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.

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 Flow Fields and Head Losses of Trash-Barriering in Pumping Station Based on VOF Model

2014 ◽  
Author(s):  
Shuquan He ◽  
Baoyun Qiu ◽  
Shiji Chu ◽  
Xiaoli Feng
Keyword(s):  
Numerical Simulation ◽  
Specific Gravity ◽  
Flow Fields ◽  
Head Loss ◽  
Blockage Ratio ◽  
Turbulence Scale ◽  
Head Losses ◽  
Vof Model ◽  
Ansys Cfx ◽  
Simulation And Experiment

In order to calculate flow fields behind the trash rack and the head loss caused by trash-barriering, the waterweed lump congregated in front of the trash rack was simplified as watertight entity that has the same shape and the same size of the waterweed lump. We adopted ANSYS CFX software and VOF method in numerical simulation of the flow fields of trash-barriering, calculated several schemes, and analyzed the influences of blockage. The results show that: the water level difference and the head loss of numerical simulation are consistent with results of experiment. Because of tiny water permeability of the waterweed lump in front of the trash rack, there are nuances between the flow fields behind the trash rack of numerical simulation and experiment. The specific gravity of the waterweeds is less than that of water and the waterweeds block the up part of the trash rack, which makes the flow velocity through the down unblocked part of the trash rack increase rapidly. As a result, the velocity behind the trash rack increases in the lower area, and decreases, even the backflow appears in the upper area. With the increase of the blockage ratio, the turbulence scale behind the trash rack increases. When the blockage ratio increases to 0.7, the velocity uniformity already decreases to −1.57. The head loss of trash-barriering increases when the blockage ratio and the velocity in front of the trash rack increase. For certain velocity in front of the trash rack, when the blockage ratio reaches 0.6∼0.7, the head loss would increase rapidly.

Stabilization of the Speed of the Hydraulic Motor Through Throttle Compensation for Volume Losses

2020 ◽  
Vol 26 (3) ◽  
pp. 126-130
Author(s):  
Krasimir Kalev
Keyword(s):  
Flow Rate ◽  
Hydraulic Drive ◽  
Pressure Change ◽  
Operating Conditions ◽  
Drive System ◽  
Inlet Pressure ◽  
Schematic Diagram ◽  
Hydraulic Characteristics ◽  
Hydraulic Motor ◽  
Flow Through

AbstractA schematic diagram of a hydraulic drive system is provided to stabilize the speed of the working body by compensating for volumetric losses in the hydraulic motor. The diagram shows the inclusion of an originally developed self-adjusting choke whose flow rate in the inlet pressure change range tends to reverse - with increasing pressure the flow through it decreases. Dependent on the hydraulic characteristics of the hydraulic motor and the specific operating conditions.

Numerical Simulation of Gas Flow and Heat Transfer in Cross-Wavy Primary Surface Channel for Microtubine Recuperators

2005 ◽  
Author(s):  
H. X. Liang ◽  
Q. W. Wang ◽  
L. Q. Luo ◽  
Z. P. Feng
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Gas Turbine ◽  
Numerical Study ◽  
High Reliability ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Flow And Heat Transfer ◽  
High Heat Transfer ◽  
The Cross

Three-dimensional numerical simulation was conducted to investigate the flow field and heat transfer performance of the Cross-Wavy Primary Surface (CWPS) recuperators for microturbines. Using high-effective compact recuperators to achieve high thermal efficiency is one of the key techniques in the development of microturbine in recent years. Recuperators need to have minimum volume and weight, high reliability and durability. Most important of all, they need to have high thermal-effectiveness and low pressure-losses so that the gas turbine system can achieve high thermal performances. These requirements have attracted some research efforts in designing and implementing low-cost and compact recuperators for gas turbine engines recently. One of the promising techniques to achieve this goal is the so-called primary surface channels with small hydraulic dimensions. In this paper, we conducted a three-dimensional numerical study of flow and heat transfer for the Cross-Wavy Primary Surface (CWPS) channels with two different geometries. In the CWPS configurations the secondary flow is created by means of curved and interrupted surfaces, which may disturb the thermal boundary layers and thus improve the thermal performances of the channels. To facilitate comparison, we chose the identical hydraulic diameters for the above four CWPS channels. Since our experiments on real recuperators showed that the Reynolds number ranges from 150 to 500 under the operating conditions, we implemented all the simulations under laminar flow situations. By analyzing the correlations of Nusselt numbers and friction factors vs. Reynolds numbers of the four CWPS channels, we found that the CWPS channels have superior and comprehensive thermal performance with high compactness, i.e., high heat transfer area to volume ratio, indicating excellent commercialized application in the compact recuperators.

Design of an Air-Cooled Radial Turbine: Part 1 — Computational Modelling

2018 ◽  
Author(s):  
Yang Zhang ◽  
Tomasz Duda ◽  
James A. Scobie ◽  
Carl M. Sangan ◽  
Colin D. Copeland ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Experimental Testing ◽  
Temperature Drop ◽  
Computational Modelling ◽  
Operating Conditions ◽  
Inlet Temperature ◽  
Topology Optimisation ◽  
Internal Cooling ◽  
Element Analysis ◽  
Radial Turbine

This paper is part of a two-part publication that aims to design, simulate and test an internally air cooled radial turbine. To achieve this, the additive manufacturing process, Selective Laser Melting (SLM), was utilized to allow internal cooling passages within the blades and hub. This is, to the authors’ knowledge, the first publication in the open literature to demonstrate an SLM manufactured, cooled concept applied to a small radial turbine. In this paper, the internally cooled radial turbine was investigated using a Conjugate Heat Transfer (CHT) numerical simulation. Topology Optimisation was also implemented to understand the areas of the wheel that could be used safely for cooling. In addition, the aerodynamic loss and efficiency of the design was compared to a baseline non-cooled wheel. The experimental work is detailed in Part 2 of this two-part publication. Given that the aim was to test the rotor under representative operating conditions, the material properties were provided by the SLM technology collaborator. The boundary conditions for the numerical simulation were derived from the experimental testing where the inlet temperature was set to 1023 K. A polyhedral unstructured mesh made the meshing of internal coolant plenums including the detailed supporting structures possible. The simulation demonstrated that the highest temperature at the blade leading edge was 117 K lower than the uncooled turbine. The coolant mass flow required by turbine was 2.5% of the mainstream flow to achieve this temperature drop. The inertia of the turbine was also reduced by 20% due to the removal of mass required for the internal coolant plenums. The fluid fields in both the coolant channels and downstream of the cooled rotor were analyzed to determine the aerodynamic influence on the temperature distribution. Furthermore, the solid stress distribution inside the rotor was analyzed using Finite Element Analysis (FEA) coupled with the CFD results.

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