scholarly journals A computational design method for bio-mimicked horizontal axis tidal turbines

2018 ◽  
Vol 36 (2) ◽  
pp. 188-209
Author(s):  
Siddharth Suhas Kulkarni ◽  
Craig Chapman ◽  
Hanifa Shah ◽  
David John Edwards
Keyword(s):  
Turbine Blade ◽  
Turbulence Model ◽  
Design Method ◽  
Lift Coefficient ◽  
Computational Design ◽  
Horizontal Axis ◽  
Power Coefficient ◽  
Content Type ◽  
Tidal Turbines ◽  
Tidal Turbine

Purpose The purpose of this paper is to conduct a comparative analysis between a straight blade (SB) and a curved caudal-fin tidal turbine blade (CB) and to examine the aspects relating to geometry, turbulence modelling, non-dimensional forces lift and power coefficients. Design/methodology/approach The comparison utilises results obtained from a default horizontal axis tidal turbine with turbine models available from the literature. A computational design method was then developed and implemented for “horizontal axis tidal turbine blade”. Computational fluid dynamics (CFD) results for the blade design are presented in terms of lift coefficient distribution at mid-height blades, power coefficients and blade surface pressure distributions. Moving the CB back towards the SB ensures that the total blade height stays constant for all geometries. A 3D mesh independency study of a “straight blade horizontal axis tidal turbine blade” modelled using CFD was carried out. The grid convergence study was produced by employing two turbulence models, the standard k-ε model and shear stress transport (SST) in ANSYS CFX. Three parameters were investigated: mesh resolution, turbulence model, and power coefficient in the initial CFD, analysis. Findings It was found that the mesh resolution and the turbulence model affect the power coefficient results. The power coefficients obtained from the standard k-ε model are 15 to 20 per cent lower than the accuracy of the SST model. Further analysis was performed on both the designed blades using ANSYS CFX and SST turbulence model. The variation in pressure distributions yields to the varying lift coefficient distribution across blade spans. The lift coefficient reached its peak between 0.75 and 0.8 of the blade span where the total lift accelerates with increasing pressure before drastically dropping down at 0.9 onwards due to the escalating rotational velocity of the blades. Originality/value The work presents a computational design methodological approach that is entirely original. While this numerical method has proven to be accurate and robust for many traditional tidal turbines, it has now been verified further for CB tidal turbines.

scholarly journals Computational Fluid Dynamics (CFD) Mesh Independency Study of A Straight Blade Horizontal Axis Tidal Turbine

2016 ◽  
Author(s):  
Siddharth Suhas Kulkarni ◽  
Craig Chapman ◽  
Hanifa Shah
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Turbulence Model ◽  
Horizontal Axis ◽  
Power Coefficient ◽  
Straight Blade ◽  
Mesh Resolution ◽  
Tidal Turbine ◽  
Torque Coefficient ◽  
Computational Fluid Dynamics Cfd

This paper numerically investigates a 3D mesh independency study of a straight blade horizontal axis tidal turbine modelled using Computational Fluid Dynamics (CFD). The solution was produced by employing two turbulence models, the standard k-ε model and Shear Stress Transport (SST) in ANSYS CFX. Three parameters were investigated: mesh resolution, turbulence model, and power coefficient in the initial CFD, analysis. It was found that the mesh resolution and the turbulence model affect the power coefficient results. The power coefficients obtained from the standard k-ε model are 15% to 20% lower than the accuracy of the SST model. It can also be demonstrated that the torque coefficient increases with the increasing Tip Speed Ratio (TSR), but drops drastically after TSR = 5 and k-ε model failing to capture the non-linearity in the torque coefficient with the increasing TSR.

scholarly journals Designing an efficient tidal turbine blade through bio-mimicry: a systematic review

2018 ◽  
Vol 16 (1) ◽  
pp. 101-124 ◽  
Author(s):  
Siddharth Kulkarni ◽  
Craig Chapman ◽  
Hanifa Shah ◽  
Erika Anneli Parn ◽  
David John Edwards
Keyword(s):  
Turbine Blade ◽  
Renewable Energy Sources ◽  
Clean Energy ◽  
Horizontal Axis ◽  
Maximum Efficiency ◽  
Energy Sources ◽  
Caudal Fin ◽  
Content Type ◽  
Tidal Turbine ◽  
Ocean Environment

