scholarly journals THE ANALYSIS OF FLUID DYNAMICS OF WAVE POWER STATION WITH WELLS TURBIN BY CFD

2020 ◽  
Vol 57 (6A) ◽  
pp. 1
Author(s):  
Thien Tich TRUONG ◽  
Sang Quang Nguyen ◽  
Bang Kim Tran
Keyword(s):  
Fluid Dynamics ◽  
Renewable Energy Sources ◽  
Axial Flow ◽  
Navier Stokes ◽  
Natural Vibrations ◽  
Wells Turbine ◽  
Navier Stokes Equation ◽  
Air Chamber ◽  
Natural Energy ◽  
Blade Shape

Natural energy such as wind, wave and other natural vibrations is one of the high potential renewable energy sources. The Wells turbine is based on the use of bidirectional turbines, which act as axial-flow self-rectifying turbines that employs a symmetrical blade profile and rotating unidirectionally in reciprocating airflows generated by the air chamber to extract energy from vibrations. These topics have been extensively studied both numerically and experimentally such as research on the parameters of the effects of structure, angle of attack, blade shape, etc. In this paper, numerical simulation is carried out using commercially available tool Fluent for fluid dynamics analysis and focus on oscillating predictions, with particular attention to the behavior of the flow. Based on the Numerical Wave Tank (NWT) model is simulated in a two dimensional used in this model, which is constructed mainly based on the spatially averaged Navier Stokes equation with the k-ε model for simulating the turbulence and modeled with Volume of Fluid (VOF). Axial-flow turbines system and future development as well as the proposed limitations will be discussed in detail.

scholarly journals THE ANALYSIS OF FLUID DYNAMICS OF WAVE POWER STATION WITH WELLS TURBIN BY CFD

2020 ◽  
Vol 57 (6A) ◽  
pp. 1
Author(s):  
Truong Tich Thien ◽  
Sang Quang Nguyen ◽  
Bang Kim Tran
Keyword(s):  
Fluid Dynamics ◽  
Renewable Energy Sources ◽  
Axial Flow ◽  
Navier Stokes ◽  
Natural Vibrations ◽  
Wells Turbine ◽  
Navier Stokes Equation ◽  
Air Chamber ◽  
Natural Energy ◽  
Blade Shape

Natural energy such as wind, wave and other natural vibrations is one of the high potential renewable energy sources. The Wells turbine is based on the use of bidirectional turbines, which act as axial-flow self-rectifying turbines that employs a symmetrical blade profile and rotating unidirectionally in reciprocating airflows generated by the air chamber to extract energy from vibrations. These topics have been extensively studied both numerically and experimentally such as research on the parameters of the effects of structure, angle of attack, blade shape, etc. In this paper, numerical simulation is carried out using commercially available tool Fluent for fluid dynamics analysis and focus on oscillating predictions, with particular attention to the behavior of the flow. Based on the Numerical Wave Tank (NWT) model is simulated in a two dimensional used in this model, which is constructed mainly based on the spatially averaged Navier Stokes equation with the k-ε model for simulating the turbulence and modeled with Volume of Fluid (VOF). Axial-flow turbines system and future development as well as the proposed limitations will be discussed in detail.

scholarly journals Mixing Performance of Counter-Axial Flow Impeller using Computational Fluid Dynamics

2018 ◽  
Vol 8 (02) ◽  
Author(s):  
Ian Torotwa ◽  
Changying Ji
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Axial Flow ◽  
Turbulence Models ◽  
Navier Stokes ◽  
Navier Stokes Equation ◽  
Ansys Fluent ◽  
Rushton Turbine ◽  
Mixing Performance ◽  
Computational Fluid Dynamics Cfd

In this study, turbulent flow fields in a baffled vessel stirred by counter-axial flow impeller have been investigated in comparison to the Rushton turbine. The resultant turbulence was numerically predicted using computational fluid dynamics (CFD). Turbulence models were developed in ANSYS Fluent 18.1 solver using the Navier-Stokes equation with the standard k-ε turbulence model. The Multiple Reference Frame (MRF) approach was used to simulate the impeller action in the vertical and horizontal planes of the stirred fluid volume. Velocity profiles generated from the simulations were used to predict and compare the performance of the two designs. To validate the CFD model, the simulation results were compared with experimental results from existing work and a satisfactory agreement was established. It was concluded that the counter-axial flow impeller could provide better turbulence characteristics that would improve the quality of mixing systems.

