Article
Thermodynamics
Bo Feng, Xiaodong Liu, You Ying, Yulin Si, Dahai Zhang, Peng Qian
Summary: Research shows that in the tandem arrangement of turbines, the downstream turbine's performance significantly degrades but can partially recover with an increase in tandem distance. However, the issue of load fluctuation still persists in tandem configurations and is even more severe than in the upstream turbine.
ENERGY CONVERSION AND MANAGEMENT
(2022)
Article
Thermodynamics
Xiaodong Liu, Bo Feng, Di Liu, Yiming Wang, Haitao Zhao, Yulin Si, Dahai Zhang, Peng Qian
Summary: This study investigated the hydrodynamic performance of a counter-rotating tidal turbine with variable rotor distance and rotation speed, finding that both factors can affect the efficiency and stability of the upstream and downstream rotors. Through experimental validation and numerical simulation, it was concluded that the dual-rotor system achieves the best energy efficiency at a rotor distance of 0.4D.
Article
Engineering, Ocean
Zhi Zhang, Yuquan Zhang, Jisheng Zhang, Yuan Zheng, Wei Zang, Xiangfeng Lin, E. Fernandez-Rodriguez
Summary: The experimental investigation on the influence of increased ambient turbulent intensity (ATI) on the wake of a three bladed tidal turbine showed that slightly increased ATI can accelerate far wake recovery, decrease inhomogeneity and increase the energy utilization of downstream turbine and the degree of wake turbulence anisotropy.
APPLIED OCEAN RESEARCH
(2021)
Article
Engineering, Marine
Lucien Jouenne, Philippe Druault, Jean-Francois Krawczynski, Gregory Germain
Summary: In this study, Particle Image Velocimetry (PIV) measurements are used to investigate turbulent-flow modifications in front of a horizontal axis tidal turbine positioned in a low-disturbance uniform flow. The results show that regardless of the rotational speed, a similar velocity profile is observed, with the uniform flow evolving into a shear flow. The turbine rotational speed mainly affects the axial velocity deficit, while the mean radial velocity component in front of the hub is not sensitive to the rotational speed. However, its amplitude increases near the tip of the blade as the Tip Speed Ratio increases. Additionally, the validity of different analytical induction models is verified using the PIV database, with some discrepancies observed in front of the hub.
Article
Engineering, Marine
Zhen-qi Li, Guang-nian Li, Lin Du, Hai-peng Guo, Wen-xin Yuan
Summary: This study focuses on the key technologies of hydraulic turbine geometric modeling and reconstruction. The blade element momentum theory is adopted to obtain the distribution of the twist angle and chord of the blade, and a parameterized model of the original rotor is established. Further, the artificial neural network and the Genetic Algorithm (GA) are used to optimize the performance of the original blades. According to numerical simulations based on Computational Fluid Dynamics (CFD), the energy conversion efficiency of the optimized rotor is higher than that of the original rotor, with an improvement of up to 8.5% under the considered blade-tip speed ratios, and the thrust coefficient is significantly increased.
Article
Engineering, Marine
Chengyong Zhu, Yingning Qiu, Yanhui Feng, Wei Zhong, Tongguang Wang
Summary: This paper investigates the rotational flow characteristics of the NREL Phase VI blade under axial and yawed inflow conditions using the DDES method. The rotational effects change the flow regime and suppress flow separation, leading to increased aerodynamic loads. The study shows that the rotational effects greatly influence the flow and aerodynamic performance of wind turbine blades, which can contribute to improved aerodynamic modeling.
Article
Mechanics
Xiaodong Liu, Haiyang Xu, Bohan Wang, Yuankui Wang, Chenglong Li, Yulin Si, Peng Qian, Dahai Zhang
Summary: This paper investigates the wake characteristic of a ducted turbine using flume experiments and large eddy simulations, proposing an analytical wake model of the ducted turbine and verifying it through different inflow velocities and tandem arrangements. The results show that the wake of a ducted turbine maintains a high self-similarity and approximately follows a double-Gaussian curve. Compared with a conventional tidal turbine, a ducted turbine has a faster wake recovery speed but a larger radial influence range, indicating the need for wider radial distances and shorter axial distances in ducted turbine arrays.
Article
Engineering, Marine
SeokKoo Kang, Youngkyu Kim, Jiyong Lee, Ali Khosronejad, Xiaolei Yang
Summary: The wake interactions between two horizontal axis model tidal turbines with different spacings were investigated using acoustic Doppler velocimetry (ADV). The study found that a velocity sampling time period of at least 1000 integral time scales is required for the convergence of turbulence statistics in the wake of the turbines. It was also observed that the increased turbulent momentum transfer by the first turbine overshadows its own effect.
