Page 110 - 2025年第56卷第1期
P. 110

Effects of structural parameters of the injector on sediment erosion
                                             characteristics in a Pelton turbine

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                           LI Chenxi , LI Fang , GUO Pengcheng , SUN Shuaihui , SHEN Peirong
                      (1. Institute of Water Resources and Hydroelectric Engineering, Xi’an University of Technology, Xi’an  710048, China;
                    2. State Key Laboratory of Eco-hydraulics in Northwest Arid Region, Xi’an University of Technology, Xi’an  710048, China)


                  Abstract: Sediment erosion is one of the core problems faced by Pelton turbines, especially when the injector is
                  exposed to high-speed sediment-laden water flow, leading to erosion damage that threatens the safe operation of
                  the turbine. To investigate the erosion characteristics and influence mechanisms of the injector, based on the VOF
                  (Volume of Fluid) model, the Euler-Lagrange method, and the Oka erosion model, an erosion analysis model for
                  the injector is established. Firstly, combining the analysis of internal flow and the trajectory of sediment particles,
                  this paper indicated that the most serious erosion regions are located at the throat of the nozzle and the needle tip.
                  The throat of the nozzle shows flake wear and is affected by the Dean vortex, resulting in a larger inner erosion area.
                  The needle tip shows serious scattered erosion. Then, the nozzle angle, the needle angle, and the diameter of the
                  needle transition section are selected as three key structural parameters of the injector to study the influence mecha⁃
                  nism of erosion characteristics. The results show that these three parameters have different effects on the erosion
                  performance of different regions of the injector. Within a certain range, the erosion degree of the tip increases with
                  the increase in the diameter of the needle transition section. When the transition section diameter increases too close
                  to the needle diameter, the average erosion rate of the tip deteriorates to 9 times the small diameter. With the in⁃
                  crease of the needle angle, the erosion degree of the nozzle throat and the needle tip is improved, and the average
                  erosion rate of the needle tip can be reduced by 94.17%, but the effects of the needle angle on erosion performance
                  and hydraulic performance are mutually inhibitory. With the increase of the nozzle angle, the erosion degree of the
                  needle transition section can be effectively inhibited. Therefore, the design with a larger needle angle, a larger
                  nozzle angle, and a smaller diameter of the spray needle transition section can enhance the erosion resistance at the
                  high erosion zone of the needle tip and reduce the overall erosion range. Meanwhile, it is essential to consider hy⁃
                  draulic performance to ensure the efficient and safe operation of the turbine.
                  Keywords: Pelton turbine; injector; water-air-sand three-phase flow; sediment erosion characteristics; influ⁃
                  ence mechanisms
                                                                                    (责任编辑: 王  婧)

              (上接第 92 页)

                     A legal perspective of deconstruction and reconstruction of water resources concept:
                             Shift from focusing on entities to focusing on functions and services

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                                 LI Jun , ZHANG Baozhong , HU Desheng , XING Yongzhi
                                     (1. Xi’an Jiaotong University School of Law, Xi’an  710049, China;
                                  2. Shaanxi Bureau of National Mining Safety Supervision, Xi’an  710001, China;
                         3. State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, Beijing  100048, China;
                                       4. Chongqing University Law School, Chongqing  400044, China;
                    5. Shanghai Municipal Engineering Design and Research Institute (Group) Co., Ltd. Hefei Branch, Hefei  230031, China)

                  Abstract: To define the concept of water resources accurately and reasonably from a legal perspective, it is nec⁃
                  essary for further clarifying the scope of state ownership of water resources, scientifically calculating the value of
                  water resource assets, deeply researching water rights and promoting the management, protection and reasonable
                  market allocation of water resources. In this paper, the existing explanation of the concept of water resource was
                  analyzed from the aspects of formal logical and real significance combined with the analysis results and the theoret⁃
                  ical perspective of cross integration of natural science and social science, this paper transfers the focus of attention
                  from the water substance to the function and service. Through the analysis of hydrological cycle and its function,
                  the relationship between hydrological cycle and social economic system as well as an analysis of “ natural re⁃
                  sources" which is a superordinate concept of “water resource”, this paper reveals that the essence of “water re⁃
                  sources” lies in the service provided by the natural hydrological cycle provide to social and economic systems. By
                  fully considering the operability of legal concepts, the services provided by the hydrological cycle for the socio-e⁃
                  conomic system, apart from the water substance itself, are integrated into the concept of water resources. Subse⁃
                  quently, a legal expression is given to define the concept of water resource, thereby achieving a higher level of
                  the theoretical generalization of the concept connotation and denotation of water resources.
                  Keywords: water resources; concept; formal logic; hydrological cycles; natural resources
                                                                                    (责任编辑: 韩  昆)

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