Numerical and Experimental Study of Cooling Fan Noise

2014 ◽  
Vol 592-594 ◽  
pp. 1930-1934
Author(s):  
G.V.R. Seshagiri Rao ◽  
V.V. Subbarao ◽  
C. Prabakara Rao
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Experimental Studies ◽  
Axial Flow ◽  
Field Analysis ◽  
Navier Stokes ◽  
Axial Flow Fan ◽  
Navier Stokes Equation ◽  
Volume Method ◽  
Physical Features

Abstract. This paper presents the results of experimental studies of the noise of marine application pump axial flow fan. Axial flow fan is verified by both geometrical and experimental approaches. This section includes grid system used in geometric simulation, and boundary conditions. In order to know the complicate and complex physical features of an axial flow fan, a commercial computational fluid dynamics code, FLUENT, is utilized to perform the flow field analysis, which solves the Navier–Stokes equation using an amorphous finite volume-method. As a commercial computational fluid dynamics code, FLUENT has been extensively used in many turbo machinery applications. In this paper the noise predicted according to geometrical results will be compare with investigational results.

scholarly journals Effect of Blade Profiles on the performance of Bidirectional Wave Energy Turbine

2018 ◽  
Vol 172 ◽  
pp. 06002
Author(s):  
P.Madhan Kumar ◽  
Abdus Samad
Keyword(s):  
Wave Energy ◽  
Three Dimensional ◽  
Aerodynamic Characteristics ◽  
Navier Stokes ◽  
Wells Turbine ◽  
Reference Case ◽  
Navier Stokes Equation ◽  
World Energy ◽  
Entrapped Air ◽  
Experimental Values

To fulfill the ever growing demands of world energy consumption, the wave energy should be extracted economically. The oscillating water column is most commonly used to xtract energy from waves. It consists of a chamber in which waves drives the entrapped air column to rotate the Wells turbine. The Wells turbine is a self-rectifying low-pressure axial reaction turbine with 90ο stagger angle. These turbines consist of symmetrical airfoil profile to achieve unidirectional rotation for the bi-directional airflow. The turbine performance predominantly depends on the aerodynamic characteristics of the airfoil profile used. In this study, the performance of Wells turbine with various symmetrical airfoil profiles was analysed using ANSYS CFX 14.5. The CFD analysis was performed by solving three dimensional steady Reynolds averaged Navier-Stokes equation with k-ω SST turbulence closure model. The reference geometry has NACA0015 as blade profile and the CFD results were compared with the experimental values. The performance characteristics of the new airfoil profiles were compared with the reference case to analyse the suitability of airfoils in wave energy extraction. The NACA0021 airfoil profile showed better performance in the post-stall regime compared to the NACA0015 and the S1046 airfoil profiles.

Axial Leakage Flow-Induced Vibration of a Thin Cylindrical Shell With Respect to Axisymmetric Vibration

2003 ◽  
Vol 125 (2) ◽  
pp. 151-157 ◽  
Author(s):  
Katsuhisa Fujita ◽  
Atsuhiko Shintani ◽  
Masakazu Ono
Keyword(s):  
Cylindrical Shell ◽  
Axial Flow ◽  
Navier Stokes ◽  
Leakage Flow ◽  
Axisymmetric Vibration ◽  
Thin Cylindrical Shell ◽  
Flow Induced Vibration ◽  
Navier Stokes Equation ◽  
Coupled Equations ◽  
Stiffness Matrices

In this paper, the stability of a thin cylindrical shell subjected to axial leakage flow is discussed. In this paper, the first part of a study of the axial leakage flow-induced vibration of a thin cylindrical shell, we focus on axisymmetric vibration, that is, the ringlike vibration of a shell. The coupled equations between a shell and a fluid are obtained by using the Donnell’s shell theory and the Navier-Stokes equation. The added mass, added damping and added stiffness matrices in the coupled equations are described by utilizing unsteady fluid forces on a shell. The influence of the axial flow velocity on the unstable phenomena is clarified concerning axisymmetric vibration mode of shell. The numerical calculations are performed taking the dimensions of shell and fluid as parameters.

