Performance Analysis of Multi-Sectional Cycloidal Hydrokinetic Turbines

2021 ◽  
Author(s):  
Ang Li ◽  
Yijie Wang ◽  
Jun Chen ◽  
Greg Jensen ◽  
Haiyan Zhang
Keyword(s):  
Fluid Dynamic ◽  
Power Coefficient ◽  
Cfd Simulations ◽  
Hydrokinetic Turbines ◽  
Turbine Efficiency ◽  
Reliable Source ◽  
Sliding Interfaces ◽  
Water Turbine ◽  
Unsteady Rans ◽  
The One

Abstract Hydrokinetic power is the most efficient and reliable source of renewable energy and it has been utilized to produce power for centuries. The cycloidal water turbine is a subset of the H-bar type Darrieus turbines that are designed to actively controls the pitch angle of blades to improve turbine efficiency. However, the traditional cycloidal turbine has some shortcomings. For example, the torque and power coefficient vary significantly as the turbine rotates, which means the produced power is not uniform in one revolution. The associated hydrodynamic load will lead to fatigue of the turbine structure that will shorten the turbine lifespan. To solve this problem, a concept of the multi-sectional cycloidal water turbine is proposed. In the present study, computational fluid dynamic (CFD) simulations are applied to investigate the performance of the multi-sectional cycloidal turbine. A cycloidal turbine with three identical sections is designed. Each section consists of three blades and NACA0021 is chosen as the hydrofoil. Structured mesh with sliding interfaces is generated and arbitrary Mesh Interface (AMI) technique is employed. Unsteady RANS simulations with SST k–ω model are conducted to compute the flow field and torque generated by the turbine, and then power coefficient is computed. The results demonstrates that the three-section turbine has uniform performance in one revolution. At the design condition, the power coefficients of the one-section turbine and the three-section turbine are similar; when the TSR is much larger or less than the desired value, the three-section turbine has better performance.

Unsteady Computational Fluid Dynamic Analysis of the Behavior of Guide Vane Trailing‐Edge Injection and Its Effects on Downstream Rotor Performance in a Francis Hydroturbine

2015 ◽  
Vol 137 (8) ◽  
Author(s):  
Bryan J. Lewis ◽  
John M. Cimbala
Keyword(s):  
Guide Vane ◽  
Flow Direction ◽  
Fluid Dynamic ◽  
Water Injection ◽  
Cfd Simulations ◽  
Trailing Edge ◽  
Computational Fluid Dynamic Analysis ◽  
Flow Angle ◽  
Turbine Efficiency ◽  
Francis Hydroturbine

A unique guide vane design, which includes trailing-edge jets, is presented for a mixed-flow Francis hydroturbine. The water injection causes a change in bulk flow direction at the inlet of the rotor. When properly tuned, altering the flow angle results in a significant improvement in turbine efficiency during off-design operation. Unsteady CFD simulations show nearly 1% improvement in overall turbine efficiency with the use of injection. This revolutionary concept also has the ability to reduce the intensity of the rotor–stator interactions (RSI) by compensating for the momentum deficit of the wicket gate wakes. This technology may be equally applied to other turbomachinery devices with problematic rotor–stator flow misalignments.

scholarly journals Numerical study of savonius water turbine performance by adding deflector to advancing blade side

2018 ◽  
Author(s):  
Priyo Agus Setiawan ◽  
Anda Iviana Juniani ◽  
Adi Wirawan Husodo
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Numerical Study ◽  
Renewable Energy Sources ◽  
Power Coefficient ◽  
Turbine Performance ◽  
Water Turbine ◽  
Unsteady Rans ◽  
Deflector Plate ◽  
Coarse To Fine

As one of the best renewable energy sources, hydropower becomes more predictable sourcecompared to wind energy and Savonius which its performance does not contingent to fluid flowdirection. In this present, computational Fluid Dynamics acomplished by Finite Volume Methodand unsteady RANS equation were applied to analyze the numerical simulation. The presentstudy investigated the performance of Savonius Turbine by adding deflector plate installed toadvancing blade side at 5, 10, 15, 30 and 45 of deflector angles in the direction of the fluid flow.The viscous turbulence model used realizable k-epsilon (RKE) and its descritization usedsecond order upwind. The type of mesh was made from coarse to fine meshing with 8 (eight)types of meshing and the grid independency of the numerical simulation had been validated bythe publish experimental data at TSR of 1,078. Grid independency occured at meshing G withthe error lower than 5 % compared to published experimental data. The result of this studyshows that the performance of Savonius turbine increased by adding deflector in advancingblade side with the maximum torque and power coefficient at 30 of deflector angle.

