bluuebunny/crossref_metadata_2025_split huggingface dataset:
Aerodynamic design and optimization analysis of a 200 kW radial-inflow turbine
Authors: Wan Bochen , Zheng Wang , Zhang Zhen , Si Qiaorui 
Published: October 2024

Abstract
In low-temperature waste heat recovery for organic Rankine cycle (ORC) power generation, the radial-inflow turbine (RIT) plays a crucial role. This study focuses on the preliminary design, three-dimensional simulations, and optimization of a 200 kW RIT for R245fa working fluid. The turbine’s preliminary design relies on selected empirical coefficients, leading to performance uncertainty. The performance of the turbine obtained from the initial design was evaluated using computer simulations, indicating that achieving outstanding isentropic efficiency and power targets solely relying on the design of empirical coefficients can sometimes be challenging. Design of Experiments (DOE) on five variables was performed using the Isight platform, highlighting rotor inlet blade height as crucial for turbine performance. The optimized RIT showed a 10.5% efficiency increase and 45.6 kW power gain. Entropy production analysis confirmed substantial improvement. Systematic theoretical calculations followed by DOE optimization effectively enhance turbine efficiency, providing valuable and innovative insights for satisfactory design solutions.
Analysis of safety margin for pump-turbine “S” characteristics of Pumped-storage Power Stations
Authors: Xiao Wei , Liu Dianhai 
Published: October 2024

Abstract
The pump-turbine is the “heart” of Pumped-storage Power Stations, and the “S” characteristics is an inherent characteristic of the routine Francis pump-turbine unit, which is an important factor affecting the safe and stable operation of the unit. There are three main methods for conducting research on the “S” characteristics: model testing, on-site testing, and CFD numerical simulation calculation. Based on the theoretical research of CFD numerical simulation calculation, this article compares and analyzes the results of model testing and on-site testing for specific practical cases, studies the differences between these two methods, and provides suggestions for the reasonable value of safety margin in the “S” area of the pump-turbine based on engineering practice, providing reference for the design of new or renovated power stations and the hydraulic optimization of pump-turbines.
Investigation on the hydraulic loss in the vertical inlet and outlet of a pumped storage power station
Authors: Guo Miao , Wang Zhiheng , Song Ruixiang , Xu Guibin , Wang Wei , Shen Yan 
Published: October 2024

Abstract
The vertical inlet/outlet is commonly adopted in the upper reservoir of pumped-storage power stations, in which the internal flow patterns exert a critical influence on the safety and operational efficiency of the entire power station. Based on the standard k-ε turbulence model coupled with the revised wall roughness theory, this investigation presented a numerical model of a vertical inlet/outlet in a pumped-storage upper reservoir and the validity and accuracy of the numerical simulation are validated through comparison well with the results of the model experiments. The results suggest that the emergence of vortices of varying intensities near the inlet during power-generation scenarios at dead water levels and at 3.5 times of the rated flow rate (389.6 m3/s). The bend section experiences fairly nonuniform flow velocity, with the highest average flow hydraulic loss in the entire vertical pipe inlet/outlet system. These insights provide a substantial utility for operational strategies and optimization designs in related engineering projects.
Design and Performance study of Francis turbine for high head applications.
Authors: Shrestha Kushal , Bijukchhe Pawan Lal , Neopane Hari Prasad , Chitrakar Sailesh , Thapa Bhola 
Published: October 2024

Abstract
Francis Turbines are widely employed globally for their adaptability and operational versatility across a broad range of water flow rates and pressure heads. This study explores the design and optimization of a Francis turbine configured for exceptionally high heads, specifically targeting a design head of 700 m. Traditionally, Pelton turbines are favoured for such high heads, but this study investigates the viability of Francis turbines in this range. Through comprehensive testing, including the development of hill chart diagrams to evaluate performance under various conditions, the study demonstrates promising efficiency levels. Utilizing a simplified approach, the design process involves empirical relations and the Khoj program, resulting in turbine designs representing three different speed numbers: 0.32, 0.42, and 0.52. Efficiency and sediment erosion rates were computed for each and compared between the three designs. The comparison indicates that while the turbine with a speed number of 0.32 exhibits lower efficiency, it offers superior erosion resistivity. Conversely, turbines with speed numbers 0.42 or 0.52 show better efficiency, especially in handling fluctuations in operating conditions. The findings suggest a balance between efficiency and erosion resistivity, recommending the turbine designed for a speed number of 0.32 for superior erosion resistance, and the turbine with a speed number of 0.42 for greater efficiency and operational range. This study broadens the horizon for Francis turbines in high-head applications, offering insights into their potential and viability in extreme conditions.
Research on Optimal Control Strategy for Hydroelectric Units Based on Generalized Smith Predictor and Shortest Time Control
Authors: Qi Guoyang , Luo Xingqi , Men Chuangshe , Li Chenhao 
Published: October 2024

