Passive Pitch Control of Horizontal Axis Marine Hydrokinetic Turbine Blades

2014 ◽  
Author(s):  
Michael R. Motley ◽  
Ramona B. Barber
Keyword(s):  
Alternative Energy ◽  
Turbine Blades ◽  
Operating Conditions ◽  
Horizontal Axis ◽  
Pitch Control ◽  
Fluid Forces ◽  
Hydrokinetic Turbines ◽  
Energy Technologies ◽  
Hydrokinetic Turbine ◽  
Marine Hydrokinetic

As the need for clean and renewable energy becomes greater, alternative energy technologies are becoming more and more prevalent. To that end, there has been a recent increase in research on marine hydrokinetic turbines to assess their potential as a reliable source of energy production and to expedite their implementation. These turbines are typically constructed from fiber reinforced composites and are subject to large, dynamic fluid forces. One of the benefits of composite materials is that the bend-twist deformation behavior can be hydroelastically tailored such that the blades are able to passively change their pitch to adapt to the surrounding flow, creating a nearly instantaneous control mechanism that can improve system performance over the expected range of operating conditions. These improvements include increasing energy capture, reducing instabilities, and improving structural performance. Practical constraints, however, lead to limitations in the scope of these performance enhancements and create tradeoffs between various benefits that can be achieved. This paper presents a numerical investigation into the capability of passive pitch control and combined active/passive pitch control to modify the performance of horizontal axis marine turbines with proper consideration of practical restrictions.

Adaptive Composites for Load Control in Marine Turbine Blades

2017 ◽  
Author(s):  
Ramona B. Barber ◽  
Craig S. Hill ◽  
Pavel F. Babuska ◽  
Alberto Aliseda ◽  
Richard Wiebe ◽  
...  
Keyword(s):  
Composite Structures ◽  
Turbine Blades ◽  
Frp Composites ◽  
Hydrokinetic Turbines ◽  
Hydrokinetic Turbine ◽  
Marine Hydrokinetic ◽  
Strength And Stiffness ◽  
Adaptive Composites ◽  
Composite Blades ◽  
Adaptive Composite

Marine hydrokinetic turbines typically operate in harsh, strongly dynamic conditions. All components of the turbine system must be extremely robust and able to withstand large and constantly varying loads; the long and relatively slender blades of marine turbines are especially vulnerable. Because of this, modern marine turbine blades are increasingly constructed from fiber reinforced polymer (FRP) composites. Composite materials provide superior strength- and stiffness-to-weight ratios and improved fatigue and corrosion resistance compared to traditional metallic alloys. Additionally, it is possible to tailor the anisotropic properties of FRP composites to create an adaptive pitch mechanism that will adjust the load on the turbine in order to improve system performance, especially in off-design or varying flow conditions. In this work, qualitative fundamentals of composite structures are discussed with regards to the design of experimental scale adaptive pitch blades. The load-deformation relationship of flume-scale adaptive composite blades are characterized experimentally under static loading conditions, and dynamic loading profiles during flume testing are reported. Two sets of adaptive composite blades are compared to neutral pitch composite and rigid aluminum designs. Experimental results show significant load adjustments induced through passive pitch adaptation, suggesting that adaptive pitch composite blades could be a valuable addition to marine hydrokinetic turbine technology.

Influence of Blade Solidity on Marine Hydrokinetic Turbines

2012 ◽  
Author(s):  
Michael Jonson ◽  
John Fahnline ◽  
Erick Johnson ◽  
Matthew Barone ◽  
Arnold Fontaine
Keyword(s):  
Marine Ecosystem ◽  
Turbine Blades ◽  
Electrical Power ◽  
Well Being ◽  
Wind Turbine Blades ◽  
Blade Vibration ◽  
Radiated Noise ◽  
Hydrokinetic Turbines ◽  
Horizontal Axis Wind Turbines ◽  
Marine Hydrokinetic

Marine hydrokinetic (MHK) devices are currently being considered for the generation of electrical power in marine tidal regions. Turbulence generated in the boundary layers of these channels interacts with a turbine to excite the blades into low-to mid-frequency vibration. Additionally, the self-generated turbulent boundary layer on the turbine blade excites its trailing edge into vibration. Both of these hydrodynamic sources generate radiated noise. Being installed in a marine ecosystem, the noise generated by these MHK devices may affect the fish and marine mammal well-being. Since this MHK technology is relatively new, much of the design practice follows that from conventional horizontal axis wind turbines. In contrast to other underwater turbomachines like conventional merchant ships that have solid blades, wind turbine blades are made of hollow fiberglass composites. This paper systematically investigates the contrast of this design detail on the blade vibration and radiated noise for a particular MHK turbine design.

