Journal of Hydroelectric Engineering

水力发电学报

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The journal is included in the following databases:
(i)Scopus,
(ii)The Chinese Science Citation Database Source Journals,
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(vi)Chinese Academic Journals (CD).


2021 Vol. 40, No. 6 Published: 2021-06-25

	1	Operational load identification for offshore wind turbines based on five points method
		JIANG Qi, DONG Xiaofeng, WENG Peiyao, LIAN Jijian
		DOI: 10.11660/slfdxb.20210601
		Reliable load information is a key factor in evaluating the fatigue and rest life cycle, but continual load monitoring is often difficult in engineering practice. Aimed at the dynamic characteristics and load features of offshore wind turbines, this paper presents a time-domain load identification technique, based on the five points method, which can eliminate the influence of initial value, suppress the influence of error transfer, and reduce accumulative errors so as to improve its stability and robustness. First, this method is verified via application to several validation cases using the spring-mass damping model; then, it is applied to a 5 MW monopile offshore wind turbine provided by Facility for Accelerated Service Testing (FAST). The results show that the method can identify turbine operational loads accurately and stably, with its results not influenced by wind speed or operation strategy control.
		2021 Vol. 40 (6): 1-11 [Abstract] ( 152 ) PDF (4387 KB) ( 429 )

	12	Effect of rear guide vanes on performance of tidal bidirectional tubular turbines
		ZHU Guojun, FENG Jianjun, GE Zhenguo, LIU Keran, LUO Xingqi
		DOI: 10.11660/slfdxb.20210602
		Tidal bidirectional tubular turbines, unlike conventional units, need to consider both forward and reverse flow conditions. To balance and improve their performance under these two operating modes, this study investigates the effect of the position and number of different rear guide vanes on the performance and internal flow characteristics, using ANSYS CFX for flow simulations and taking a real project unit as a test case. The results show the position and number of these vanes have a great impact on the generating unit in reverse mode. The overall performance is better at a vane position coefficient of 0.5 and a vane number of eight. In forward mode, with the increase in the vane number, head loss decreases in draft tube but increases in rear vane channels; in reverse mode, the runner has a decreasing head loss and a gradually increasing efficiency. The results are useful for optimization design of the key flow components of tidal bidirectional tubular turbines.
		2021 Vol. 40 (6): 12-20 [Abstract] ( 153 ) PDF (4074 KB) ( 417 )

	21	Optimization of hydrogen production systems for energy curtailment utilization at run-of-river hydropower stations
		YANG Yang, WANG Xiaoqun, LIAN Chong, ZHANG Yusheng, WU Zhen
		DOI: 10.11660/slfdxb.20210603
		Considering the serious situation of power curtailment by hydropower stations in China, this study examines the optimization of hydrogen production systems for utilizing energy curtailment at run-of-river hydropower stations of little reservoir regulation capacity. We develop a method for calculating the curtailment using the inflow hydrograph of a reservoir and the operation characteristics of its generating units, and constructs complete integrated operation control strategies and a capacity allocation optimization model for comprehensive consideration of production, storage and transport of water energy. And sensitivity analysis on the relationship of the annual average hydrogen production and hydrogen market price versus the economic benefit of the system is carried out. Example calculations of the Shaping Ⅱ hydropower station in Sichuan show that when the transport distance of liquid hydrogen is 500 km and the hydrogen unit price is 3.5 yuan/Nm3, the curtailment utilization rate via a hydrogen production system of optimal capacity configuration in 2019 is 70.54%, bringing about a hydrogen production of 20.9 million Nm3 and a net present value of the whole life cycle of 199 million yuan. This study demonstrates a hydrogen production system could be a new approach to power curtailment problems, clean energy power utilization, and promotion of the hydrogen economy in China.
		2021 Vol. 40 (6): 21-30 [Abstract] ( 181 ) PDF (1412 KB) ( 490 )

