bluuebunny/crossref_metadata_2025_split huggingface dataset:
Research and Practice of Passive Low Energy Residential Design in Rural Areas of Semi-Urbanized Regions in Hot-summer and Cold-winter Zone
Authors: Qin Yuanyuan , Zhou Tiejun 
Published: June 2021

Abstract
The applicability of urban building energy-saving ideas and technologies to rural house deserves reflection. It requires to clarify the key points for rural house energy-saving in theory and practical exploration. Principles of Rural Passive Low Energy Residence should be: passive technology preferred and make full use of local conditions, cope with specific comfort standards and moderately enhance envelope performance, optimize energy supply structure and technical benefits should be obvious with reasonable costs. This paper takes the rural house case study design in Yongsheng Village as an example to carry out the research. Based on the principle of “passive priority and active optimization”, the residential design makes full use of the potential of local microclimate, plane meets the living needs of winter and summer moderately improves the performance of envelope, takes wind tunnel as auxiliary temperature regulation system, and adopts distributed photovoltaic power generation system to provide domestic energy. The practice has achieved good operation results and obvious economic benefits. It provides an engineering example for the implementation of passive low energy technology in rural.
Comprehensive Measuring the Development Level of Water Resources Circular Economy in Beijing-Tianjin-Hebei Urban Agglomeration
Authors: Yang Jing , Jing Ping , Gao Die 
Published: June 2021

Abstract
With the rapid increasing population and rapid economic development, water shortages and water environmental pollution problems have become increasingly prominent. In this paper, based on the concept of circular economy, starting from the four dimensions of water supply, water use, drainage, and regeneration, the comprehensive evaluation index system was established for Beijing-Tianjin-Hebei about water resource circular economy, the entropy weight method is used to determine the index weight, and the weighted comprehensive index method is used to comprehensively evaluate the development level of water resources circular economy. The results show that the development level of water resources circular economy has spatial heterogeneity in 13 cities of Beijing-Tianjin-Hebei from 2012 to 2016, which is in a state of unbalanced development. The utilization of water resources in Beijing and Tianjin is significantly better than that of other cities in Hebei Province. Only Chengde and Qinhuangdao have better water resources recycle in Hebei Province.
Particle Parameters of Asphalt Pavement Milling Recycling Material
Authors: Jing Jing , Fan Liang , Zhou Shengjie , Zhang Chi , Gao WenChen , Zhan Wang 
Published: June 2021

Abstract
Based on laboratory data and literature data, this paper has carried out a study on the particle parameters of asphalt pavement milling recycled materials. From the two indicators of the characteristic particle size and uniformity of the aggregate, the difference between the particle characteristics of the new aggregate and the recycled material, the changes in the composition of the macroscopic particles after the recycled material are extracted in advance and the attenuation law of the asphalt mixture gradation during the service time of the road surface was studied in this paper. The results show that based on the RRS equation, the particle distribution simulation of aggregates, RAP materials and mixtures can be simulated, and two characterization parameters of characteristic particle size and uniformity coefficient can be obtained. Under the condition of the same particle size range, the characteristic particle size of RAP material is smaller than that of the new aggregate, the uniformity improved, and the particle size distribution range becomes narrow. There is a good mathematical relationship between the characteristic particle size and uniformity coefficient of the RAP material after extraction. The characteristic particle size of the RAP material after extraction reduces, while the uniformity coefficient gets further reduced. With the extension of the age, the characteristic particle size and uniformity coefficient of the mixture have shown a significant linear attenuation. In order to ensure the quality stability of recycled mixtures, the classification and management of RAP materials should be strengthened in the actual recycling design and application process.
Study on the Application of Green Environmental Protection Building Materials in Engineering
Authors: Jialei Wang , Hongmin Li , Weiqiong Liu 
Published: June 2021

Abstract
This paper briefly introduces the significance of applying green environmental protection building materials under the background of serious energy consumption and environmental pollution and the current development situation in China. According to the relevant literature and survey data, three restrictive factors in application of green environmental protection building materials are summarized, and some suggestions are put forward.
Study on technical standard of small complete domestic sewage treatment plant
Authors: Jin Huang , Xiaoxin Zhang , Youfeng Sun , Xia Huang , Guanjun Wang 
Published: June 2021