Article
Energy & Fuels
Xiancheng Wang, Hao Li, Junhua Chen, Chuhua Jiang, Lingjie Bao
Summary: This paper investigates the blade solidity of the tidal current turbine. Two blade types with different solidities were designed based on the blade element momentum theory. The geometric parameters of the blades were calculated using MATLAB programming. Experimental tests were conducted to compare the performance of the two blades in terms of start-up flow rate, power generation, and thrust. The results show that the blade with higher solidity exhibits better start-up performance and higher energy capture efficiency at low flow rates, outperforming the blade with lower solidity. However, the high solidity also results in higher thrust, which should be taken into consideration when installing the turbine.
Article
Green & Sustainable Science & Technology
Jisheng Zhang, Siyuan Liu, Yakun Guo, Ke Sun, Dawei Guan
Summary: This study investigates the influence of different passive flow control devices on the performance of BHATT and designs and optimizes a series of centrosymmetric winglets to improve energy production.
Article
Engineering, Ocean
Siyuan Liu, Jisheng Zhang, Ke Sun, Dawei Guan
Summary: Horizontal-axis tidal turbines have the potential to generate clean renewable energy from ocean tides. A numerical model was used to study a bidirectional tidal turbine, and the results showed that it achieved a high power coefficient and caused remarkable flow characteristics in the near-wake. The presence of a support structure and misalignment had an impact on the turbine's performance.
APPLIED OCEAN RESEARCH
(2022)
Article
Engineering, Marine
Bin Xu, Xi Shen, Desheng Zhang, Jian Chen
Summary: This paper proposes an innovative methodology to improve hydrodynamic performance by optimizing blade shape. By using modified Blade Element Momentum (BEM) theory and particle swarm optimization algorithm, better performance of tidal current turbine can be achieved.
Article
Green & Sustainable Science & Technology
Hongwei Liu, Pengpeng Zhang, Yajing Gu, Yongdong Shu, Jiajun Song, Yonggang Lin, Wei Li
Summary: This study investigates the power train of a 650 kW horizontal-axis tidal current turbine, and develops a mathematical model to analyze the dynamic characteristics and the influence of external excitations. Simulation results show the increase in vibrations and bearing load fluctuation with tidal current velocity, and the dominant role of meshing motion in the vibration of the low-and high-speed shafts.
Article
Green & Sustainable Science & Technology
Jie Lin, Binliang Lin, Jian Sun, Yaling Chen
Summary: Horizontal axis turbines are considered promising energy extractors for tidal stream energy utilization, but there is still a lack of widely accepted model for describing the wake structure of tidal stream turbines. More experiments and data analysis are needed to improve the understanding of energy transformation and wake development processes, in order to enhance tidal stream energy extraction efficiency.
Article
Engineering, Ocean
Pengzhong Wang, Lu Wang, Qiang Zhang, Fuwei Zhu, Bin Huang
Summary: This paper introduces the design and manufacturing process of the largest megawatt-scale tidal current turbine in China, and studies its performance in detail through numerical simulation, experiment, and sea trial research. The analysis of the turbine's strength and fatigue life under different working conditions shows that it has good reliability and a working life of up to 20 years.
APPLIED OCEAN RESEARCH
(2023)
Article
Engineering, Mechanical
Joseph Banks, Alexander B. Phillips, Dominic A. Hudson, Stephen R. Turnock
Summary: Researchers used computational fluid dynamics to evaluate the propulsion and resistance forces of a swimmer. By combining passive resistance with momentum source terms, the study simulated the impact of body forces on fluid flow during swimming. Experimental data showed that the arms had no significant effect on the mean propelled resistance of a swimmer.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART P-JOURNAL OF SPORTS ENGINEERING AND TECHNOLOGY
(2021)
Article
Computer Science, Interdisciplinary Applications
M. Klapwijk, T. Lloyd, G. Vaz, T. van Terwisga
COMPUTERS & FLUIDS
(2020)
Article
Engineering, Mechanical
Rens Liebrand, Maarten Klapwijk, Thomas Lloyd, Guilherme Vaz
Summary: The study evaluates the impact of transition and turbulence modeling on predicting wetted and cavitating tip vortices for an elliptical wing, while investigating numerical errors. Transition modeling improves numerical predictions by avoiding underestimation of the tip vortex cavity size. The presence of the cavity alters the balance between production and destruction of turbulence kinetic energy, leading to reduced turbulent diffusion, resulting in vapor flow exhibiting characteristics of a potential flow which remains to be investigated for its physical plausibility.
JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME
(2021)
Article
Engineering, Marine
Giorgio Tani, Michele Viviani, Mario Felli, Frans Hendrik Lafeber, Thomas Lloyd, Batuhan Aktas, Mehmet Atlar, Serkan Turkmen, Hanshin Seol, Jan Hallander, Nobuaki Sakamoto
Article
Engineering, Marine
M. Klapwijk, T. Lloyd, G. Vaz, T. van Terwisga
Summary: The study investigates errors that occur when a laminar inflow is applied for mildly separated or attached flows, by employing partially averaged Navier-Stokes equations with varying values for the ratio of modelled-to-total turbulence kinetic energy and with varying grid densities. It is shown that depending on the grid resolution, laminar leading edge separation can occur, but when turbulent fluctuations are added to the inflow, the leading edge separation is suppressed completely and the turbulent separation zone near the trailing edge reduces in size. In cavitating conditions, the turbulence intensity has little effect on the pressure distribution, but has a large effect on the skin friction.
Article
Engineering, Industrial
Dana Dghaym, Thai Son Hoang, Stephen R. Turnock, Michael Butler, Jon Downes, Ben Pritchard
Summary: This paper presents an approach to identifying and analysing mission requirements for squads of autonomous missions, emphasizing the importance of clear definition of requirements for mission planning and management. By using formal modelling and analysis techniques, critical requirements that ensure the safety and security of the system are generated.
Article
Engineering, Mechanical
Maarten Klapwijk, Thomas Lloyd, Guilherme Vaz
Summary: Based on the k - root kL (KSKL) model, a new partially averaged Navier-Stokes (PANS) closure is derived, and it is demonstrated that this model maintains desirable features such as reduced eddy-viscosity, lower dependency on wall cell height, well-defined boundary conditions, and improved iterative convergence, for a range of turbulence kinetic energy ratios and even for multiphase flow.
JOURNAL OF FLUIDS ENGINEERING-TRANSACTIONS OF THE ASME
(2022)
Article
Computer Science, Interdisciplinary Applications
Sebastien Lemaire, Guilherme Vaz, Menno Deij-van Rijswijk, Stephen R. Turnock
Summary: This study presents a comprehensive investigation of interpolation schemes used in overset grid techniques, evaluating their robustness, accuracy, and performance through literature review and code verification exercises. It finds that the choice of interpolation scheme is dependent on the dominant physics in the flow and can have significant impact on the total discretization errors and numerical performance of the solver.
INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS
(2022)
Article
Engineering, Marine
Artur K. Lidtke, Maarten Klapwijk, Thomas Lloyd
Summary: This study investigates the effect of inflow turbulence on a circular cylinder at different turbulence intensities, finding that the proposed method successfully replicates relevant flow features. Increasing inflow turbulence intensity adds broadband frequency content to all fluctuating flow quantities.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2021)
Article
Engineering, Ocean
Jennie Andersson, Alex Abolfazl Shiri, Rickard E. Bensow, Jin Yixing, Wu Chengsheng, Qiu Gengyao, Ganbo Deng, Patrick Queutey, Yan Xing-Kaeding, Peter Horn, Thomas Luecke, Hiroshi Kobayashi, Kunihide Ohashi, Nobuaki Sakamoto, Fan Yang, Yuling Gao, Bjorn Winden, Max G. Meyerson, Kevin J. Maki, Stephen Turnock, Dominic Hudson, Joseph Banks, Momchil Terziev, Tahsin Tezdogan, Florian Vesting, Takanori Hino, Sofia Werner
Summary: This paper summarizes a CFD benchmark study comparing different predictions of the power reduction through installation of a pre-swirl duct (PSD) on a ship. The results show that the propeller model and wake field prediction are crucial factors affecting the predictions.
APPLIED OCEAN RESEARCH
(2022)
Article
Engineering, Marine
Artur K. Lidtke, Thomas Lloyd, Frans Hendrik Lafeber, Johan Bosschers
Summary: This study applies a combination of viscous computational fluid dynamics (CFD) and Ffowcs Williams-Hawkings acoustic analogy to validate the farfield radiated noise of propellers in cavitating conditions. The results show that the methodology can predict peak sound pressure levels within 5 dB of experimental results and accurately represent key features of the noise spectra.