	31	Study on accuracy evaluation and substitutability of multiple precipitation products on Loess Plateau
		WU Haizhe, LIU Dengfeng, HUANG Qiang, ZHENG Hongwei, ZOU Hao, YE Nan, LIN Mu
		DOI: 10.11660/slfdxb.20210604
		Precipitation products provides a new data source for hydrological research of data-poor areas. This paper analyzes quantitatively multi-temporal and multi-spatial scale accuracy and application potential of multi-source fusion precipitation products (CMFD and MSWEP) and an atmospheric assimilation dataset (CMADS) combined with the observation data from the ground stations in the Weihe River basin. The watershed distributed hydrological model, SWAT, is used to explore the substitutability of these precipitation products for the ground-measured precipitation data of the basin in simulations of the river daily flow. The results show that the three precipitation datasets can basically reflect the spatial distribution of precipitation over the basin, but a certain degree of deviation exists. MSWEP performs better at various time scales, and its average error at daily scale is only 0.05 mm. Simulation accuracies forced by the precipitation data recalibrated using adjustable parameters are significantly improved over those in fixed parameter scenarios, indicating a practical approach to effective simulation of the basin’s daily hydrograph. Thus, this study shows that in hydrological simulations, precipitation products have potential to replace precipitation measurements at the ground stations in the Weihe River basin.
		2021 Vol. 40 (6): 31-40 [Abstract] ( 175 ) PDF (1540 KB) ( 318 )

	41	Assessment to total water consumption control and governance effects in inland river basin of Northwest China. Case study of Heihe and Shiyang River basins
		HU Zhidan, WANG Zhongjing, ZHENG Hang
		DOI: 10.11660/slfdxb.20210605
		Implementation of total water consumption control and key watershed management over the inland river basins in the Northwest China can promote sustainable utilization of water resources and improve ecosystem and environment. This paper describes an index system for evaluating the total water consumption control and basin governance effects, and presents a comprehensive assessment that uses the weighted average method and quantifies index scoring values and index weights. This method is tested via applications to the Heihe River basin and Shiyang River basin in the Hexi Corridor. The results show that it can reflect the implementation conditions of total water consumption control and governance over the two basins comprehensively and reveal problems through quantitative analysis of the system structure, so that it will help strengthen the construction of total water consumption control system and improve river basin governance. For these two basins, our assessment demonstrates that most of the total water consumption control targets have been achieved and most of the river basin governance tasks have been done, and that the established system is overall successful.
		2021 Vol. 40 (6): 41-50 [Abstract] ( 195 ) PDF (1158 KB) ( 298 )

	51	Characteristics of precipitation in Xijiang River basin from 1970 to 2017
		SU Heng, XU Zongxue, LI Peng, YE Chenlei, WANG Jingjing
		DOI: 10.11660/slfdxb.20210606
		Based on the 1970-2017 daily precipitation data at 37 meteorological stations over the Xijiang River basin, temporal and spatial characteristics of the precipitation in this basin are analyzed using the moving average method, Mann-Kendall trend test, Sen's slope, wavelet transform, and empirical orthogonal function. Results indicate that the annual precipitation in the basin showed an insignificant decreasing trend, with a dominant cycle of 29 years, and a spatial distribution featured with a decreasing trend from east to west and north to south. In a year, most of the precipitation was concentrated in summer, and the winter season contributed the smallest proportion. It showed a decreasing trend in spring and autumn while an increasing trend in summer and winter, but the trend was significant only in spring. The precipitation was the greatest in June and showed small values of insignificant variations over the period of December to February. The precipitation concentration degree (PCD) was generally considerable large. The spatial distributions of PCD and precipitation concentration period (PCP) decreased from west to east, but their first and second modal coefficients did not show consistent or anisotropic feature in spatial distribution probably owing to the diversified causes of precipitation.
		2021 Vol. 40 (6): 51-61 [Abstract] ( 176 ) PDF (5959 KB) ( 662 )