Abstract
This paper expounds the industry and policy background of small complete domestic sewage treatment plant in China, and discusses the basic principles and basic investigation of the development of technical standard for small complete domestic sewage treatment plant, the key technical contents of standard for small complete domestic sewage treatment plant are expounded. Through the development and implementation of this technical standard, it will provide standardized technical support for standardizing and improving the manufacturing level of small complete domestic sewage treatment plants in China.
Research on the Coordinated Development of Resources, Environment, and Economy in the Yellow River Basin
Authors: Zhao Jinhui , Wang Yufeng , Liu Tao , Dong Yiran , Cao Xinyu , Zhang Ting , Zhang Yu , Zhang Lijun 
Published: June 2021

Abstract
The high-quality development in the Yellow River Basin has to be fostered by the coordination of resources, environment, and economy. Therefore, conducting an analysis on the coupling level of resources, environment, and economy in the Yellow River Basin is of major significance to the research on its high-quality development path. The current study focuses on the coupling coordination in the Yellow River Basin. Based on the data of the nine provinces in the Yellow River Basin from 2004 to 2017, a coupling development model is constructed for an analysis of the coupling level in this area and a modeling prediction. A comprehensive evaluation of the development level of resources-environment-economy system and the subsystems in the Yellow River Basin is performed by combining the range change method and entropy weight method. The result shows that despite the rising coupling level of resources, environment, and economy in the Yellow River Basin, the comprehensive evaluation value of the environment subsystem is low, which was merely 0.109 in 2017 and has remained unchanged between 2009 and 2017, resulting in a low coupling coordination degree of resources, environment, and economy. In 2017, the coupling coordination degree only exceeded 0.4. The development was on the verge of imbalance and the high-quality coordinated development of the Yellow River Basin has been restricted.
Influence of refrigerant circuitry arrangement of three-row finned tube evaporator on heat transfer performance under uniform wind speed distribution
Authors: Wang Xue , Wang Ruoyu , Zhang Yu 
Published: June 2021

Abstract
The EVAP-COND software was used to simulate 8 different refrigerant circuitry of the three-row tube heat exchanger under different superheat and outlet saturation temperature conditions. The influence of different refrigerant circuitry on the heat transfer performance of the evaporator was explored. And the influence of superheat and outlet saturation temperature on the evaporator and its changing law were analyzed and discussed. The results show that: Cross arrangement facilitated heat transfer. The dual-flow solution was better than the single-flow solution. And countercurrent arrangement was conducive to heat exchange. The best solution was g, and the worst solution was a. Under the conditions of this study, the heat transfer of curve g was 44.78% and 36.20% higher than curve a, respectively.
Evaluation System of Ningbo’s Water-saving Society Construction under the Digital Economy
Authors: Zhang Yubin , Zhu Huomei , Huang Danxia , Yu Rui 
Published: June 2021

Abstract
In response to the difficulties and problems in the construction of a water-saving society and the construction of a water-saving society in Ningbo in recent years, with rivers as the main canal, the digital economy water-saving society management model was innovatively proposed, and the evaluation index system for social construction was built in the water-saving society, combined with the connotation of the digital economy, a water-saving society evaluation method was put in Ningbo, and suggestions and countermeasures also referred.
Analysis on Improvement Effect of Water Distribution Parameters on River Water Quality
Authors: Lei Hua , Heqin Shang , Qiannan Jin 
Published: June 2021

Abstract
The parameters, such as hydrological condition of the river, location, distributed approach, quantity and quality of water distribution, cann’t be ignored in improving water qualiy of the river. With Liudu River in Yiwu City as a case study, 1-D water hydrodynamic and water quality model was generated to analyze the effect of water distribution parameters on river water quality. The results showed that, the location and distributed approach of water distribution had little influence on the water quality of the river behind the distribution point. Otherwise, concentrated distribution approach was better than dispersive approach, and upstream distribution was better than downstream distribution. The hydrological condition of the river should be considered in the assessment. With the increase of distribution quantity, the improvement effect of the river water quality was increased gradually, but the effect brought by the unit quantity was obviously decreased, the effect brought by the improvement of water quality standed out increasingly.
Multi-Objective Optimization of Efficiency and Pressure Fluctuation for Vertical Inline Pump
Authors: Chen J W , Wang W J , Pei J 
Published: June 2021

