Numerical Simulation for Hydraulic Characteristics of MLIS Hydropower Station

2013 ◽  
Vol 353-356 ◽  
pp. 2487-2491 ◽  
Author(s):  
Yuan Ding ◽  
Tong Chun Li ◽  
Min Zhe Zhou
Keyword(s):  
Numerical Simulation ◽  
Surface Water ◽  
Flow Velocity ◽  
Three Dimensional ◽  
Flow Distribution ◽  
Head Loss ◽  
Hydropower Station ◽  
Hydraulic Characteristics ◽  
Multi Level ◽  
Intake Structure

Combined with a multi-level intake structure, using the standard two-equation turbulence model to carry on the three-dimensional numerical simulation for the hydraulic characteristics of this intake .The flow velocity, fluid flow distribution and head loss were analyzed and summarized. The vertical velocity distribution near the intake has been significantly changed after placed stop log gate, the flow velocity of the reservoir surface water near the intake increases significantly, more surface water enter the power plant unit, and the head loss increases greatly.

Numerical Simulation of Hydraulic Shape Optimization for Bifurcated Pipe of Hydropower Station

2012 ◽  
Vol 170-173 ◽  
pp. 3507-3511
Author(s):  
Chang Zhi Ji ◽  
Xu Min Wu ◽  
Jiang Bo Meng ◽  
Jiang Tao Xu ◽  
Wei Bo Chen ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Flow Condition ◽  
Branch Pipe ◽  
Head Loss ◽  
Operating Conditions ◽  
Water Diversion ◽  
Hydropower Station ◽  
Hydraulic Characteristics ◽  
Head Losses ◽  
Shell Type

Steel bifurcated pipe is one important part of the water diversion buildings in a hydropower station. And its hydraulic characteristics are crucial to reduce the head loss of the bifurcated section. The numerical simulation was carried out with spherical trifurcate branch pipe, shell type trifurcate branch pipe without deflecting plates and shell type trifurcate branch pipe with deflecting plates under a serious of operating conditions based on a case study. After this, the flow conditions and the head losses in the bifurcated sections were analyzed. The shell type trifurcate branch pipe with deflecting plates had the most advantageous hydraulic characteristics of the three schemes. The shell type and the deflecting plates improved the flow condition effectively. The scheme could improve the flow condition and reduce the head loss of the bifurcation section effectively. The results might provide some references to the bifurcated pipe design and operation.

Hydraulic Characteristics of the New Type Bulb Turbine With Micro-Head

2013 ◽  
Author(s):  
Lingyu Li ◽  
Yuan Zheng ◽  
Daqing Zhou ◽  
Zihao Mi
Keyword(s):  
Numerical Simulation ◽  
Cfd Simulation ◽  
Guide Vane ◽  
Three Dimensional ◽  
Flow Distribution ◽  
Three Dimensions ◽  
Guide Vanes ◽  
Runner Blade ◽  
Cfd Method ◽  
Bulb Turbine

The head of low-head hydropower stations is generally higher than 2.5m in the world, while micro-head hydropower resources which head is less than 2.5m are also very rich. In the paper, three-dimensional CFD method has been used to simulate flow passage of the micro-head bulb turbine. The design head and unit flow of the turbine was 1m and 3m3/s respectively. With the numerical simulation, the bulb turbine is researched by analyzing external characteristics of the bulb turbine, flow distribution before the runner, pressure distribution of the runner blade surface, and flow distribution of the outlet conduit under three different schemes. The turbine in second scheme was test by manufactured into a physical model. According to the results of numerical simulation and model test, bulb turbine with no guide vane in second scheme has simpler structure, lower cost, and better flow capacity than first scheme, which has traditional multi-guide vanes. Meanwhile, efficiency of second scheme has just little decrease. The results of three dimensions CFD simulation and test results agree well in second scheme, and higher efficiency is up to 77% which has a wider area with the head of 1m. The curved supports in third scheme are combined guide vanes to the fixed supports based on 2nd scheme. By the water circulations flowing along the curved supports which improve energy transformation ability of the runner, the efficiency of the turbine in third scheme is up to 82.6%. Third scheme, which has simpler structure and best performance, is appropriate for the development and utilization of micro-head hydropower resources in plains and oceans.