	62	Review of low impact development rainwater system planning
		YANG Fengru, CHEN Liang, ZHANG Yazhuo, GUO Qizhong, LIAN Jijian, LI Mengmeng
		DOI: 10.11660/slfdxb.20210607
		In control and management of urban rainwater, rational rainwater system planning is critical to improvement on runoff control effect and utilization benefit of rainwater. This paper summarizes two different perspectives－pattern guide and goal guide－commonly used in the planning of low impact development rainwater systems in sponge city construction, and discusses the principles, steps, advantages and disadvantages of each method. Results show problems remain in the planning and research of these systems in China, such as difficult coordination between the space planning and scale of a rainwater system, lack of a site condition comparison system for different low impact development facilities, insufficient analysis of stakeholder preferences for such a system, and deficiencies in the cost-benefit assessment systems for the facilities.
		2021 Vol. 40 (6): 62-78 [Abstract] ( 249 ) PDF (3720 KB) ( 492 )

	79	Hydrodynamics of juvenile grass carp (Ctenopharyngodon idellus) in steady swimming based on pressure field
		ZHANG Ben, HU Xiao, YANG Guodang, LONG Zeyu, HUANG Huiling, SHI Xiaotao
		DOI: 10.11660/slfdxb.20210608
		To study the formation and mechanism of fluid thrust and drag on a fish during its steady swimming, this paper presents an analysis on the characteristics of pressure distribution and fluid forces around a juvenile grass carp (Ctenopharyngodon idellus), using the particle image velocimetry (PIV) technology for velocity measurement. The results show that during the movement of the carp, the thrust of surrounding fluid on its body and its time variation depend on the positive pressure distribution on its body, while the negative pressure distribution dominates fluid drag formation. The experimental data reveal the proportions of thrust generated by the positive and negative pressure on the fish are 59.0% and 41.0% respectively. The swimming efficiency is (80.2±17.5)% based on positive pressure and (58.8±25.8)% based on negative pressure, and the drag proportion from negative pressure is as high as 81.9%. The thrust proportions on the fish’s head, middle and tail is 13.7%, 38.5% and 47.8% respectively; the drag proportion on its middle part reached up to 72.8%. Its whole body contributes to thrust generation, while the tail is the main source of thrust and the highest swimming efficiency is (77.2±12.1)%. The results of this study helps deepen the understanding of fish swimming dynamics and mechanism and is useful in fish bionics application and ecological protection.
		2021 Vol. 40 (6): 79-88 [Abstract] ( 144 ) PDF (2446 KB) ( 251 )

	89	Intelligent text classification method for water diversion project inspection based on character level CNN
		LIU Ting, ZHANG Sherong, LI Zhihong, GUAN Wei
		DOI: 10.11660/slfdxb.20210609
		Daily safety inspection is an important means to maintain the safe operation of long-distance water diversion projects. At present, unstructured text data collected from patrol inspection mainly rely on manual safety level evaluation, which has obvious deficiencies in work efficiency and accuracy. Based on natural language processing technologies, this paper describes an intelligent text classification method of character oriented convolutional neural network (CNN). This method improves the CNN input layer by introducing a pre-trained single character vector, allowing the classification model to extract feature information directly from the text; it not just avoids dependency of traditional classification methods on the professional lexicon, but its results are not easily affected by the colloquial expressions and typographical errors in the text. Taking the inspection text of a domestic water diversion project as a test case, its effectiveness and superiority are verified through comprehensive comparison with several deep learning algorithms. Results show that the character level classification is much better than the traditional words based method, and CNN is significantly better than other deep learning networks in classification of the patrol inspection texts. Our method provides a new intelligent means with high classification efficiency and accuracy for the safety maintenance of water diversion projects.
		2021 Vol. 40 (6): 89-98 [Abstract] ( 263 ) PDF (492 KB) ( 552 )