Abstract
At present, most hydroelectric unit controllers use PID speed controllers. The principle of PID control is simple and the technology is mature, but there is less consideration for the need for deep participation of the unit in power grid regulation, resulting in a decrease in regulation quality and even instability of the regulation process when the unit deviates from the design operating conditions, which is difficult to meet the requirements of fast response and high-precision operation of the unit in the new power grid. This article proposes a new control strategy based on the generalized Smith predictor and the shortest time control. Through simulation comparison of the dynamic characteristics of the new control strategy and the conventional PID controller, the results show that the proposed new control strategy has better dynamic characteristics and control accuracy.
Study on the dynamic characteristics of the head cover-bolts-stay ring of a variable-speed pump-turbine
Authors: Yu Shuang , Wang Lei , Wang Zhengwei , Ding Sen 
Published: October 2024

Abstract
The design and operation of variable-speed pump-turbine units is more difficult than that of conventional units due to their adjustable speed, frequent start stop, and forward and reverse operation. Due to the development of variable-speed pump-turbines towards variable-speed, high head, and large capacity, the vibration instability caused by frequent switching between turbine and pump operating conditions is more prominent. The study on the dynamic characteristics of the head cover-bolts-stay ring system is an important guarantee for the long-term safe and stable operation of the units. This article uses the finite element method to conduct modal analysis on the head cover-bolts-stay ring system of a variable-speed pump-turbine. The natural frequency and mode shape are analyzed, and resonance analysis is carried out in combination with the dynamic and static interference characteristics of the variable-speed unit. The research results show that the dynamic and static interference frequency of the unit during the variable-speed process may be close to the natural frequency of the head cover-bolts-stay ring system, which needs to be paid attention to during operation. The results and findings in this article provide theory and practical basis for the research and design of high head, large capacity, and variable-speed pump-turbine units.
Study on the dynamic response behaviour of the head cover-bolts-stay ring of a variable-speed pump-turbine
Authors: Wang Lei , Wang Zhengwei , Yang Shengrui , Yu Shuang , Wei Zichao 
Published: October 2024

Abstract
The vibration characteristics of the hydro-turbine’s head cover is a significant factor that affects the safety of the unit. This paper established the Finite Element Method (FEM) model for the head cover-bolts-stay ring system of a variable-speed pump-turbine, and the dynamic response behaviour of the system under pretension and hydraulic excitation conditions is analyzed. The results indicate that the maximum value of stress locates at the bolt root, which is 715.6MPa under pretension load and 678.7MPa under hydraulic excitation. The results presented in this paper offer valuable guidance for the safety and stability of the variable-speed pump-turbine.
Research on the clearance evolution of preloading filling spiral case and surrounding concrete
Authors: Lu Zhaohui , Luo Yutong , Zhang Zhenwei , Wang Zhengwei 
Published: October 2024

Abstract
The embedment of steel spiral cases within concrete under a pressurized condition is a kind of construction approach that widely used in pump-turbines. There will be an initial preloading clearance between the spiral case and surrounding concrete after the construction. The clearance is directly determined by the preloading water head and changes with the variation in operational hydraulic pressure, which will effect the combined load transmission mechanism. This paper investigates the clearance evolution of preloading filling spiral cases and surrounding concrete under different internal pressure. The effect of the preloading water head on the initial clearance, the contact characteristics and the combined load transmission mechanism under different internal pressure are numerically studied. The results show that the initial clearance between the spiral case and concrete increases with the rise of the preloading water head. The maximum clearances are all located at the waist of the spiral case. The clearance during operation presents uneven distribution characteristics in spatial and temporal scales. Before the internal water pressure comes to the preloading water head, the inlet, outer part in the direction of 45° and the sectional area are the first to close, the outer part of the waist follows, while the outer area of the spiral case middle remains open when the pressure reaches the preloading water head. The contact pressure distribution is consistent with the contact status characteristic. The conclusion of this paper aims to improve the understanding of the effect of the clearance between the preloading filling spiral case and concrete, so as to provide theoretical reference for safe and stable operation of pump-turbine units.
Pressure pulsation and radial force characteristics of dual-side impellers for the turbine energy recovery integrated machine
Authors: Wang Shenghui , Liu Jun , Luo Xianwu , Xiao Yexiang , Zhou Chong , Tian Xiugui 
Published: October 2024

