International Marine Energy Journal最新文献_第7页

Spanwise flow corrections for tidal turbines 潮汐涡轮机的跨度流量校正

International Marine Energy Journal Pub Date : 2018-11-01 DOI: 10.36688/IMEJ.1.111-121

A. Wimshurst, R. Willden

{"title":"Spanwise flow corrections for tidal turbines","authors":"A. Wimshurst, R. Willden","doi":"10.36688/IMEJ.1.111-121","DOIUrl":"https://doi.org/10.36688/IMEJ.1.111-121","url":null,"abstract":"Actuator line computations of two different tidal turbine rotor designs are presented over a range of tip speed ratios. To account for the reduction in blade loading on the outboard sections of these rotor designs, a spanwise flow correction is applied. This spanwise flow correction is a modified version of the correction factor of Shen et al. (Wind Energy 2005; 8: 457-475) which was originally developed for wind turbine rotors at high tip speed ratios. The modified correction is described as ‘directionally dependent’ in that it allows a more aggressive reduction in the tangential (torque producing) direction than the axial (thrust producing) direction and hence allows the sectional force vector to rotate away from the rotor plane (towards the streamwise direction). When using the modified correction factor, the actuator line computations show a significant improvement in the accuracy of prediction of the rotor thrust and torque, when compared to similar actuator line computations that do not allow the sectional force vector to rotate. Furthermore, the rotation of the sectional force vector is attributed to the changing surface pressure distribution on the outboard sections of the blade, which arises from the spanwise flow along the blade. The rotation of the sectional force vector can also be used to explain the reduction in sectional lift coefficient and increase in sectional drag coefficient that has been observed on the outboard blade sections of several rotors in the literature","PeriodicalId":36111,"journal":{"name":"International Marine Energy Journal","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44195054","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 5

Using Blade Element Momentum Theory to Predict the Effect of Wave-Current Interactions on the Performance of Tidal Stream Turbines 用叶片单元动量理论预测波流相互作用对潮流涡轮机性能的影响

International Marine Energy Journal Pub Date : 2018-09-09 DOI: 10.36688/IMEJ.4.25-36

S. Fu, S. Ordoñez-Sanchez, R. Martinez, C. Johnstone, Matthew Allmark, T. O’Doherty

{"title":"Using Blade Element Momentum Theory to Predict the Effect of Wave-Current Interactions on the Performance of Tidal Stream Turbines","authors":"S. Fu, S. Ordoñez-Sanchez, R. Martinez, C. Johnstone, Matthew Allmark, T. O’Doherty","doi":"10.36688/IMEJ.4.25-36","DOIUrl":"https://doi.org/10.36688/IMEJ.4.25-36","url":null,"abstract":"The non-uniformity and dynamics of the environment tidal stream turbines need to operate within will significantly influence the durability and reliability of tidal energy systems. The loadings on the turbine will increase substantially when the turbine is deployed in high magnitude waves with non-uniform tidal currents. The limitations of numerical solutions will be understood when the outcomes are verified with empirical data from system operations. In this paper, a Blade Element Momentum model is used to predict and compare the performance of a scaled turbine within a flume and a tow tank. Firstly, the numerical and experimental work is analysed for a turbine operating at flow speeds of 0.5m/s amd 1.0 m/s, wave heights of 0.2 m and 0.4 m and wave periods of 1.5 s and 1.7 s. Good agreement between the model and the experimental work was observed. However, in low TSRs the model tends to under predict the thrust, and the variation between the maximum and minimum values obtained within the experiments. Secondly, a turbine operating at flow speeds of 1.0 m/s and 4 different inflow profiles is analysed, where the wave heights for these cases were 0.09 m and 0.19 m and with wave periods of 2 s and 1.43 s. In this evaluation, the model tends to over predict the values of Ct and Cp when compared to those calculated from the experimental data. However, when investigating the values used to calculating both the thrust and torque coefficients, there is better agreement with these, which means the methodology used to determine these coefficients with inflow profiles should be revised. ","PeriodicalId":36111,"journal":{"name":"International Marine Energy Journal","volume":"4 1","pages":"25-36"},"PeriodicalIF":0.0,"publicationDate":"2018-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46032625","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Preface to the special issues of the Twelfth European Wave and Tidal Energy Conference (EWTEC 2017) 第十二届欧洲波浪与潮汐能会议(EWTEC 2017)特刊前言