	99	Partial factor method for rockfill dam slope stability. Theory and calibration
		CHEN Zuyu, ZHOU Heng, LU Xi, YUAN Youren, LI Kangping
		DOI: 10.11660/slfdxb.20210610
		The design methods based on reliability analysis can consider variations and uncertainties in input parameters to certain extent, while a partial factor method based on probability limit state provides a simple and effective approach in engineering practice. Based on reliability analysis and verification using a historical empirical model, the principle of the partial factor method and its coefficient calibration are investigated comprehensively in this paper. Results show the partial factors of cohesion γc and friction coefficient γf for dam materials should be 1.20 and 1.10 respectively. We suggest that the structural importance coefficient γ0 of grades I (grade 1 rockfill dams), II (grades 2 and 3 rockfill dams) and III (grades 4 and 5 rockfill dams) structures be 1.10, 1.05 and 1.00 respectively. And for super high dams, the structural coefficient γd be 1.30-1.35. These safety control indexes are verified through comparison with those of 15 rockfill dams built in China, thus helping revise the new design code.
		2021 Vol. 40 (6): 99-116 [Abstract] ( 143 ) PDF (836 KB) ( 306 )

	117	New filter void model for calculating infiltration depths of particles
		YANG Peiyao, WANG Hongyu, ZHANG Gang, LI Xing, HE Jinsha, CHAI Pengxiang
		DOI: 10.11660/slfdxb.20210611
		To investigate further the seepage erosion mechanism and predict the distribution of particles washed away in the filter system, this paper develops a filter void network model for the dense state of filling soil. Predictions of this model are analyzed and compared with those of two previous models in the literature in terms of the depth of base particles infiltrating into the filter, as well as with numerical simulations; And its feasibility and applicability are verified further in an engineering case. The results show the model of Locke and Indraratna gives the largest infiltration depth among the three; our new model predicts a depth smaller than that of Silveira’s model when the probability of base particles passing the constriction is low, while it predicts infiltration depths increasingly greater than Silveira’s as the passing probability increases. Variation trends in its maximum infiltration depths at the characteristic particle size ratio D15/d85 are the same as those in Zou’s simulations, but a greater discrepancy appears between the two calculations due to the limitation of Zou’s in soil sample size and infiltration time, especially at a size ratio close to or greater than 4 (the threshold value in the filter criteria). Our void model is a new approach for the filter design of real projects when the filter gradation design envelope is confirmed.
		2021 Vol. 40 (6): 117-126 [Abstract] ( 130 ) PDF (780 KB) ( 269 )

	127	μ(I) rheology-based three-dimensional numerical model for landslide motions
		LIU Zhankui, FEI Jianbo, JIE Yuxin
		DOI: 10.11660/slfdxb.20210612
		Landslide is a widespread and frequent natural disaster, and its behaviors can be studied using appropriate numerical methods, through simulating its moving process and then predicting and analyzing the potential disaster. This paper describes a three-dimensional landslide numerical method for landslide motions based on the continuum theory and μ(I) rheology of granular flows. We use the Navier-Stokes equations and μ(I) rheology to develop the continuity equation and momentum equation of landslide motions, apply a finite volume method for discretization, and construct a simulation solver based on OpenFOAM, an open source platform. Application to simulations of the inclined rough plane laboratory test verifies the feasibility of this method.
		2021 Vol. 40 (6): 127-138 [Abstract] ( 229 ) PDF (2652 KB) ( 589 )

	139	Intelligent data mining approach of text entity knowledge from construction documents of concrete dams
		TIAN Dan, SHEN Yang, LI Mingchao, HAN Shuai
		DOI: 10.11660/slfdxb.20210613
		The construction information of concrete dams is mostly expressed in form of document text, which is characterized by a wealth of information, wide distribution, and complex internal relations; manual operation finds it difficult to accurately extract information knowledge and sort out complicated relationships of construction information. In natural language processing, named entities are the carriers of text information, and realizing accurate and fast entity recognition is an important premise of construction knowledge mining. This paper describes a knowledge intelligent recognition and analysis method that combines deep learning and association rule technique for processing the construction documents of concrete dams. The types of concrete dam construction entities are defined; the bi-directional long-short term memory (Bi-LSTM) and conditional random field (CRF) methods are used to build named entity recognition models and generate construction entity knowledge sets. Further, we develop an entity association rule extraction technique by considering the expression rules and entity types of the text, predefining the relationships between the entities, and determining their combination forms. And we use this method to improve the Apriori algorithm and obtain strong association rules by calculating the frequent itemset. Application to the weekly report text for construction supervision of a concrete dam verifies the method, and shows its accuracy of 86.4% in recognition of named entities. The improved Apriori algorithm is used to analyze the association rules between the entities, demonstrating its advantages and usefulness in raising the intelligence and refinement level of document knowledge extraction and analysis for concrete dam construction.
		2021 Vol. 40 (6): 139-151 [Abstract] ( 248 ) PDF (793 KB) ( 588 )