Abstract
Vertical inline pump is a single-stage single-suction centrifugal pump. In order to save the installation space, there is a bent pipe before the impeller. In this paper, to achieve efficient and stable operation of the pump, a multi-objective optimization of efficiency and pressure fluctuation on the inlet pipe of vertical inline pump was proposed based on Latin Hypercube Sampling. The geometric shape of an inlet pipe is controlled by the mid curve and the shape of cross section. The fifth-order Bezier curve was adopted to fit the mid curve and a round cross section was set. Totally 7 design parameters of the inlet pipe were selected as design variables, and the pump efficiency and the pressure fluctuation amplitude at the tongue were set as the optimization objectives. 36 groups of sample points were obtained from Latin hypercube sampling (LHS). The results showed that at design flow rate, the efficiency increased from 77.60% to 79.33%. Comparing with prototype, the pressure fluctuation amplitudes of main frequency at two monitoring points were decreased by 0.89% and 9.15%. It was observed that the profile of inlet pipe has an obvious influence on the pump performance and unsteady flow characteristics. Therefore, the profile of inlet pipe will be the key component for the optimization of vertical inline pump, and this study can provide theoretical guidance for researching the hydraulic efficiency and unsteady pressure fluctuation.
Numerical Analysis of reactor coolant pump performance under reverse conditions
Authors: Ran Hongjuan , Qian Xinru , Shi Tianjiao , Wang Dezhong 
Published: June 2021

Abstract
Since no anti-reverse device is equipped in the system of the third generation AP 1000 of nuclear power plant, the reactor coolant pump (RCP) might operate in the reverse condition. However, it is hard to carry out the experiments of RCP in reverse condition due to its high temperature and special thrust bearing (their thrust bearing may not afford the reverse condition either). Hence, CFX with unsteady RANS turbulence model is employed to thoroughly study the characteristics of the reactor coolant pump in reverse pump mode as well as the normal pump condition. Their different flow patterns between the normal case and the reverse case are compared. It is found that a beat frequency captured in the impeller in the reverse case is suggested to be the diagnostic signal of the generation of reverse condition.
Theoretical Turbine Model with Hydraulic Losses
Authors: Svingen B , Reines A F , Nielsen T K , Storli P T 
Published: June 2021

Abstract
When doing transient and dynamic analysis of powerplants, a mathematical representation of the turbine is needed. These models can be fully based on empirical data, or they can be based on a first principles approach. A first principles approach is practical in many circumstances because any known and unknown turbine can be modelled, and the model can easily be simplified and linearized without losing generality or physical correctness. The model can be used for general transient studies, also where the turbines are not yet specified, or when doing control system analysis and analysis of the grid.
Using the Euler turbine equations together with the definition of the turbine opening degree, one obtains a model that is geometrically and physically correct. The development of this model started several years ago, and this paper presents the current development. The model shows good agreement of the efficiency as a function of speed, as part of the Euler turbine equation. However, the efficiency as a function of flow is over predicted because hydraulic loss phenomenon such as turbulence and dissipation are not inherently included. There are several ways to include the hydraulic losses. This can be done in a simplified manner, or more elaborate, which also could involve empirical relations for exact fit with a measured turbine. This paper discusses these possibilities, along with some examples.
Hydraulic Design Challenges of High Head 880 MW Gouvães Pumped-Storage Power Plant
Authors: Nicolet C , Landry C , Richter W , Vera Rodriguez J C , De la Torre Abietar L , Zenz G 
Published: June 2021

Abstract
The 880 MW pumped-storage power plant of Gouvães, which is part of the Alto Tâmega hydro power scheme from Iberdrola is currently under construction in the north of Portugal. The power plant is equipped with 4 reversible Francis pump-turbines with a gross head of 660 m. The power plant features several challenges with respect to the hydraulic design such as: i) ultra-high-head single stage reversible Francis pump-turbine of very low specific speed leading to severe hydraulic transients, ii) a long high-pressure penstock, iii) an headrace differential surge tank linked to a 4700 meters long headrace tunnel and iv) a complex tailrace differential surge tank linked to a 700 meters long tailrace tunnel. To perform the hydraulic design of the pumped-storage power plant, a stepwise approach presented in the paper was undertaken by Iberdrola. A detailed 1D hydraulic transient analysis was performed to optimize the headrace and tailrace surge tank dimensions. Then a combined CFD and reduced scale physical transient tests of both surge tanks was conducted. This enabled to address the complex 3D flow physics that develop in surge tanks but are not captured by 1D transient simulations such as free surface, upsurges against walls, verification of throttle singular head losses and effects not captured by 3D CFD such as air-water mixture and detection of air entrainment risk.
Application of a General Discrete Adjoint Method for Draft Tube Optimization
Authors: Fleischli B , Del Rio A , Casartelli E , Mangani L , Mullins B F , Devals C , Melot M 
Published: June 2021