Passive control of marine hydrokinetic turbine blades

2014 ◽  
Vol 110 ◽  
pp. 133-139 ◽  
Author(s):  
Michael R. Motley ◽  
Ramona B. Barber
Keyword(s):  
Passive Control ◽  
Turbine Blades ◽  
Hydrokinetic Turbine ◽  
Marine Hydrokinetic

Proton Exchange Membrane Fuel Cell Emulator Using PI Controlled Buck Converter

2017 ◽  
Vol 8 (1) ◽  
pp. 462 ◽  
Author(s):  
Himadry Shekhar Das ◽  
Chee Wei Tan ◽  
AHM Yatim ◽  
Nik Din Bin Muhamad
Keyword(s):  
Fuel Cell ◽  
Alternative Energy ◽  
Proton Exchange Membrane ◽  
Buck Converter ◽  
Proton Exchange ◽  
Operating Conditions ◽  
Load Current ◽  
Energy Technologies ◽  
Exchange Membrane ◽  
Electrochemical Model

Alternative energy technologies are being popular for power generation applications nowadays. Among others, Fuel cell (FC) technology is quite popular. However, the FC unit is costly and vulnerable to any disturbances in input parameters. Thus, to perform research and experimentation, Fuel cell emulators (FCE) can be useful. FCEs can replicate actual FC behavior in different operating conditions. Thus, by using it the application area can be determined. In this study, a FCE system is modelled using MATLAB/Simulink®. The FCE system consists of a buck DC-DC converter and a proportional integral (PI) based controller incorporating an electrochemical model of proton exchange membrane fuel cell (PEMFC). The PEMFC model is used to generate reference voltage of the controller which takes the load current as a requirement. The characteristics are compared with Ballard Mark V 5kW PEMFC stack specifications obtained from the datasheet. The results show that the FCE system is a suitable replacement of real PEMFC stack and can be used for research and development purpose.

AN APPROACH FOR THE OPTIMUM HYDRODYNAMIC DESIGN OF HYDROKINETIC TURBINE BLADES

2015 ◽  
Vol 14 (2) ◽  
pp. 43 ◽  
Author(s):  
L. D. Shinomiya ◽  
J. R. P. Vaz ◽  
A. L. A. Mesquita ◽  
T. F. De Oliveira ◽  
A. C. P. Brasil Jr ◽  
...  
Keyword(s):  
Twist Angle ◽  
Turbine Blades ◽  
Thrust Coefficient ◽  
Blade Element Theory ◽  
Hydrokinetic Turbines ◽  
Cavitation Effect ◽  
Hydrokinetic Turbine ◽  
Blade Section ◽  
And Performance ◽  
Rotor Shape

This work aims to develop a simple and efficient mathematical model applied to optimization of horizontal-axis hydrokinetic turbine blades considering the cavitation effect. The approach uses the pressure minimum coefficient as a criterion for the cavitation limit on the flow around the hydrokinetic blades. The methodology corrects the chord and twist angle at each blade section by a modification on the local thrust coefficient in order to takes into account the cavitation on the rotor shape. The optimization is based on the Blade Element Theory (BET), which is a well known method applied to design and performance analysis of wind and hydrokinetic turbines, which usually present good agreement with experimental data. The results are compared with data obtained from hydrokinetic turbines designed by the classical Glauert's optimization. The present method yields good behavior, and can be used as an alternative tool in efficient hydrokinetic turbine designs.

scholarly journals Investigating the Influence of the Added Mass Effect to Marine Hydrokinetic Horizontal-Axis Turbines Using a General Dynamic Wake Wind Turbine Code

2012 ◽  
Vol 46 (4) ◽  
pp. 71-78 ◽  
Author(s):  
David C. Maniaci ◽  
Ye Li
Keyword(s):  
Wind Turbine ◽  
Unsteady Aerodynamics ◽  
Mass Effect ◽  
Added Mass ◽  
Horizontal Axis ◽  
Mass Model ◽  
Horizontal Axis Wind Turbine ◽  
Flow Acceleration ◽  
Hydrokinetic Turbines ◽  
Marine Hydrokinetic