	152	Influence mechanism of pore liquid viscosity on concrete strength under dynamic loading
		ZHENG Dan, LIANG Yuntao, LI Xinxin
		DOI: 10.11660/slfdxb.20210614
		This paper discusses the influence mechanism of pore liquid viscosity on concrete strength under dynamic loading. We conduct an experimental study on the dynamic behaviors of concrete materials under different conditions: dry, water-saturated, filled with liquids of different viscosity, and high-temperature baking. Influence of filling liquid viscosity on concrete strength under dynamic loading is analyzed using its strength increase and dynamic increase factor separately; multiple regression analysis is used to examine the impacts of pore liquid viscosity and loading rate on concrete strength under dynamic loading. On the basis of statistical analysis on the test data from previous studies and of our own, we analyze internal water migration in concrete, and discuss the influence mechanism of pore water and capillary water on the dynamic properties of concrete. We show that under seismic loading, it is more reasonable to use absolute values to describe concrete strength increase corresponding to the range of strain rates. And, no considerable difference in strength increase has been observed between dry and saturated concretes, and the effect of viscosity on concrete strength is mainly from capillary water inside the material.
		2021 Vol. 40 (6): 152-159 [Abstract] ( 127 ) PDF (1196 KB) ( 428 )

	160	Improvement and review of rationality of temperature control curves for super-high arch dams
		WU Jianming, LI Qingbin, TAN Yaosheng, LIU Chunfeng, PEI Lei, WANG Yajun, HU Yu
		DOI: 10.11660/slfdxb.20210615
		As the intelligent temperature control technology improves, the temperature control model of three phases and nine stages for casting super-high arch dam concrete will be simplified, so that it can further improve the internal stresses of concrete. With consideration of the construction monitoring data, this paper suggests and examines two new simplified temperature control models: one phase and three stages and two phases and six stages; and presents an analysis, through numerical simulations using these models, of the strengths and weaknesses of different time variations in the internal stress of the arch dam under cooling control at each stage. The results show that of the three models, one phase and three stages has the weakest stress impact when the concrete is cooled down from the highest to arch sealing temperature in the shortest time; its maximum stress is much lower than those of the other two models. All the three stress curves are well below the safety threshold curve when arch sealing temperature is reached at 120, 150 and 180 days, and they only extend the duration of water circulation and have little effect on dam stress. For the three phases and nine stages model, the key to reducing stress in the dam body is to reasonably adjust the cooling rate and the ratio of cooling time to temperature control time.
		2021 Vol. 40 (6): 160-168 [Abstract] ( 135 ) PDF (999 KB) ( 386 )

	169	Microscopic damage detection of sandstone using digital core technology
		YIN Duohao, XU Qianjun
		DOI: 10.11660/slfdxb.20210616
		Detection of microstructures is important for the study of sandstone damage. In this paper, CT scan tests are conducted on sandstone specimens before and after damage; pore throat analysis and finite element simulations of representative volume elements (RVEs) are conducted using digital rock core technology to quantitatively characterize the microscopic damage to sandstone and explore its mechanism. We count the pore defects of sandstone through 3D reconstruction of the sandstone microstructure from the CT scan images, obtain the effective bearing area, and compare it with elastic modulus, verifying CT images can reflect sandstone damage. The pore throat characteristic parameter of RVEs is significantly affected by damage, where the increases in the throat length and pore coordination number are two major factors contributing to microscopic damage. We interface the CT processing software Avizo with the finite element software Comsol to implement elastic modulus simulations of RVEs, proving digital rock cores can unify macroscopic and microscopic damage to sandstone.
		2021 Vol. 40 (6): 169-178 [Abstract] ( 172 ) PDF (4132 KB) ( 349 )