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Wave energy has a great potential to solve the unrelenting energy deficiency in Egypt. The present work recommends Wells turbine as a suitable choice for the Egyptian coasts due to its simple and efficient operation under low input air flow. In addition, the possibility of extracting the wave energy from the Egyptian coasts was investigated using the oscillating water system based on real data from the site. To achieve this purpose, two-dimensional numerical models for Wells turbine airfoils, functioning under sinusoidal wave flow conditions, were built. Moreover, the running and starting characteristics under sinusoidal-flow conditions were investigated using a mathematical code. The results were discussed using the first law analysis, in addition to the second law analysis by using the entropy generation minimization method. It was found that the NACA0015 airfoil always gives a global entropy generation rate that is less than other airfoils by approximately −14%, −10.3% and −14.7% for the sinusoidal wave with time periods equal to 4, 6 and 8 s respectively. Moreover, the effects of blade profile, time period and solidity on the output power (kW) value were discussed. [ABSTRACT FROM AUTHOR]

In the past 20 years, the use of wave energy systems has significantly increased, generally depending on the oscillating water column concept. Wells turbine is one of the most efficient oscillating water column technologies. This article provides an updated and a comprehensive account of the state-of-the-art research on Wells turbine. Hence, it draws a roadmap for the contemporary challenges, which may hinder future reliance on such systems in the renewable energy sector. In particular, the article is concerned with the research directions and methodologies, which aim at enhancing the performance and efficiency of Wells turbine. The article also provides a thorough discussion of the use of CFD for performance modeling and design optimization of Wells turbine. It is found that a numerical model using the CFD code can be employed successfully to calculate the performance characteristics of W-T as well as other experimental and analytical methods. The increase of research papers about CFD, especially in the last 5 years, indicates that there is a trend that considerably depends on the CFD method. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Hydrokinetic energy uses the flowing water of the riverine systems to generate electrical power. The technology is used to meet the green energy requirements in remote villages, to provide power for the isolated areas and factories with a small utility scale. The present study aims to conduct an analysis of the Egyptian riverine systems for remote areas. Numerical analysis is applied using the URANS model. Verification and validation had been implemented with the proper boundary condition. Five ducted airfoils have been simulated around the hybrid Savonius-Darrieus current turbine as an augmentation technique. The ducted airfoils are NACA-0012, NACA-0015, NACA-0018, NACA-0021, and NACA-0024. The study concluded that the optimal ducted airfoil is the NACA-0015. The hybrid turbine had an average power coefficient of 0.114. Also, the first and the second laws of efficiencies were revealed, for the NACA-0015, of 64.9% and 83.4% respectively. • Five ducted airfoils have been investigated around Savonius-Darrieus current turbine. • The model applied the Egyptian riverine systems boundary conditions. • The optimal ducted airfoil was the NACA-0015. • The average power coefficient for the turbine with optimal ducted airfoil was 0.114. • The first and the second laws of efficiencies were 64.9% and 83.4% respectively. [ABSTRACT FROM AUTHOR]

Micro hydrokinetic energy scheme presents an attractive, environmentally-friendly and efficient electric generation in rural, remote and hilly areas. However, this scheme is yet to be fully discovered, as researchers are still searching for solutions for the main problems of low velocity of current in the open flow channels and low efficiency of hydrokinetic turbines. This research proposes a novel system configuration to capture as much kinetic energy as possible from stream water current. This system, known as bidirectional diffuser augmented (BDA) channel, functions by utilizing dual directed nozzles in the flow and is surrounded by dual cross flow/Banki turbines. It is also important to obtain the efficient design parameters of the turbines to use in the current configuration. The appropriate angle is important in order to guide the flow to touch the blades more perpendicularly to capture as much torque and power as possible. Hence, experimental and numerical investigations have been carried out in this research paper to study the performance characteristics of the CFT configuration applied in BDA system and investigate the effects of blades' inlet and outlet angles of CFT runners on the internal flow characteristics and efficiency. In this study, four different runners with various inlet and outlet angles of two CFT have been investigated. The CFD results have been validated with the experimental work and proven acceptable with flow pattern and performance characteristics. The results of the current study conclude that the maximum power coefficients (Cp) of 0.612 and 0.473 for lower and upper turbines are recorded for best runner angles of Case 3. [ABSTRACT FROM AUTHOR]