Article
Engineering, Marine
M. Klapwijk, T. Lloyd, G. Vaz, M. van den Boogaard, T. Van Terwisga
Summary: The study focuses on predicting the dynamics and sound characteristics of cavitating tip vortices generated by an elliptical wing under different turbulence intensities. The results are validated against experiments and a semi-analytical model.
Article
Engineering, Marine
Daejeong Kim, Soonseok Song, Stephen Turnock, Tahsin Tezdogan
Summary: Accurately predicting the performance of maritime autonomous surface ships (MASS) in following predefined paths in waves is crucial for safe autonomous marine navigation. This study develops a CFD-based dynamic model to study path-following problems and comprehensively analyze path-following tasks under various wave conditions. The numerical results show that the greatest deviation from the predefined path occurs when the ship is maneuvering under beam and quartering seas due to the asymmetric pressure distribution on the ship hull caused by the incident waves. It is also confirmed that wave heights strongly affect the trajectories of the ship, with higher wave heights resulting in greater deviation from the predefined path. As computational resources improve, the proposed CFD method will provide an accurate and efficient way to predict the performance of autonomous surface ships in waves, enhancing the safety of autonomous marine navigation.
Article
Energy & Fuels
C. J. McKinlay, S. R. Turnock, D. A. Hudson
Summary: Reducing harmful emissions from international shipping is necessary, and this study analyzed the feasibility of using hydrogen fuel cells to meet auxiliary energy demand on large scale ships. The results showed that utilizing hydrogen fuel cells could significantly reduce fossil fuel consumption and CO2 emissions, potentially decarbonizing a significant portion of shipping energy demand.
Proceedings Paper
Computer Science, Interdisciplinary Applications
Rens Liebrand, Maarten Klapwijk, Thomas Lloyd, Guilherme Vaz, Rui Lopes
MARINE 2019: COMPUTATIONAL METHODS IN MARINE ENGINEERING VIII: VIII INTERNATIONAL CONFERENCE ONCOMPUTATIONAL METHODS IN MARINE ENGINEERING (MARINE 2019)
(2019)
Article
Green & Sustainable Science & Technology
Cameron Bracken, Nathalie Voisin, Casey D. Burleyson, Allison M. Campbell, Z. Jason Hou, Daniel Broman
Summary: This study presents a methodology and dataset for examining compound wind and solar energy droughts, as well as the first standardized benchmark of energy droughts across the Continental United States (CONUS) for a 2020 infrastructure. The results show that compound wind and solar droughts have distinct spatial and temporal patterns across the CONUS, and the characteristics of energy droughts are regional. The study also finds that compound high load events occur more often during compound wind and solar droughts than expected.
Article
Green & Sustainable Science & Technology
Ning Zhang, Yanghao Yu, Jiawei Wu, Ershun Du, Shuming Zhang, Jinyu Xiao
Summary: This paper provides insights into the optimal configuration of CSP plants with different penetrations of wind power by proposing an unconstrained optimization model. The results suggest that large solar multiples and TES are preferred in order to maximize profit, especially when combined with high penetrations of wind and photovoltaic plants. Additionally, the study demonstrates the economy and feasibility of installing electric heaters (EH) in CSP plants, which show a linear correlation with the penetration of variable energy resources.
Article
Green & Sustainable Science & Technology
M. Szubel, K. Papis-Fraczek, S. Podlasek
Article
Green & Sustainable Science & Technology
J. Silva, J. C. Goncalves, C. Rocha, J. Vilaca, L. M. Madeira
Summary: This study investigated the methanation of CO2 in biogas and compared two different methanation reactors. The results showed that the cooled reactor without CO2 separation achieved a CO2 conversion rate of 91.8%, while the adiabatic reactors achieved conversion rates of 59.6% and 67.2%, resulting in an overall conversion rate of 93.0%. Economic analysis revealed negative net present worth values, indicating the need for government monetary incentives.
Article
Green & Sustainable Science & Technology
Yang Liu, Yonglan Xi, Xiaomei Ye, Yingpeng Zhang, Chengcheng Wang, Zhaoyan Jia, Chunhui Cao, Ting Han, Jing Du, Xiangping Kong, Zhongbing Chen
Summary: This study investigated the effect of using nanofiber membrane composites containing Prussian blue-like compound nanoparticles (PNPs) to relieve ammonia nitrogen inhibition of rural organic household waste during high-solid anaerobic digestion and increase methane production. The results showed that adding NMCs with 15% PNPs can lower the concentrations of volatile fatty acids and ammonia nitrogen, and increase methane yield.