Abstract
The inherent instabilities within the structure of the turbine-type energy recovery integrated machine (TT-ERIM) have the potential to compromise its smoothness and longevity, which could result in malfunctions. The dynamics of the dual-side impeller of TT-ERIM have been investigated through the use of computational fluid dynamics software (CFX) and the manipulation of the inlet flow rate. Pressure pulsation and radial force on each side under different flow conditions, and their impact on the hydraulic performance of the impeller and volute, are compared and evaluated through unsteady numerical calculations. The results show that the pressure fluctuation pattern of a centrifugal pump impeller is suboptimal at low flow rates, with fluctuations increasing as the flow rate falls below the rated value. Conversely, the pressure fluctuations of the turbine impeller remain consistent and are slightly reduced with excessively high flow rates. The generation of a negative pressure zone in the turbine impeller is indicative of an uneven overall pressure distribution. This research provides a theoretical framework for enhancing the TT-ERIM operational stability.
Investigation of mechanical performance for tricuspid valve stent in different compression modes
Authors: Fang Wenhao , Zeng Yongshun , Xu Zhonghua , Zhang Mingkui , Zhang Fengzhi , Luo Xianwu 
Published: October 2024

Abstract
The tricuspid acting as a one-way valve between the right atrium and the right ventricle of the human heart, is very important for the blood circulation system. The regurgitation will be induced if the tricuspid cannot close normally, leading to symptoms such as arrhythmia and right heart failure. In the case of severe regurgitation, replacement with an artificial tricuspid valve instead of the natural tricuspid is the promising solution. For the typical artificial tricuspid valve, the bioprosthesis valve is fixed on a tricuspid valve stent which is usually compressed before being implanted into the heart. In this study, numerical simulation with an ABAQUS standard approach is carried out with a focus on the compression process of the tricuspid valve stent to evaluate the mechanical performances of two compression methods: one is the traditional radial compression method (RCM), and another is the axial compression method (ACM) that gradually compresses through a conical channel. The results indicate that the environment temperature is closely related to the stress distribution for both the RCM and ACM, in particular, a lower temperature can result in lower stress. The maximum strain is located at the inner corner of the joint of the stent ribs and the connection between the top arm and the stent, with a value over 12% at the temperature of 0°C, indicating the possible position for failure. The average diameter-stress curves of the RCM and ACM are respectively obtained for the compression process. To achieve long operation time, the RCM is recommended from the perspective of reducing compressive stress. The present study can provide the experience for the production and clinical application of tricuspid valve stents.
Safe-Enhanced Autonomous Driving Technology Using Conformal Prediction Results
Authors: Liang Jinhao , Fang Ruiqi , Fang Zhenwu , Yan Longhao , Tan Chaopeng , Tian Qingyun 
Published: October 2024

Abstract
Autonomous driving technology significantly improves road safety, mitigates traffic congestion, and paves the way for a more efficient and connected transportation future. However, the uncertain driving scenarios poses a great challenge to the safe control of autonomous vehicles (AVs). Therefore, this paper proposes an enhanced safety control framework by integrating the quantified prediction results of human driving behaviors into the path-planning process. First, a Long Short-Term Memory (LSTM) network is employed for driver behavior prediction, based on which, the conformal prediction, a mathematical statistical method, is introduced to quantify the uncertainties of the prediction results with a probabilistic presentation. Then, a model predictive model controller (MPC) is designed to enable the path-planning ability. By using the Lipschitz constant, the inequality for obstacle avoidance is reformulated as a hard constraint in the MPC optimization framework while considering the conformal prediction results. Finally, some simulation test cases are conducted to validate the proposed method. The results demonstrate the effectiveness to guarantee the safety of AVs with uncertain prediction results.
Meta-Analysis on the Impact of Different Channel Loads on Takeover Performance in Autonomous Driving under Non-Driving Tasks
Authors: Yao Mingxi , Fang Zhenwu , Zhou Xiaozhou , Wang Jinxiang , Yin Guodong 
Published: October 2024

Abstract
Under conditions of high automation, drivers’ excessive engagement in non-driving related tasks can severely impact their takeover ability, posing a significant threat to road safety. Therefore, it’s essential to explore the channel resources occupied by non-driving related tasks to enhance driving safety. However, many studies have merely categorized different types of tasks in experiments without clarifying the relationship between the tasks and the channel resources they occupy. To determine whether different channel loads under non-driving related tasks have varying impacts on autonomous driving takeover performance, a meta-analysis was conducted on literature retrieved from January 2021 to January 2024. The results indicate that tasks occupying visual, auditory, motor, and cognitive channel resources during takeover all affect takeover performance. Among these, cognitive channel resource occupation significantly reduces takeover efficiency, followed by motor and auditory channels, with the visual channel having the least impact.
Classification of high-resolution remote sensing images based on interval type-2 fuzzy logic system
Authors: Wang Chunyan , Gao Peng 
Published: October 2024