scholarly journals Unsteady RANS CFD Simulations of Sailboat’s Hull and Comparison with Full-Scale Test

2020 ◽  
Vol 8 (6) ◽  
pp. 394 ◽  
Author(s):  
Pietro Casalone ◽  
Oronzo Dell’Edera ◽  
Beatrice Fenu ◽  
Giuseppe Giorgi ◽  
Sergej Antonello Sirigu ◽  
...  
Keyword(s):  
Fluid Dynamic ◽  
Full Scale ◽  
Navier Stokes ◽  
Hydrodynamic Resistance ◽  
Cfd Simulations ◽  
Unsteady Rans ◽  
Scale Test ◽  
Full Scale Tests ◽  
Substitution Procedure ◽  
Experimental Fluid

The hydrodynamic investigation of a hull’s performance is a key aspect when designing a new prototype, especially when it comes to a competitive/racing environment. This paper purports to perform a fully nonlinear unsteady Reynolds Averaged Navier-Stokes (RANS) simulation to predict the motion and hydrodynamic resistance of a sailboat, thus creating a reliable tool for designing a new hull or refining the design of an existing one. A comprehensive range of speeds is explored, and results are validated with hydrodynamic full-scale tests, conducted in the towing tank facility at University of Naples Federico II, Italy. In particular, this work deals with numerical ventilation, which is a typical issue occurring when modeling a hull; a simple and effective solution is here proposed and investigated, based on the phase-interaction substitution procedure. Results of the computational fluid dynamic (CFD) campaign agree with the experimental fluid dynamic (EFD) within a 2% margin.

Revolutionary Geometries of Mobile Hydrokinetic Turbines for Wind Energy Applications

2015 ◽  
Author(s):  
Kiran Siddappaji ◽  
Mark G. Turner
Keyword(s):  
Wind Energy ◽  
Fluid Dynamic ◽  
Power Coefficient ◽  
Maximum Efficiency ◽  
Power Requirement ◽  
Energy Applications ◽  
Hydrokinetic Turbines ◽  
Analysis System ◽  
Lift And Drag ◽  
Blade Geometry

An abundant source of renewable energy is feasible by harnessing the kinetic energy of moving water using hydrokinetic turbines. The knowledge of wind turbine design, turbomachinery and fluid dynamic principles of incompressible flow can be applied to design traditional and novel geometries of mobile hydrokinetic turbines. A preliminary design is created using the Blade Element Momentum Theory (BEMT) which includes the Prandtl’s correction for tip losses and model corrections. The axial and angular induction factors are calculated iteratively taking into account the coefficient of lift and drag at a certain angle of attack for specific airfoils. Although BEMT does not account for the tip vortices and radial flow induced by the rotation, it provides a good initial geometry. The blade geometry can then be parametrically modified using an in-house 3-D blade geometry generator (3DBGB), and can be analyzed further using a 3-D CFD analysis system. Different configurations such as unshrouded single row, unshrouded counter rotating and shrouded nozzle-rotor-OGV can be explored based on a suitable power requirement. The shrouded design uses a traditional axial turbomachinery approach using 1-D meanline and axisymmetric design-analysis tools (T-AXI suite). Novel geometries with solidity varying spanwise can also be explored to take advantage of the flow across the turbine. A design and analysis system for hydrokinetic turbines is demonstrated. The system is linked to an optimizer to obtain blade shapes with maximum efficiency. A counter rotating design is explored and an optimum design with increased efficiency is obtained. A comparative study of the axial gap between the rotors in a counter rotating system is also presented to show its effect on the power coefficient. The turbine blade designs presented will revolutionize wind energy harness technology.

