High efficiency design of an impulse turbine used in oscillating water column to harvest wave energy

Badhurshah, Rameez; Dudhgaonkar, Prasad; Jalihal, Purnima; Samad, Abdus

doi:10.1016/j.renene.2018.01.028

Cited by 45 publications

(14 citation statements)

References 26 publications

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“…GVs along with GV angle and profile. [28] 24% efficiency enhancement for the entire flow range Surrogate-based optimization Circular -elliptical All of the improvements were good news for the device efficiency. However, none of the authors reported how much energy can be extracted from the ocean breaking wave.…”

Section: Number Of Blades Andmentioning

confidence: 97%

Turbine Characteristics of Wave Energy Conversion Device for Extraction Power Using Breaking Waves

et al. 2020

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A new type of wave energy converter which harnesses electricity from onshore breaking waves has been studied at Okinawa Institute of Science and Technology Graduate University (OIST) since 2014. This concept has been demonstrated at a coral beach on the Maldives since 2018. Wave energy conversion is possible when waves approaching the shore steepen due to decreased water depth resulting in wave breaks near the surface. A steepened wave reaches the critical velocity of 4~6 m/sec shoreward before it breaks. A rotating blade takes advantage of this breaking phenomenon to convert the wave energy into electricity. The work presented here includes an experimental and numerical investigation of a prototype model of the wave energy converter. The turbine having five blades of variable chord lengths, twist angles, and constant thickness profile from hub to tip was simulated under similar flow as well as testing conditions, to predict the turbine performance. A commercial computational fluid dynamic tool SolidWorks Flow Simulation 2018 was used for the simulations at various rotation speeds with a uniform inlet velocity. The modified k-ε with a two-scale wall function turbulence closure model was selected. The validation performed for different test cases showed that the present computational results match in good agreement with the experimental results. Additionally, details performance of the turbine running, and generator characteristics have been reported in this paper.

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Section: Number Of Blades Andmentioning

confidence: 97%

Turbine Characteristics of Wave Energy Conversion Device for Extraction Power Using Breaking Waves

et al. 2020

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“…Many analyses of the aerodynamics were performed by applying analytical or CFD models and with laboratory and real field experiments. Generally, the duct comprising the turbine was considered for the optimization of the secondary converter itself and the airflow conditions at the turbine inlet were applied based on conventional literature results [39]. In order to further investigate the airflow field, the motion of the air volume in the system chamber was in some cases modeled with a sinusoidal function [40].…”

Section: Owc Chamber and Impulse Turbine Overviewmentioning

confidence: 99%

“…In 2017, Ezhilsabareesh et al proposed a shape optimization procedure based on CFD and a multiple-surrogate algorithm with a multi-objective function [46]. In 2018, Badhurshah et al performed an optimization procedure to determine the number of rotor blades and guide vanes, guide vane angles, and guide vane profile to maximize the turbine efficiency [39]. In 2020, Ciappi et al developed an analytical model that couples the hydrodynamics, thermodynamics, and aerodynamics of the chamber with the aerodynamics of the air turbine; the operating curves and the performance of two OWC systems embedding a Wells and an impulse turbine were investigated and compared [47].…”

Section: Owc Chamber and Impulse Turbine Overviewmentioning

confidence: 99%

Wave-to-Wire Model of an Oscillating-Water-Column Wave Energy Converter and Its Application to Mediterranean Energy Hot-Spots

et al. 2020

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Oscillating water column (OWC) systems are among the most credited solutions for an effective conversion of the notable energy potential conveyed by sea waves. Despite a renewed interest, however, they are often still at a demonstration phase and additional research is required to reach industrial maturity. Within this framework, this study provides a wave-to-wire model for OWC systems based on an impulse air turbine. The model performs a comprehensive simulation of the system to estimate the attendant electric energy production for a specific sea state, based on analytical models of the primary (fixed chamber) and secondary (air turbine) converters coupled with the tertiary converter (electric generator). A rigid piston model is proposed to solve the hydrodynamics, thermodynamics, and hydrodynamics of the chamber, in a coupled fashion with the impulse turbine aerodynamics. This is solved with a novel method by considering the cascades as sets of blades, each one consisting of a finite number of airfoils stacked in the radial direction. The model was applied for two Mediterranean sites located in Tuscany and Sardinia (Italy), which were selected to define the optimal geometry of the turbine for a specified chamber. For each system, the developed analytical wave-to-wire model was applied to calculate the performance parameters and the annual energy production in environmental conditions typical of the Mediterranean Sea. The selected impulse turbines are able to convert 13.69 and 39.36 MWh/year, with an efficiency of 4.95% and 4.76%, respectively, thus proving the interesting prospects of the technology.

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“…Nevertheless, in the last years due to the increase of computational capabilities some effects have been analyzed also numerical with CFD techniques. For example, CFD techniques combined with hybrid genetic algorithms methods have been recently used to optimized the design of the runner in an automatic way (see the work of Badhurshah et al [19,20]). Liu et al [21] validates the capabilities of CFD techniques to predict the transient response of the turbine by comparing its results with the experimental results of Setoguchi [5].…”

Section: Introductionmentioning

confidence: 99%

Numerical Analysis of the Influence of Design Parameters on the Efficiency of an OWC Axial Impulse Turbine for Wave Energy Conversion

2019

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Oscillating water column (OWC) axial impulse turbines permit the conversion of wave energy into electrical power. Unlike other hydropower units with a mature and well established technology, such turbines have been recently developed, there are still few prototypes operating and therefore there is a large space for optimizing its design. Many recent studies focus on the improvement of the efficiency and transient characteristics by means of experimentation and also simulation techniques. In the present paper we use a 3D numerical simulation model (computational fluid dynamics model with ANSYS-Fluent 18) to analyze the influence of different geometrical parameters on the efficiency of the turbine, which have been less discussed yet. A reference configuration case has been used to validate our simulation model by comparing it with previous experimental results. Then, parametric variations in the guide vane number and type, gaps between the rotating and stationary part and hub to tip ratio have been introduced in the model to discuss the influence of these effects. It is found that some of these parameters have an important influence on the efficiency of the turbine and therefore, the results presented in this paper can help to optimize future designs of OWC impulse turbines.

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High efficiency design of an impulse turbine used in oscillating water column to harvest wave energy

Cited by 45 publications

References 26 publications

Turbine Characteristics of Wave Energy Conversion Device for Extraction Power Using Breaking Waves

Turbine Characteristics of Wave Energy Conversion Device for Extraction Power Using Breaking Waves

Wave-to-Wire Model of an Oscillating-Water-Column Wave Energy Converter and Its Application to Mediterranean Energy Hot-Spots

Numerical Analysis of the Influence of Design Parameters on the Efficiency of an OWC Axial Impulse Turbine for Wave Energy Conversion

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