International Marine Energy Journal Pub Date : 2018-09-04 DOI: 10.36688/imej.1.v

A. W. Lewis (Chair, EWTEC 2017)

引用次数: 0

Performance and wake characteristics of a tidal turbine under yaw 偏航下潮汐涡轮机性能及尾流特性

International Marine Energy Journal Pub Date : 2018-09-03 DOI: 10.36688/IMEJ.1.41-50

P. Modali, Nitin Kolekar, A. Banerjee

{"title":"Performance and wake characteristics of a tidal turbine under yaw","authors":"P. Modali, Nitin Kolekar, A. Banerjee","doi":"10.36688/IMEJ.1.41-50","DOIUrl":"https://doi.org/10.36688/IMEJ.1.41-50","url":null,"abstract":"In tidal streams and rivers, the flow of water can be at yaw to the turbine rotor plane causing performance degradation and a skewed downstream wake. The current study aims to quantify the performance variation and associated wake behavior caused by a tidal turbine operating in a yawed inflow environment. A three-dimensional computational fluid dynamics study was carried out using multiple reference frame approach using κ-ω SST turbulence model with curvature correction. The computations were validated by comparison with experimental results on a 1:20 scale prototype for a 0° yaw case performed in a laboratory flume. The simulations were performed using a three-bladed, constant chord, untwisted tidal turbine operating at uniform inflow. Yaw effects were observed for angles ranging from 5° to 15°. An increase in yaw over this range caused a power coefficient deficit of 26% and a thrust coefficient deficit of about 8% at a tip speed ratio of 5 that corresponds to the maximum power coefficient for the tested turbine. In addition, wake propagation was studied up to a downstream distance of ten rotor radius, and skewness in the wake, proportional to yaw angle was observed. At higher yaw angles, the flow around the turbine rotor was found to cushion the tip vortices, accelerating the interaction between the tip vortices and the skewed wake, thereby facilitating a faster wake recovery. The center of the wake was tracked using a center of mass technique. The center of wake analysis was used to better quantify the deviation of the wake with increasing yaw angle. It was observed that with an increase in yaw angle, the recovery distance moved closer to the rotor plane. The wake was noticed to meander around the turbine centerline with increasing downstream distance and slightly deviate towards the free surface above the turbine centerline, magnitude of which varied depending on yaw.","PeriodicalId":36111,"journal":{"name":"International Marine Energy Journal","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48754911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 10

Strategic timing of commercial-scale tidal energy investment 商业规模潮汐能投资的战略时机

International Marine Energy Journal Pub Date : 2018-09-03 DOI: 10.36688/imej.1.35-40

S. MacDougall

{"title":"Strategic timing of commercial-scale tidal energy investment","authors":"S. MacDougall","doi":"10.36688/imej.1.35-40","DOIUrl":"https://doi.org/10.36688/imej.1.35-40","url":null,"abstract":"The many uncertainties in tidal energy conversion combine to form a significant barrier to raising private-sector capital. Mitigation and management of risk are essential if the industry is to attract equity investors. One way to manage the risk is through investment timing. The option to time an investment has value, which can be estimated. An analysis of an invest-vs-delay decision revealed a persistent, economicallyrational incentive to delay. Further inquiry identified a strategic rationale for delaying investment in tidal energy projects, given the uncertainty still present in the undertaking. As the largest sensitivity in the value of delay is the volatility of the investment’s expected cash flows, an investigation into the prevalent uncertainties was undertaken. \u0000This paper summarizes the real option valuation model. It then reports on results of a qualitative study of the predominant uncertainties facing developers and conditions that would help move the industry along. Predominant uncertainties reported revolve around technology reliability; site and resource knowledge; prospects for buildout; predictability of government policy and supports; prospects of off-take agreements; and supply chain capacity and costs. These are related back to the variables in the real option pricing model. The model is relevant for companies wishing to systematically evaluate timing options and communicate project value to the investment community. It can also be used by governments to evaluate the design of policies and financial supports in a way that is consistent with the priorities of financial markets.","PeriodicalId":36111,"journal":{"name":"International Marine Energy Journal","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48586324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Development of a methodology for collaborative control within a WEC array WEC阵列协同控制方法的开发