CFD Simulations of Under Water Turbine in Gulf Stream Using RANS Method

2010 ◽  
Author(s):  
Chaouki Ghenai ◽  
Ben Oliver
Keyword(s):  
Gulf Stream ◽  
Numerical Study ◽  
Turbine Blades ◽  
Three Dimensional ◽  
Power Coefficient ◽  
Total Power ◽  
Cfd Simulations ◽  
Local Flow ◽  
Water Turbine ◽  
Volume Method

The principal objective of this numerical study is to investigate the hydrodynamic behavior of horizontal axis underwater turbine in the Gulf Stream. The CFD analysis provides detailed information about the local flow and the performance of the underwater turbine under varying flow conditions. Three dimensional simulations were performed using a 5.6 meter diameter turbine with 3 blades. The finite volume method was used to solve the equations of conservation of mass and momentum and turbulence (k-ε equations). The flow field, turbulence, pressure distribution on the turbine blades and turbine power were obtained for a range of water speed (1–6 m/s) and rotation speed of turbine (1–10 rad/s). The z-velocity profiles behind the turbine were used to calculate the induction factor a, the power coefficient Cp and the total power P from the turbine. The results show a turbine power coefficient of 33% to 37.5% with an induction factors between 0.10 and 0.12.

Modular Turbulence Modelling Applied to an Engine Intake

2013 ◽  
Author(s):  
Ugochukwu R. Oriji ◽  
Paul G. Tucker
Keyword(s):  
Surface Roughness ◽  
Richardson Number ◽  
Eddy Viscosity ◽  
Fluid Dynamic ◽  
Test Cases ◽  
Laminar Separation ◽  
Streamline Curvature ◽  
Flow Features ◽  
Unsteady Rans ◽  
The One

The one equation Spalart Allamaras (SA) turbulence model in an extended modular form is employed for the prediction of cross wind flow around the lip of a 90 degree sector of an intake with and without surface roughness. The flow features around the lip are complex. There exists a region of high streamline curvature. For this the Richardson number would suggest complete degeneration to laminar flow. Also there are regions of high favourable pressure gradient (FPG) sufficient to laminarize a turbulent boundary layer (BL). This is all terminated by a shock and followed by a laminar separation. Under these severe conditions, the SA model is insensitive to capturing the effects of laminarization and the reenergization of eddy viscosity which promotes the momentum transfer and correct reattachment prior to the fan face. Through distinct modules, the SA model has been modified to account for the effect of laminarization and separation induced transition. The SA modules have been implemented in Rolls-Royce HYDRA Computational Fluid Dynamic (CFD) solver. They have been validated over a number of experimental test cases involving laminarization and also surface roughness. The validated modules are finally applied in unsteady RANS mode to flow around an engine intake and comparisons made with measurements. Encouraging agreement is found and hence advances made towards a more reliable intake design framework.

ANALISIS VARIASI JUMLAH SUDU TURBIN BERPENAMPANG PELAT DATAR PADA TURBIN AIR ALIRAN VORTEX DENGAN TIPE SALURAN MASUK INVOLUTE

2020 ◽  
Vol 7 (2) ◽  
pp. 72-78
Author(s):  
Adnan Al Farisi ◽  
Yopi Handoyo ◽  
Taufiqur Rokhman
Keyword(s):  
Power Plant ◽  
Alternative Energy ◽  
Vortex Flow ◽  
Experimental Methods ◽  
Turbine Efficiency ◽  
A Value ◽  
Current Voltage ◽  
Materials Research ◽  
The One ◽  
Flow Vortex

The One of alternative energy that is environmentally friendly is by untilize water energy and turn it into a Microhydro power plant. Microhydro power plant usually made from utilize the waterfall with the head fell. While utilization for streams with a head small drop is not optimal yet. This is a reference to doing research on harnessing the flow of a river that has a value of head low between 0.7 m – 1.4 m with turning it into a Vortex flow (vortex). The purpose of this research is to know  the effect variation number of blade on power and efficiency in the vortex turbine. This research uses experimental methods to find current, voltage, torque and rpm using a reading instrument. The materials research vortex turbine used 6 blade, 8 blade and 10 blade with flat plate. The result showed the highest efficiency is 29,93 % with produce turbine power is 19,58 W, generated on turbine with variation 10 blade with load 3,315 kg and the capacity of water 10,14 l/s. Followed with an efficiency 24,17% and produce turbine power is 15,81 W, generated on turbine with the variation 8 blade with load 3,315 kg and the capacity of water is 10,14 l/s. The the lowest turbine efficiency 22,32% with produce tuebine power 14,60 W, generated on turbine with the variation 6 blade with load 3,315 kg, the capacity of water is 10,14 l/s.