Purpose This paper aims to conduct a comprehensive literature review in the tidal energy physics, the ocean environment, hydrodynamics of horizontal axis tidal turbines and bio-mimicry. Design/methodology/approach The paper provides an insight of the tidal turbine blade design and need for renewable energy sources to generate electricity through clean energy sources and less CO2 emission. The ocean environment, along with hydrodynamic design principles of a horizontal axis tidal turbine blade, is described, including theoretical maximum efficiency, blade element momentum theory and non-dimensional forces acting on tidal turbine blades. Findings This review gives an overview of fish locomotion identifying the attributes of the swimming like lift-based thrust propulsion, the locomotion driving factors: dorsal fins, caudal fins in propulsion, which enable the fish to be efficient even at low tidal velocities. Originality/value Finally, after understanding the phenomenon of caudal fin propulsion and its relationship with tidal turbine blade hydrodynamics, this review focuses on the implications of bio-mimicking a curved caudal fin to design an efficient horizontal axis tidal turbine.

scholarly journals Design Optimization of a Multi-Megawatt Wind Turbine Blade with the NPU-MWA Airfoil Family

Energies ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 3330 ◽  
Author(s):  
Jianhua Xu ◽  
Zhonghua Han ◽  
Xiaochao Yan ◽  
Wenping Song
Keyword(s):  
Wind Turbine ◽  
Turbine Blade ◽  
Weight Reduction ◽  
Stokes Equations ◽  
Lift Coefficient ◽  
Turbine Blades ◽  
Aerodynamic Performance ◽  
Wind Turbine Blade ◽  
Structural Performance ◽  
Power Coefficient

A new airfoil family, called NPU-MWA (Northwestern Polytechnical University Multi-megawatt Wind-turbine A-series) airfoils, was designed to improve both aerodynamic and structural performance, with the outboard airfoils being designed at high design lift coefficient and high Reynolds number, and the inboard airfoils being designed as flat-back airfoils. This article aims to design a multi-megawatt wind turbine blade in order to demonstrate the advantages of the NPU-MWA airfoils in improving wind energy capturing and structural weight reduction. The distributions of chord length and twist angle for a 5 MW wind turbine blade are optimized by a Kriging surrogate model-based optimizer, with aerodynamic performance being evaluated by blade element-momentum theory. The Reynolds-averaged Navier–Stokes equations solver was used to validate the improvement in aerodynamic performance. Results show that compared with an existing NREL (National Renewable Energy Laboratory) 5 MW blade, the maximum power coefficient of the optimized NPU 5 MW blade is larger, and the chord lengths at all span-wise sections are dramatically smaller, resulting in a significant structural weight reduction (9%). It is shown that the NPU-MWA airfoils feature excellent aerodynamic and structural performance for the design of multi-megawatt wind turbine blades.

A Simplified Design Method of Horizontal Axis Tidal Energy Turbine Blade

2014 ◽  
Vol 525 ◽  
pp. 240-246
Author(s):  
Xiao Hang Wang ◽  
Li Zhang ◽  
Liang Zhang
Keyword(s):  
Design Method ◽  
Tidal Energy ◽  
Horizontal Axis ◽  
Speed Ratio ◽  
Flow Angle ◽  
Momentum Theory ◽  
Tidal Turbines ◽  
Computational Fluid Dynamics Cfd ◽  
Simulation Results ◽  
Blade Element

Horizontal axis tidal turbines (HATTs) are efficient in converting tidal energy. Improvements in the design of the HATTs require a thorough understanding of the energy conversion process. In this paper, the design of a HATT with two blades is conducted by blade element momentum theory (BEM). In this simplified method, the eddy current induced by the rotors hub and tips were considered while ignoring the blade elements drag items. Based on the assumption of maximum power of blade elements, the distribution of blade elements flow angle and the chord length coefficient along the radius can be assumed to be associated only with the blade elements tip speed ratio (TSR) which is dimensionless. This approach was validated by comparing the simulation results with computational fluid dynamics (CFD). A good qualitative match between the expected value and simulation results was observed, indicating that the design method is feasible and reasonable.

scholarly journals Experimental investigations of winglet effects on blade geometry of small horizontal axis wind turbine rotors

2021 ◽  
Author(s):  
Manoj Kumar Chaudhary ◽  
◽  
S. Prakash ◽  
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Lift Coefficient ◽  
Research Work ◽  
Operating Conditions ◽  
Horizontal Axis ◽  
Power Coefficient ◽  
Experimental Investigations ◽  
Horizontal Axis Wind Turbine ◽  
Blade Geometry

In this research work, the investigation and optimization of small horizontal axis wind turbine blade at low wind speed is pursued. The experimental blades were developed using the 3D printing additive manufacturing technique. The airfoils E210, NACA2412, S1223, SG6043, E216, NACA4415, SD7080, SD7033, S1210 and MAF were tested at the wind speed of 2-6 m/s. The airfoils and optimum blade geometry were investigated with the aid of the Xfoil software at Reynolds number of 100,000. The initial investigation range included tip speed ratios from 3 to 10, solidity from 0.0431 – 0.1181 and angle of attacks from 2o to 20o. Later on these parameters were varied in MATLAB and Xfoil software for optimization and investigation of the power coefficient, lift coefficient, drag coefficient and lift to drag ratio. The cut-in wind speed of the rotors was 2 and 2.5 m/s with the winglet-equipped blades and without winglets. It was found that the E210, SG6043, E216 NACA4415 and MAF airfoil displayed better performance than the NACA 2412, S1223, SD7080, S1210 & SD7003 for the geometry optimized for the operating conditions and manufacturing method described.

