scholarly journals Study on Selection of Pressure Regulating Valve for Hydropower Station with Both Surge Tank and Pressure Regulating Valve

2018 ◽  
Vol 246 ◽  
pp. 01033
Author(s):  
Tianchi Zhou ◽  
Gaohui Li ◽  
Yimin Chen
Keyword(s):  
Transient Process ◽  
Maximum Flow ◽  
Hydropower Station ◽  
Surge Tank ◽  
Calculation Results ◽  
Practical Engineering ◽  
Spiral Case ◽  
Unit Speed ◽  
Working Principle ◽  
Selection Of

The transient process in the hydropower station with both surge tank and pressure regulating valve is quite complicated and also critical to operation safety. According to the pressure regulating valve working principle, the influence of the valve diameter on the unit speed and spiral case pressure was analyzed theoretically. Mathematical models of the surge tank and pressure regulating valve in the hydropower station were established based on the characteristic method. In a practical engineering, numerical simulation of large fluctuation and hydraulic disturbance transient process are conducted, verifying the correctness of the theoretical analysis. Based on the calculation results, three principles for selecting the valve diameter are concluded: first, making sure the unit speed meet the regulating guarantee requirements when guide vanes fast close; second, the maximum spiral case pressure of two times should be approximate to each other by controlling the superposition of surge wave and water hammer; third, the maximum flow of the valve should be as close to the rated flow of the turbine as possible. The principles are helpful for selecting the valve diameter in similar hydropower station.

scholarly journals Hydraulic Transients in the Long Diversion-Type Hydropower Station with a Complex Differential Surge Tank

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Xiaodong Yu ◽  
Jian Zhang ◽  
Ling Zhou
Keyword(s):  
Pressure Difference ◽  
Mathematic Model ◽  
Hydropower Station ◽  
Maximum Pressure ◽  
Surge Tank ◽  
Hydraulic Transients ◽  
Rotating Speed ◽  
Spiral Case ◽  
Two Sides ◽  
Breast Wall

Based on the theory of hydraulic transients and the method of characteristics (MOC), a mathematic model of the differential surge tank with pressure-reduction orifices (PROs) and overflow weirs for transient calculation is proposed. The numerical model of hydraulic transients is established using the data of a practical hydropower station; and the probable transients are simulated. The results show that successive load rejection is critical for calculating the maximum pressure in spiral case and the maximum rotating speed of runner when the bifurcated pipe is converging under the surge tank in a diversion-type hydropower station; the pressure difference between two sides of breast wall is large during transient conditions, and it would be more serious when simultaneous load rejections happen after load acceptance; the reasonable arrangement of PROs on breast wall can effectively decrease the pressure difference.

Research on Reinforcement of Spiral Case during Capacity-Increasing Improvement for Gezhouba Hydropower Station

2012 ◽  
Vol 170-173 ◽  
pp. 2089-2094
Author(s):  
Xian Jun Wang
Keyword(s):  
Working Conditions ◽  
Three Dimensional ◽  
Hydropower Station ◽  
Calculation Results ◽  
Spiral Case ◽  
Stress And Deformation

The stress and deformation of spiral case of Gezhouba Hydropower Station under three working conditions such as before the capacity-increasing improvement, during the disassembly of the spiral case and after the capacity-increasing improvement are calculated by three dimensional FEM..the reinforcement plan of spiral case is proposed based on the above calculation results and also analyzed by three dimensional FEM. Study on the results of different working conditions mentioned above shows that the unit disassembly scheme is feasible and the reinforcement plan is effective.

Influence of Successive Load Rejections on Water Hammer Pressure of Spiral Case in Long Diversion-Type Hydropower Station

2014 ◽  
Vol 607 ◽  
pp. 551-555 ◽  
Author(s):  
Xiao Dong Yu ◽  
Jian Zhang ◽  
Cheng Yu Fan
Keyword(s):  
Numerical Model ◽  
Method Of Characteristics ◽  
Water Hammer ◽  
Hydropower Station ◽  
Maximum Pressure ◽  
Surge Tank ◽  
Hydraulic Transients ◽  
Rotating Speed ◽  
Spiral Case

Based on the theory of hydraulic transients and method of characteristics (MOC), the numerical model of hydraulic transients in water way system was established using the data of a practical hydropower station, and the probable transients were simulated. The influence of successive load rejection conditions on water hammer pressure of spiral case was analyzed. Compared with simultaneous load rejection, successive load rejection can make maximum pressure in spiral case and maximum rotating speed of runner more serious if the bifurcated pipe converging under surge tank in diversion-type hydropower station.