Hydraulic Performance Optimization on Inlet-Outlet of Pumped Storage Plant

2013 ◽  
Vol 405-408 ◽  
pp. 491-494
Author(s):  
Ya Nan Gao ◽  
Jun Nan Yi ◽  
Rui Cun Zhao ◽  
Li Fen Chen ◽  
Xu Min Wu
Keyword(s):  
Numerical Simulation ◽  
Performance Optimization ◽  
Flow Distribution ◽  
Head Loss ◽  
Hydraulic Performance ◽  
Flow Coefficient ◽  
Head Loss Coefficient ◽  
Uniform Flow Distribution ◽  
Orifice Flow ◽  
Pumped Storage

This paper, using 3-D numerical simulation and the hydraulic model tests, presents an analysis on hydraulic performance of pumped storage plant inlet/outlet. It discusses the uneven flow coefficient, coefficient of orifice flow distribution and head loss coefficient of inlet/outlet in different sizes. The optimized size has a uniform flow distribution, with less to produce unwanted eddies.

Numerical Simulation of Three Dimensional Internal Flow of a PWR Reactor

2016 ◽  
Author(s):  
Jian Ge ◽  
Wenxi Tian ◽  
Tingting Xu ◽  
Jiesheng Min ◽  
Guofei Chen ◽  
...  
Keyword(s):  
Cfd Simulation ◽  
Physical Phenomenon ◽  
Three Dimensional ◽  
Great Influence ◽  
Flow Distribution ◽  
Internal Flow ◽  
Hydraulic Characteristics ◽  
Main Research ◽  
The Core ◽  
Internal Structures

The coolant flow in the reactor pressure vessel (RPV) lower plenum is complex due to the presence of various internal structures, which has a great influence on the flow distribution at the core inlet. In order to study the thermal hydraulic characteristics in the RPV lower plenum, many scaled down test facilities have been built for different PWR reactors such as Juliette, ACOP, and ROCOM. Although the experimental study is still a main research method, it may be not economical in some situations due to the high cost and the long study period. Compared with the experimental method, Computational Fluid Dynamics (CFD) methodology can simulate three dimensional fluid flow in complex geometries and perform parametric studies more easily. The detailed and localized thermal hydraulic characteristics which are difficult to measure during experiments can be obtained. So CFD simulation has been widely used nowadays. One of the purposes of numerical simulations of the internal flow in a RPV is to get the flow distribution at the core inlet, then to make an optimization for the flow diffusor in the RPV lower plenum to improve the core inlet flow distribution homogeneity. Appropriate optimizations for the flow diffusor depends on fully understanding the flow phenomena in the RPV lower plenum. In this paper, Phenomenon Identification and Ranking Table (PIRT) is adopted to analyze the physical phenomenon that occurs in the RPV lower plenum with the typical 900MW reactor internal structures, and the importance of the various physical phenomena and the reference parameters are ranked through expert opinions and literature review. Then a preliminary three dimensional CFD simulation for the reactor vessel is conducted. The main phenomena identified by the PIRT can be observed from the simulation results.

scholarly journals Investigations of Rake and Rib Structures in Sand Traps to Prevent Sediment Transport in Hydropower Plants

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3882
Author(s):  
Mads Mehus Ivarson ◽  
Chirag Trivedi ◽  
Kaspar Vereide
Keyword(s):  
Three Dimensional ◽  
Flow Distribution ◽  
Head Loss ◽  
Total Weight ◽  
Hydropower Plant ◽  
Trap Efficiency ◽  
Hydropower Plants ◽  
Sand Trap ◽  
Sst Turbulence Model ◽  
Three Dimensional Models

In order to increase the lifespan of hydraulic turbines in hydropower plants, it is necessary to minimize damages caused by sediment erosion. One solution is to reduce the amount of sediments by improving the design of sand trap. In the present work, the effects on sand trap efficiency by installing v-shaped rake structures for flow distribution and rib structures for sediment trapping is investigated numerically using the SAS–SST turbulence model. The v-shaped rake structures are located in the diffuser near the inlet of the sand trap, while the ribs cover a section of the bed in the downstream end. Three-dimensional models of the sand trap in Tonstad hydropower plant are created. The present study showed that integrating rib type structure can reduce the total weight of sediments escaping the sand trap by 24.5%, which leads to an improved sand trap efficiency. Consequently, the head loss in the sand trap is increased by 1.8%. By additionally including the v-shaped rakes, the total weight of sediments escaping the sand trap is instead increased by 48.5%, thus worsening the sand trap efficiency. This increases head loss by 12.7%. The results also show that turbulent flow commencing at the sand trap diffuser prevents the downstream settling of sediments with a diameter of less than one millimeter. The hydraulic representation of the numerical model is validated by comparison with particle image velocimetry measurements of the flow field from scale experiments and ADCP measurements from the prototype. The tested rib design has not previously been installed in a hydropower plant, and can be recommended. The tested v-shaped rakes have been installed in existing hydropower plants, but this practice should be reconsidered.