Study of horizontal axis tidal turbine performance and investigation on the optimum fixed pitch angle using CFD

2019 ◽  
Vol 30 (1) ◽  
pp. 206-227 ◽  
Author(s):  
Hoseyn A. Amiri ◽  
Rouzbeh Shafaghat ◽  
Rezvan Alamian ◽  
Seyed Mohamad Taheri ◽  
Mostafa Safdari Shadloo
Keyword(s):  
Pitch Angle ◽  
Flow Characteristics ◽  
Horizontal Axis ◽  
Speed Ratio ◽  
Wall Region ◽  
Computational Domain ◽  
Thrust Coefficient ◽  
Content Type ◽  
Tidal Turbine ◽  
Fixed Pitch

Purpose The purpose of this paper is to design, investigate and optimize a horizontal axis tidal turbine (HATT) using computer-aided numerical simulation and computational fluid dynamics (CFD). This is the first step of research and development (R&D) for implementation in the Persian Gulf condition. To do so, suitable locations are reviewed. Then, the optimization is focused on determining the optimum fixed pitch angle (β) of a three-bladed HATT based on the widespread multiple reference frame (MRF) technique to calculate power and thrust coefficients at different operational rotating speeds. Design/methodology/approach To simplify the problem and reducing the computational costs due to cyclic symmetry only one blade, accordingly one-third of the whole computational domain is considered in the modeling. Due to flow’s nature involving rotating, separation and recirculation, a realizable κ-ε turbulence model with standard wall function is selected to capture flow characteristics influenced by the rotor and near the wall region. Simulations are conducted for two free-stream velocities, then compared with their dependencies through the dimensionless tip speed ratio (TSR) parameter. Findings The validation process of the simulations is carried out by the use of AeroDyn BEM code, which has been evaluated by comparing with two experimental data. As results, the highest coefficient of power is achieved at ß = 19.3° at TSR = 4 with the value around 0.41 and 0.816 for thrust coefficient. Furthermore, to comprehend the rotor’s performance and simulation method, flow characteristics due to the rise in angular velocity is discussed in detail. Moreover, the major phenomenon, cavitation occurrence, is also checked at the critical situation where it is found to be safe. Originality/value By comparing and evaluating the results to other HATTs, it implies that the proposed rotor of this study is feasible and proved by CFD evaluation at this step. However, the current rotor is awaiting a justification through experimental assessment.

scholarly journals Structural design and analysis of composite blade for horizontal-axis tidal turbine

2018 ◽  
Vol 25 (6) ◽  
pp. 1075-1083
Author(s):  
Quang Duy Nguyen ◽  
Hoon Cheol Park ◽  
Taesam Kang ◽  
Jin Hwan Ko
Keyword(s):  
Structural Design ◽  
Thickness Distribution ◽  
Beam Theory ◽  
High Strength ◽  
Horizontal Axis ◽  
Power Coefficient ◽  
Speed Ratio ◽  
Composite Blade ◽  
Tidal Turbine ◽  
Twisted Beam

AbstractIn this work, we report on the structural design of a 5-m-long composite blade intended for use in a horizontal-axis tidal turbine. The blade geometry is constructed through an optimization process to obtain the maximum power coefficient at the desired tip speed ratio of 4.5 by applying the blade element-momentum theory (BEMT). The blade is primarily designed using a NACA 63-424 hydrofoil. The blade structure is designed by using the BEMT to compute the loading conditions at various inflow velocities. Two parallel spars were chosen to produce the blade structure grid, and the preliminary lay-up structure of the composite blade was determined according to the thickness distribution identified using the twisted beam theory under the assumption that the two spars plus the upper and lower skins mostly contribute to the flap-wise bending stiffness while withstanding an external load. Then, high-strength unidirectional and double-bias fiber glass/epoxy materials were chosen to fabricate the blade. The final blade structure was then analyzed in ANSYS Workbench using the finite element method. The results show that the blade structure can withstand the applied load with failure indices <0.4.

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