Article
Green & Sustainable Science & Technology
Zhong Ge, Xiaodong Wang, Jian Li, Jian Xu, Jianbin Xie, Zhiyong Xie, Ruiqu Ma
Summary: This study evaluates the thermodynamic, exergy, and economic performance of a double-stage organic flash cycle (DOFC) using ten eco-friendly hydrofluoroolefins. The influences of key parameters on performance are analyzed, and the advantages of DOFC over single-stage type are quantified.
Article
Green & Sustainable Science & Technology
Nicolas Kirchner-Bossi, Fernando Porte-Agel
Summary: This study investigates the optimization of power density in wind farms and its sensitivity to the available area size. A novel genetic algorithm (PDGA) is introduced to optimize power density and turbine layout. The results show that the PDGA-driven solutions significantly reduce the levelized cost of energy (LCOE) compared to the default layout, and exhibit a convex relationship between area and LCOE or power density.
Article
Green & Sustainable Science & Technology
Chunxiao Zhang, Dongdong Li, Lin Wang, Qingpo Yang, Yutao Guo, Wei Zhang, Chao Shen, Jihong Pu
Summary: In this study, a novel reversible liquid-filled energy-saving window that effectively regulates indoor solar radiation heat gain is proposed. Experimental results show that this window can effectively reduce indoor temperature during both summer and winter seasons, while having minimal impact on indoor illuminance.
Article
Green & Sustainable Science & Technology
Alessandro L. Aguiar, Martinho Marta-Almeida, Mauro Cirano, Janini Pereira, Leticia Cotrim da Cunha
Summary: This study analyzed the Brazilian Equatorial Shelf using a high-resolution ocean model and found significant tidal variations in the area. Several hypothetical barrages were proposed with higher annual power generation than existing barrages. The study also evaluated the installation effort of these barrages.
Article
Green & Sustainable Science & Technology
Francesco Superchi, Nathan Giovannini, Antonis Moustakis, George Pechlivanoglou, Alessandro Bianchini
Summary: This study focuses on the optimization of a hybrid power station on the Tilos island in Greece, aiming to increase energy export and revenue by optimizing energy fluxes. Different scenarios are proposed to examine the impact of different agreements with the grid operator on the optimal solution.
Article
Green & Sustainable Science & Technology
Peimaneh Shirazi, Amirmohammad Behzadi, Pouria Ahmadi, Sasan Sadrizadeh
Summary: This research presents two novel energy production/storage/usage systems to reduce energy consumption and environmental effects in buildings. A biomass-fired model and a solar-driven system integrated with photovoltaic thermal (PVT) panels and a heat pump were designed and assessed. The results indicate that the solar-based system has an acceptable energy cost and the PVT-based system with a heat pump is environmentally superior. The biomass-fired system shows excellent efficiency.
Article
Green & Sustainable Science & Technology
Zihao Qi, Yingling Cai, Yunxiang Cui
Summary: This study aims to investigate the operational characteristics of the solar-ground source heat pump system (SGSHPS) in Shanghai under different operation modes. It concludes that tandem operation mode 1 is the optimal mode for winter operation in terms of energy efficiency.
Article
Green & Sustainable Science & Technology
L. Bartolucci, S. Cordiner, A. Di Carlo, A. Gallifuoco, P. Mele, V. Mulone
Summary: Spent coffee grounds are a valuable biogenic waste that can be used as a source of biofuels and valuable chemicals through pyrolysis and solvent extraction processes. The study found that heavy organic bio-oil derived from coffee grounds can be used as a carbon-rich biofuel, while solvent extraction can extract xantines and p-benzoquinone, which are important chemicals for various industries. The results highlight the promising potential of solvent extraction in improving the economic viability of coffee grounds pyrolysis-based biorefineries.
Article
Green & Sustainable Science & Technology
Luiza de Queiroz Correa, Diego Bagnis, Pedro Rabelo Melo Franco, Esly Ferreira da Costa Junior, Andrea Oliveira Souza da Costa
Summary: Building-integrated photovoltaics, especially organic solar technology, are important for reducing greenhouse gas emissions in the building sector. This study analyzed the performance of organic panels laminated in glass in a vertical installation in Latin America. Results showed that glass lamination and vertical orientation preserved the panels' performance and led to higher energy generation in winter.
Article
Green & Sustainable Science & Technology
Zhipei Hu, Shuo Jiang, Zhigao Sun, Jun Li
Summary: This study proposes innovative fin arrangements to enhance the thermal performance of latent heat storage units. Through optimization of fin distribution and prediction of transient melting behaviors, it is found that fin structures significantly influence heat transfer characteristics and melting behaviors.