Numerical Simulation and Model Test on Hydraulic Characteristics of Long-Distance Inverted Siphon

2012 ◽  
Vol 212-213 ◽  
pp. 1131-1135 ◽  
Author(s):  
Juan Li ◽  
Zhen Wei Mu ◽  
Lin Li
Keyword(s):  
Numerical Simulation ◽  
Model Test ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Inlet Section ◽  
Hydraulic Characteristics ◽  
Filling Process ◽  
Long Distance ◽  
Three Dimensional Flow ◽  
Inverted Siphon

Make Use of three-dimensional flow field turbulence numerical simulation of unsteady flow k~εturbulence model and tracking the free surface VOF method of long-distance inverted siphon. By numerical calculation of flow characteristics and pressure distribution, carried out with the model test contrast, the results were coordinate and meet the requirements of design. But vortex formed in the filling process, it is recommended to optimize the inverted siphon inlet section. The method of combining calculation and test on the long-distance inverted siphon provide the reference for the design and operation.

Analysis and Numerical Simulation of Leakage Flow of Low Speed High Torque Water Hydraulic Motor’s Plain Flow Distribution Pair

2012 ◽  
Vol 233 ◽  
pp. 204-207 ◽  
Author(s):  
Zhi Qiang Wang ◽  
Dian Rong Gao ◽  
Jia Huan Fei
Keyword(s):  
Numerical Simulation ◽  
Flow Velocity ◽  
Flow Distribution ◽  
Maximum Flow ◽  
Leakage Flow ◽  
Hydraulic Motor ◽  
Low Speed ◽  
Water Hydraulic ◽  
The Relationship ◽  
Maximum Flow Velocity

In order to ensure volumetric efficiency of low-speed and heavy-torque water hydraulic motor, the relationship between leakage flow and clearance of motor’s plain flow distribution pair in which water is used as medium is analyzed, and it’s concluded that the clearance of port plate and rotor end should be controlled below 5μm. In addition, the port plate flow field was simulated by using CFD software, and got that the leakage flow of numerical simulation is greater than theoretical calculation, and the numerical simulation values are more credible. It is also found that the maximum flow velocity is 16 m/s when outer ring is working, and when inner ring is working the maximum flow velocity is 20 m/s.

Numerical Simulation of Flow Distribution in the Lower Plenum of NHR200-II

2017 ◽  
Author(s):  
Wei Li ◽  
Dingqu Wang ◽  
Yueyuan Jiang ◽  
Songyang Li ◽  
Wenli Guo ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Three Dimensional ◽  
Flow Distribution ◽  
Flow Channel ◽  
Outlet Temperature ◽  
Three Dimensional Model ◽  
Support Structure ◽  
Pressurized Water ◽  
The Core ◽  
Set Up

The type-II 200MW nuclear heating reactor (NHR200-II) designed by Tsinghua University is a novel pressurized water reactor, whose main specifications are as follows, the heat power is 200 MW, the design pressure of major loop is 10 MPa, the inlet and outlet temperature of coolant are 230 °C and 278 °C. In this paper, a quarter three-dimensional model of the lower plenum of the reactor pressure vessel is set up for analysis. The flow velocity distribution and the pressure distribution on the core supporting structure are calculated by method of three-dimensional numerical simulation. The results show that the lower part of the core produce symmetric vortex due to the existence of support structure. The production of the symmetric vortex, to some extent, increases the instability of the flow. On the other hand, the existence of the vortex is good for uniformity of flow distribution in the outlet holes. The flow rate in the flow channel of support structure is lower at the center and larger in the margin of core inlet. The results show that the maximum of the velocity in the flow channel is 5% higher than the minimum one.

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