Mechanism of air-trapped vertical vortices in long-corridor-shaped surge tank of hydropower station and their elimination

2017 ◽  
Vol 29 (5) ◽  
pp. 845-853 ◽  
Author(s):  
Fang Cai ◽  
Yong-guang Cheng ◽  
Lin-sheng Xia ◽  
Yong-qi Jiang
Keyword(s):  
Hydropower Station ◽  
Surge Tank

Research and Application of High-Efficiency Multi-Cyclone Dust Removal

2011 ◽  
Vol 109 ◽  
pp. 400-404
Author(s):  
Yan Hong Yang ◽  
Da Fu Ni
Keyword(s):  
Structural Design ◽  
High Efficiency ◽  
Dust Removal ◽  
Working Principle ◽  
Selection Of

Performance and working principle of high-efficiency multi-cyclone were analyzed, and the structural design shortage of original high-efficiency multi-cyclone was pointed out. Its structure was researched and designed, including determination of setting chamber and pipe number, selection of material and the design of cyclones.

Numerical Simulation on Rupture Behavior and Selection of Safety Membranes

2014 ◽  
Author(s):  
Chen Sheng ◽  
Zhang Jian ◽  
Xiaodong Yu
Keyword(s):  
Present Theory ◽  
Large Fluctuation ◽  
Surge Tank ◽  
Small Hydropower ◽  
Weak Points ◽  
Maximum Water ◽  
Safety Operation ◽  
Hydropower Stations ◽  
Selection Of ◽  
Rupture Behavior

This present study deals with a new mechanical device consisting of a set of safety membranes, which has been successfully applied in several middle and small hydropower stations in China instead of a surge tank. Safety membranes are installed on the penstock near the powerhouse as controlled weak points. When the pressure caused by load rejection rises to the preset explosive value, one or more membranes rupture, protecting the penstock and the unit from damage. The device is simple, reliable and economical. The method of characteristics is employed to establish numerical model of safety membranes to simulate their rupture behavior, which is then introduced to investigate how to determine the number and diameter of membranes from two aspects, large fluctuation and hydraulic disturbance. The results show that the diameter of the membranes depends on the negative pressure along pipeline under hydraulic disturbance while the number of the membrane depends on the maximum water hammer pressure under large fluctuation during load rejection of the unit. The conclusion of membrane selection can perfect the present theory of safety membranes, and provide the theoretical guidance and practical basis for membrane device design and safety operation.

PREDIKSI PENERIMAAN KARYAWAN BAGIAN DESAIN PADA EVENT ORGANIZER PT. SEIRAH WISATA MENGGUNAKAN ALGORITMA C4.5

2021 ◽  
Vol 5 (1) ◽  
pp. 28-32
Author(s):  
Hendriyanto , Bei harira
Keyword(s):  
Human Resources ◽  
Extensive Experience ◽  
Gain Ratio ◽  
Vital Part ◽  
C4.5 Algorithm ◽  
Calculation Results ◽  
Selection Of

ABSTRACT Human resources design section at an Event Organizer is a vital part considering that the design will be seen by the event participants in addition to the technical events. The selection of employees who understand design and have extensive experience is important. The process of selecting employees in the design field can sometimes be difficult to predict if there are several prospective employees with balanced abilities. From the calculation results of the dataset as many as 14 applicants using the C4.5 algorithm, the highest Gain Ratio value obtained in the design Ability and Experience = 0.7172, Origin of Schools = 0.0511 and Age = 0.0205. Keywords : event organizer, C4.5 algorithm, prospective employees, Gain Ratio

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