Abstract
Aiming at the complexity and uncertainty of remote sensing image classification, this paper proposes a high-resolution remote sensing image classification method based on Interval type-2 Fuzzy Logic Systems for Remote Sensing (IT2FLS-RS), which focuses on dealing with multiple uncertainties and aims to improve the accuracy and reliability of remote sensing image classification. The method establishes a more complex interval two-type fuzzy system covering two types of fuzzifiers, a rule base and an inference machine, and finally uses an integrated algorithm as a defuzzifier to achieve accurate pixel-level classification. In addition, the model uses Constrained Optimization BY Linear Approximations (COBYLA) to optimise the key parameters. In the DLRSD dataset, the accuracy of this model is improved by about 20%, 14%, 24% and 10% compared to the state-of-the-art interval two-type fuzzy neural network algorithm and the benchmark model XGBoost, respectively. On the WHDLD dataset, the accuracy of the proposed method is improved by about 12% and 10% compared to the state-of-the-art interval type-2 fuzzy neural network algorithm and the benchmark model XGBoost, respectively. The experimental results confirm the robustness of the proposed method in processing high-resolution remote sensing image classification, especially the excellent adaptability and scalability in complex feature scenes.
Remote sensing retrieval of surface soil moisture in Mu Us Sandy Land based on optical trapezoid model
Authors: Wang Sinan , Wu Yingjie , Wang Fuqiang , Li Mingyang , Li Wei , Chen Zexun 
Published: October 2024

Abstract
Maowuosu sandland ecosystem is fragile, and moisture is a key factor restricting the growth and development of sandland plants and ecological construction in semi-arid areas. Therefore, this study constructed the eigenspace based on the data of the 4th period of 2016, fitted the dry and wet edge equations of the eigenspace, calculated the OPTRAM, and utilized the measured in situ soil moisture data from various depths during the corresponding period. The OPTRAM was regressed to construct a model for estimating soil moisture. This model was then subjected to a series of validation procedures to ensure its accuracy. The coefficients for the shortwave infrarouges conversion reflection coefficient (STR) - standardized differential vegetation index (NDVI) feature space dry and wet edge fits increased with the increase of the month, where the dry and the R2 for the wet side in September was 0.88 and 0.87, respectively. OPTRAM and the measured soil moisture content data in the surface layer were all correlated to some extent, with correlation coefficients above 0.45. The OPTRAM model is more accurate than other models in inverting in situ moisture content at the 0∼10 cm depths within this area.
Research and application of 3D spatial safety electronic fence technology based on beidou high-precision positioning in substation construction projects
Authors: Zhang Chengwei , Huang Xin , Chen Binqian 
Published: October 2024

Abstract
In recent years, the Beidou Navigation Satellite System (BDS) has developed rapidly, achieving global coverage and being widely used in various fields. The high-precision positioning capability of the Beidou system provides strong technical support for a variety of application scenarios, especially in fields requiring high-accuracy location information, such as safety monitoring in substation engineering. Substations are critical components of the power system, and their operational safety is vital for the stable operation of the entire grid. However, due to the complexity of the equipment and harsh working environments in substation engineering, utilizing Beidou’s high-precision positioning capabilities can significantly enhance the safety management level of substation construction projects and reduce the occurrence of accidents. This paper primarily explores and investigates high-precision positioning-based three-dimensional (3D) spatial safety electronic fence technology for substation construction projects. The process begins with using laser radar to capture 3D scene information and extract key parts of the point cloud model. Comprehensive positioning sensors, integrating the Beidou Navigation Satellite System (BDS) and inertial navigation, are then installed on crane booms to achieve real-time monitoring of the boom’s posture. Finally, a software platform is established to calculate the real-time 3D spatial distance between the crane boom and surrounding sensitive facilities, ensuring the safety of large-scale construction machinery. Field test results validate the effectiveness of the proposed method.
A coupled multi-factor synergistic graph network model for traffic prediction
Authors: Zhong Hua , Chen Cai , Li Dong , Wang Jian 
Published: October 2024

Abstract
Since only the spatio-temporal structure itself is considered in the current traffic prediction process, and there is a lack of multi-factor information about the scene, which leads to problems such as lack of universality and authenticity in the spatio-temporal scene, we proposed a coupled multi-factor synergistic graph network (CM-SGN). For this network, this paper firstly adopts a fusion mechanism to fuse traffic features with coupled scene features, constructs a complex feature correlation matrix, and enhances the multi-feature fusion effect of spatio-temporal scenes; secondly, it introduces a spatio-temporal feature network constrained by an attention mechanism to ensure the spatio-temporal stability of the fused features; and lastly, it reduces the sensitivity of the scene-traffic interdependent targets by using the regression layer combinations of the loss function to improve the prediction generalization capability. Experiments were conducted on two real datasets. Experiments were conducted on two real datasets, and the results show that the model proposed in this paper meets the complex spatio-temporal scenarios in traffic prediction, effectively captures the intrinsic spatio-temporal dependencies, and has good stability and generalization ability.