Abstract
Automatic optimization is becoming increasingly important in turbomachinery design to improve the performance of machine components and Evolutionary Algorithms (EAs) play a very important role in this task. The main drawback of EAs is the large number of evaluations that are required to obtain an “optimal” result. Consequently, in order to keep the computational time in an affordable frame for design purposes, either the mesh size has to be limited, thus reducing the resolution of the flow phenomena, or the number of free parameters must be kept small. Adjoint optimization does not suffer from these restrictions, i.e. the optimization time is not affected by the number of parameters. The computational effort for the adjoint method scales only with the grid size and is usually in the range of two times the CFD simulation alone. In this paper, a discrete adjoint method based on a coupled pressure based RANS solver is presented and applied to draft tube optimization. The adjoint solver is general and can therefore deal with any turbulence model supported by the CFD solver as well as any boundary condition, including mixing planes and mesh interfaces needed for multi-stage simulations. Furthermore, there is no restriction on the choice of objective function. The adjoint method is first applied to a baseline draft tube geometry and then again to its EA optimized geometry where the objective function was the minimization of losses in the draft tube. To reduce the complexity for this proof of concept but still including multiple operating points in the optimization, only peak efficiency and full-load were optimized simultaneously. The adjoint optimization can significantly improve the draft tube performance in both cases (baseline and EA optimization). The interplay between local and global optimization seems to be a promising strategy to find optimal geometries for multi-operating point/multi-objective optimization and will be further investigated in subsequent research.
Study of Flow Characteristics inside Francis Turbine Draft Tube with Adjustable Guide Vanes
Authors: Joy Jesline , Raisee Mehrdad , Cervantes Michel J. 
Published: June 2021

Abstract
Numerical investigation was performed on a semi-model (one stay vane, two guide vanes, one runner passage inclusive of one main and one splitter blade, and the draft tube) of a high-head Francis turbine model with adjustable guide vanes in the draft tube. The motive of the present study is to investigate the possibility to mitigate the rotating vortex rope (RVR) formed at part load operating condition. Each guide vane in the draft tube consists of two hydrofoils. The upper hydrofoil is adjustable according to the flow angles leaving the runner. The lower hydrofoil is stationary and corresponds to the flow angle at best efficiency point (BEP).The factors considered while designing these guide vanes were a) number of guide vanes, b) chord length, c) span and d) position in the draft tube. The preliminary results indicate that the RVR pressure amplitude was suppressed by 97% compared to the reference model with no guide vanes at part load (PL) operating condition. An 8.7% increment in the draft tube pressure recovery was obtained which indicates that implementation of the guide vanes in the draft tube could positively impact the turbine efficiency beside the mitigation of the pressure pulsations at PL operation.
Particle image velocimetry measurements in the vaneless space of a model Francis turbine under steady state operation
Authors: Sagmo K F , Mærlie A , Storli P T 
Published: June 2021

Abstract
Two-dimensional, two component particle image velocimetry (PIV) measurements of the guide-vane wake and vaneless space for a high head Francis model turbine are presented. Measurements have been carried out with a fixed head and rotational speed for a set of guide-vane openings representative of part load, high load and best efficiency operating points. The measured trajectory and strength of the guide vane wake for the different operating points is discussed in conjunction with the periodic velocity oscillations. It is hoped that the present measurements will aid in further analysis as well as provide an additional set of data for validation of numerical analyses.
Experimental study on load rejection process of a model tubular turbine
Authors: Zhou Daqing , Chen Huixiang , Kan Kan , Yu An , Binama Maxime , Chen Yanan 
Published: June 2021

Abstract
To obtain the dynamic parameters variation characteristics of a model tubular turbine during the load rejection process, a model test method was designed and carried out in this paper. Firstly, the model test system, the test method and the model tubular turbine parameters were introduced. Then, the experiments of different schemes were performed and the results were analyzed. Evidently, the closing rules of guide vanes and runner blades have influence on the quality of transient process. When the guide vanes undergo linear needle closure law, the effect of prolonging the blade closing time on reducing the maximum speed appreciation and the maximum reverse water thrust is obvious, and when the guide vanes is closed in two stages, the longer the blade closing time, the lower the maximum reverse hydraulic thrust value. With the same closing law, the segmental closure law with guide blade first fast and then slow is more obvious than the linear needle closing law in reducing the maximum reverse water thrust, and the selection of closure segment point of guide vanes has a certain effect on the appreciation of the maximum rotating speed. Thus, the model test method could be used in transient operation improvement at hydropower plants.