scholarly journals Two-phase CFD simulation of the monodyspersed suspension hydraulic behaviour in the tank apparatus from a circulatory pipe

2008 ◽  
Vol 10 (1) ◽  
pp. 22-27 ◽  
Author(s):  
Roch Plewik ◽  
Piotr Synowiec ◽  
Janusz Wójcik
Keyword(s):  
Cfd Simulation ◽  
Fluidised Bed ◽  
Cfd Simulations ◽  
Two Phase ◽  
Hydraulic Behaviour ◽  
Hydraulic Conditions ◽  
The One ◽  
Cfd Method ◽  
Multi Phase ◽  
The Ideal

Two-phase CFD simulation of the monodyspersed suspension hydraulic behaviour in the tank apparatus from a circulatory pipe The hydrodynamics in fluidized-bed crystallizers is studied by CFD method. The simulations were performed by a commercial packet of computational fluid dynamics Fluent 6.x. For the one-phase modelling (15), a standard k-ε model was applied. In the case of the two-phase flows the Eulerian multi-phase model with a standard k-ε method, aided by the k-ε dispersed model for viscosity, has been used respectively. The collected data put a new light on the suspension flow behaviour in the annular zone of the fluidised bed crystallizer. From the presented here CFD simulations, it clearly issues that the real hydraulic conditions in the fluidised bed crystallizers are far from the ideal ones.

Innovative Variable Turbine Concept for Turbochargers

2011 ◽  
Author(s):  
Elias Chebli ◽  
Michael Casey ◽  
Markus Mu¨ller ◽  
Siegfried Sumser ◽  
Gernot Hertweck ◽  
...  
Keyword(s):  
Aerodynamic Performance ◽  
Cfd Simulations ◽  
Flow Variability ◽  
Variable Turbine Geometry ◽  
Turbine Efficiency ◽  
New Concepts ◽  
Specific Speed ◽  
Turbine Impeller ◽  
Flow Cross ◽  
Wide Operating

New concepts for the optimisation of supercharging systems have been analysed to improve fuel consumption, emissions and transient diesel engine response. In addition to the conventional VTG (Variable Turbine Geometry) where the variability takes place upstream of the turbine impeller, a new innovative variable turbine geometry called VOT (Variable Outlet Turbine) is investigated in this paper where the variability takes place at impeller exit. The flow variability is achieved by variation of the flow cross-section at the turbine outlet using an axial displacement of a sliding sleeve over the exducer and provides a simple solution for flow variability. The flow field of the VOT is calculated by means of steady state 3D-CFD simulations to predict the aerodynamic performance as well as to analyse the loss mechanisms. The VOT design is optimised by finding a good balance between clearance and outlet losses to improve the turbine efficiency. Furthermore, experimental results of the VOT are presented and compared to a turbine equipped with a waste gate (WG) that verify the efficiency advantage of the VOT. In general, it is found that the use of the VOT at high specific speed is important to reduce the outlet losses and to improve the turbine efficiency over a wide operating range.

Performance study of twisted Darrieus hydrokinetic turbine with novel blade design

2021 ◽  
pp. 1-37
Author(s):  
Mabrouk Mosbahi ◽  
Mouna Derbel ◽  
Mariem Lajnef ◽  
Bouzid Mosbahi ◽  
Zied Driss ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Maximum Power ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Small Scale ◽  
Performance Study ◽  
Hydrokinetic Turbine ◽  
Blade Shape ◽  
Water Turbine ◽  
Water Canals

Abstract Twisted Darrieus water turbine is receiving growing attentiveness for small-scale hydropower generation. Accordingly, the need for raised water energy conversion incentivizes researchers to focalise on the blade shape optimization of twisted Darrieus turbine. In view of this, an experimental analysis has been performed to appraise the efficiency of a spiral Darrieus water rotor in the present work. To better the performance parameters of the studied water rotor with twisted blades, three novel blade shapes, namely U-shaped blade, V-shaped blade and W-shaped blade, have been numerically tested using a computational fluid dynamics three-dimensional numerical model. Maximum power coefficient of Darrieus rotor reaches 0.17 at 0.63 tip-speed ratio using twisted blades. Using V-shaped blades, maximum power coefficient has been risen up to 0.185. The current study could be practically applied to provide more effective employment of twisted Darrieus turbines and to improve the generated power from flowing water such as river streams, tidal currents, or other man made water canals.

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