AbstractThis paper describes a recent study to investigate the applicability of a horizontal-axis wind turbine structural dynamics and unsteady aerodynamics analysis program (FAST and AeroDyn, respectively) for modeling the forces on marine hydrokinetic turbines. This paper summarizes the added mass model that has been added to AeroDyn. The added mass model only includes flow acceleration perpendicular to the rotor disc and ignores added mass forces caused by blade deflection. A model of the National Renewable Energy Laboratory’s Unsteady Aerodynamics Experiment Phase VI wind turbine was analyzed using FAST and AeroDyn with seawater conditions and the new added mass model. The results of this analysis exhibited a 3.6% change in thrust for a rapid pitch case and a slight change in amplitude and phase of thrust for a case with 30° of yaw.

scholarly journals Analytic Characterization of the Wake Behind In-Stream Hydrokinetic Turbines

2017 ◽  
Vol 51 (6) ◽  
pp. 58-71 ◽  
Author(s):  
Parakram Pyakurel ◽  
James H. VanZwieten ◽  
Tian Wenlong ◽  
Palaniswamy Ananthakrishnan
Keyword(s):  
Experimental Studies ◽  
Operating Conditions ◽  
Radial Dependence ◽  
Data Sets ◽  
Hydrokinetic Turbines ◽  
Hydrokinetic Turbine ◽  
Wake Model ◽  
Ambient Turbulence ◽  
Empirical Coefficients

AbstractAnalytical algorithms developed and optimized for quantifying the wake behind in-stream hydrokinetic turbines are presented. These algorithms are based on wake expressions originally developed for wind turbines. Unlike previous related studies, the optimization of empirical coefficients contained in these algorithms is conducted using centerline velocity data from multiple published experimental studies of the wake velocities behind in-stream hydrokinetic turbine models or porous disks and not using computational fluid dynamics. Empirical coefficients are first individually optimized based on each set of experimental data, and then empirically based coefficient expressions are created using all of the data sets collectively, such that they are functions of ambient turbulence intensity. This expands the applicability of the created algorithms to cover the expected range of operating conditions for in-stream hydrokinetic turbines. Wind turbine wake model expressions are also modified to characterize the dependence of wake velocities on radial location from the centerline of in-stream hydrokinetic turbines. Thus, expressions with empirically optimized coefficients for calculating wake velocities behind in-stream hydrokinetic turbines are described in terms of both centerline and radial positions. Wake predictions made using the Larsen model for radial dependence are shown to diverge from experimental measurements near the wake radius defined by the Jensen model, suggesting that this is a good indication of the cutoff point beyond which numerical estimations no longer apply. Results suggest that using a combined Larsen/Ainslie approach or combined Jensen/Ainslie approach for characterizing wake have similar mean errors to using only a Larsen approach.

scholarly journals Design and Optimization of a Multi-Element Hydrofoil for a Horizontal-Axis Hydrokinetic Turbine

Energies ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4679
Author(s):  
Jonathan Aguilar ◽  
Ainhoa Rubio-Clemente ◽  
Laura Velasquez ◽  
Edwin Chica
Keyword(s):  
Lift Coefficient ◽  
Electrical Energy ◽  
Chord Length ◽  
Horizontal Axis ◽  
Low Flow ◽  
Main Element ◽  
Water Current ◽  
Electric Generator ◽  
Hydrokinetic Turbines ◽  
Hydrokinetic Turbine

Hydrokinetic turbines are devices that harness the power from moving water of rivers, canals, and artificial currents without the construction of a dam. The design optimization of the rotor is the most important stage to maximize the power production. The rotor is designed to convert the kinetic energy of the water current into mechanical rotation energy, which is subsequently converted into electrical energy by an electric generator. The rotor blades are critical components that have a large impact on the performance of the turbine. These elements are designed from traditional hydrodynamic profiles (hydrofoils), to directly interact with the water current. Operational effectiveness of the hydrokinetic turbines depends on their performance, which is measured by using the ratio between the lift coefficient (CL) and the drag coefficient (CD) of the selected hydrofoil. High lift forces at low flow rates are required in the design of the blades; therefore, the use of multi-element hydrofoils is commonly regarded as an adequate solution to achieve this goal. In this study, 2D CFD simulations and multi-objective optimization methodology based on surrogate modelling were conducted to design an appropriate multi-element hydrofoil to be used in a horizontal-axis hydrokinetic turbine. The Eppler 420 hydrofoil was utilized for the design of the multi-element hydrofoil composed of a main element and a flap. The multi-element design selected as the optimal one had a gap of 2.825% of the chord length (C1), an overlap of 8.52 %C1, a flap deflection angle (δ) of 19.765°, a flap chord length (C2) of 42.471 %C1, and an angle of attack (α) of –4°.

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