International Marine Energy Journal Pub Date : 2018-09-03 DOI: 10.36688/imej.1.51-59

Paul-Emile Meunier, A. Clément, J. Gilloteaux, K. Sofien

引用次数: 4

Designing multi-rotor tidal turbine fences 设计多转子潮汐涡轮机围栏

International Marine Energy Journal Pub Date : 2018-09-03 DOI: 10.36688/IMEJ.1.61-70

C. Vogel, R. Willden

{"title":"Designing multi-rotor tidal turbine fences","authors":"C. Vogel, R. Willden","doi":"10.36688/IMEJ.1.61-70","DOIUrl":"https://doi.org/10.36688/IMEJ.1.61-70","url":null,"abstract":"An embedded Reynolds-Averaged Navier-Stokes blade element actuator disk model is used to investigate the hydrodynamic design of tidal turbines and their performance in a closely spaced cross-stream fence. Turbines designed for confined flows are found to require a larger blade solidity ratio than current turbine design practices imply in order to maximise power. Generally, maximum power can be increased by operating turbines in more confined flows than they were designed for, although this also requires the turbines to operate at a higher rotational speed, which may increase the likelihood of cavitation inception. In-array turbine performance differs from that predicted from single turbine analyses, with cross-fence variation in power and thrust developing between the inboard and outboard turbines. As turbine thrust increases the cross-fence variation increases, as the interference effects between adjacent turbines strengthen as turbine thrust increases, but it is observed that cross-stream variation can be mitigated through strategies such as pitch-to-feather power control. It was found that overall fence performance was maximised by using turbines designed for moderately constrained (blocked) flows, with greater blockage than that based solely on fence geometry, but lower blockage than that based solely on the turbine and local flow passage geometry to balance the multi-scale flow phenomena around tidal fences.","PeriodicalId":36111,"journal":{"name":"International Marine Energy Journal","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46166450","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

A method for the spatial targeting of tidal stream energy policies 潮汐流能源政策的空间定位方法

International Marine Energy Journal Pub Date : 2018-08-31 DOI: 10.36688/imej.1.19-26

A. Vázquez, S. Astariz, G. Iglesias

{"title":"A method for the spatial targeting of tidal stream energy policies","authors":"A. Vázquez, S. Astariz, G. Iglesias","doi":"10.36688/imej.1.19-26","DOIUrl":"https://doi.org/10.36688/imej.1.19-26","url":null,"abstract":"Policy making is called to play a decisive role in the commercialisation of tidal stream energy projects. For they are site-specific, spatial targeting of policies is needed, so that tidal stream regulations (financial supporting mechanisms, consenting procedures, etc.) could be concentrated to sites where they can achieve the greatest benefits. With this in view, the aim of this paper is: (i) to develop a new method to delimit the most suitable (target) areas for tidal stream energy policy intervention within a coastal area of interest, and (ii) to apply it to the Bristol Channel and Severn Estuary (UK). The method includes spatial numerical analysis by means of a Matlab-based code coupled with a Navier-Stokes solver. The programme works in steps, in which different constraints are imposed with a view to carry out a zoning process. As a result of this zoning process, four hotspots are selected, for which a set of policy interventions is proposed. This includes the specific levels of subsidisation for closing the grid parity gap of potential projects in each area. The method can be viewed as a supporting decision mechanism for spatially targeted policy-making and management of tidal stream energy across the Bristol Channel and Severn Estuary.","PeriodicalId":36111,"journal":{"name":"International Marine Energy Journal","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2018-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42304420","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Applying a simple model for estimating the likelihood of collision of marine mammals with tidal turbines 应用一个简单的模型来估计海洋哺乳动物与潮汐涡轮机碰撞的可能性

International Marine Energy Journal Pub Date : 2018-08-31 DOI: 10.36688/IMEJ.1.27-33

A. Copping, M. Grear

引用次数: 10

Ocean energy in Europe 欧洲的海洋能源

International Marine Energy Journal Pub Date : 2018-08-30 DOI: 10.36688/IMEJ.1.1-7

D. Magagna, R. Monfardini, A. Uihlein

引用次数: 9