Computation of Three-Dimensional Turbulent Turbomachinery Flows Using a Coupled Parabolic-Marching Method

1988 ◽  
Vol 110 (4) ◽  
pp. 549-556 ◽  
Author(s):  
K. R. Kirtley ◽  
B. Lakshminarayana
Keyword(s):  
Boundary Layers ◽  
Three Dimensional ◽  
Axial Flow ◽  
Suction Side ◽  
Navier Stokes ◽  
Compressor Cascade ◽  
Navier Stokes Equation ◽  
Pressure Losses ◽  
Compressor Rotor ◽  
Marching Method

A new coupled parabolic-marching method was developed to compute the three-dimensional turbulent flow in a turbine endwall cascade, a compressor cascade wake, and an axial flow compressor rotor passage. The method solves the partially parabolized incompressible Navier–Stokes equation and continuity in a coupled fashion. The continuity equation was manipulated using pseudocompressibility theory to give a convergent algorithm for complex geometries. The computed end-wall boundary layers and secondary flow compared well with the experimental data for the turbine cascade as did the wake profiles for the compressor cascade using a k–ε turbulence model. Suction side boundary layers, pressure distributions, and exit stagnation pressure losses compared reasonably well with the data for the compressor rotor.

Performance Analysis of Wells Turbine With Radiused Blade Tip

2018 ◽  
Author(s):  
P. Madhan Kumar ◽  
Paresh Halder ◽  
Abdus Samad
Keyword(s):  
Separation Bubble ◽  
Three Dimensional ◽  
Axial Flow ◽  
Peak Torque ◽  
Aerodynamic Characteristics ◽  
Tip Leakage Flow ◽  
Wells Turbine ◽  
Navier Stokes Equation ◽  
Operating Range ◽  
Blade Tip

A Wells turbine is an axial flow reaction turbine, which consists of a symmetrical airfoil at 90° stagger. It is commonly used as a power take-off device in the oscillating water column. This turbine is prone to stall at higher flow coefficients and have narrow operating range. There are several parameters, which influence the stall characteristics of the turbine, one of them is the tip leakage flow. Radiused blade tip was shown to suppress separation bubble and mitigate internal gap loss. In this study, the aerodynamic characteristics of Wells turbine with radiused blade tip were investigated. The numerical analysis was done by solving three-dimensional steady Reynolds-averaged Navier-Stokes equation with k-ω SST turbulence model. The turbine with blade profile NACA 0015 was taken as the reference blade, and the numerical results were validated with the experimental data. Radiused tip blades with different fillet radius were analysed and they showed similar performance. They improved the operating range and peak torque coefficient by 25% and 37% respectively. The fluid dynamics behind the performance augmentation was also analyzed and reported.

On the Theory of the Wells Turbine

1984 ◽  
Vol 106 (3) ◽  
pp. 628-633 ◽  
Author(s):  
L. M. C. Gato ◽  
A. F. de O. Falca˜o
Keyword(s):  
Three Dimensional ◽  
Axial Flow ◽  
Aerodynamic Performance ◽  
Two Dimensional ◽  
Wells Turbine ◽  
Actuator Disk ◽  
Turbine Efficiency ◽  
Axial Velocity Profile ◽  
Profile Losses ◽  
Blade Shape

A theoretical investigation is presented concerning the aerodynamic performance of the Wells turbine, a self-rectifying, axial-flow turbine suitable for energy extraction from a reciprocating air flow. A two-dimensional analysis is developed, and expressions, based on potential flow, are derived for the blade shape maximizing the turbine efficiency. Three-dimensional effects and profile losses are then accounted for by means of an actuator disk theory, which shows that large radial distortions of axial velocity profile can occur, depending on blade shape, with important implications on the extent of the stall-free conditions.

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