-surface laminar flow of a Newtonian fluid in a spinning cone. The theory assumes the flow is thin but takes account of gravity. The theoretical model is found to be in good agreement with the experimental results.

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