Comparison of computed water hammer pressures with test results for the Çatalan power plant in Turkey

2004 ◽  
Vol 31 (1) ◽  
pp. 78-85 ◽  
Author(s):  
Bülent Selek ◽  
M Salih Kirkgöz ◽  
Zeliha Selek
Keyword(s):  
Power Plant ◽  
Method Of Characteristics ◽  
Water Hammer ◽  
Francis Turbine ◽  
Test Results ◽  
Transient Pressure ◽  
Governing Equations ◽  
Test Procedures ◽  
Conservation Of Momentum ◽  
Pressure Water

The closure of a flow control mechanism at the end of a penstock may cause significant transient pressures. The governing equations of this unsteady flow phenomenon, the conservation of mass and conservation of momentum, are solved by the method of characteristics using various computational schemes. A study was carried out to compare the computational results of the transient pressures with measured prototype data for the Çatalan Power Plant in Turkey. Prototype data were collected during the closure of the wicket gates of a Francis turbine from the test procedures of "load rejection", "emergency shut down", and "quick stop". The numerical results for the transient pressures just upstream of the turbine are compared with the measured data. The general agreement between the theoretical and experimental results is found to be quite reasonable.Key words: transient pressure, water hammer, power plant, Francis turbine, penstock, method of characteristics.

Numerical Simulation and Analysis of Hydraulic Excitation System Based on Water Hammer by the Method of Characteristics

2011 ◽  
Vol 295-297 ◽  
pp. 2210-2215 ◽  
Author(s):  
Hui Xian Zhang ◽  
Zi Ming Kou ◽  
Juan Wu ◽  
Chun Yue Lu
Keyword(s):  
Numerical Simulation ◽  
Method Of Characteristics ◽  
Experimental System ◽  
Water Hammer ◽  
Vibration Exciter ◽  
Transient Pressure ◽  
Excitation System ◽  
The Method Of Characteristics ◽  
System Pressure ◽  
Excitation Pressure

To study artificially produced and actively controlled water hammer wave caused by hydraulic vibration exciter, a mathematical model was established and an experimental system was designed to verify it. Through the given partial differential equations, a computer code based on the method of characteristics was developed to calculate transient pressure distributed along the pipe under different rotational frequency of vibration exciter. The numerical simulation indicates that there is a simple harmonic vibration rising at the cross sections along the pipe, corresponding to different excitation pressure at every cross section. In addition, the excitation pressure can also be adjusted by system pressure via overflow valve. So, this work is expected to serve for the optimum design of the hydraulic excitation system and play a theoretical guiding role to experimental research in future.

scholarly journals Surge Tank Analysis for Water Hammer Remedy for Long Distance Pipeline

2018 ◽  
Vol 11 (3) ◽  
pp. 47-53
Author(s):  
Nisreen J. Rasheed
Keyword(s):  
Friction Factor ◽  
Method Of Characteristics ◽  
Transient Flow ◽  
Water Hammer ◽  
Pipeline System ◽  
Surge Tank ◽  
Governing Equations ◽  
Long Distance ◽  
Several Variables ◽  
The Impact

Various protection methods can be used for protecting the pipeline system from the impact of water hammer. Which includes the use of special materials for supporting the pipeline and the installation of special devices such as surge tanks, relief valves, and air chambers. In this study, to protect the pipeline system and reduce the effect of water hammer, surge tank has been used. Governing equations of transient flow with and without surge tank is numerically simulated using MATLAB software. Sensitivity analysis was investigated using several variables such as pipe diameter, wave’s velocity and friction factor. Method of characteristics (MOC) was implemented in this study. It was found that the diameter and friction factor of pipe have a significant impact on the results of transient flow and surge tank compared to the effect of wave’s velocity. It has been reached that the capacities of surge tanks at diameter (1m), are (1475m3) at first, second and fourth stages, (1360m3) at third and fifth stages and (570m3) at sixth stage. And at diameter (1.2m), the capacities are (1700m3), (1530m3) and (1475m3) at first, second and third stages respectively. But at diameter (1.4m), the capacities are (1590m3) at first and second stages. For all values of wave’s velocity, the capacities of surge tanks are (1760m3), (1530m3) and (1420m3) at first, second and third stages respectively. But the capacities of surge tanks at friction factor (0.007) are (1810m3), (1585m3) and (1245m3) at first, second and third stages respectively. However, for the capacity of surge tanks at the friction factor (0.008), it was mentioned when the surge tanks capacity of the diameter (1.2m) was mentioned. And when the friction factor is (0.009), the capacities are (1460m3) at first stage, (1415m3) at second and third stages and (570m3) at fourth stage

scholarly journals Condition Assessment of Solar Modules by Flash Test and Electroluminescence Test

Coatings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1361
Author(s):  
István Bodnár ◽  
Dávid Matusz-Kalász ◽  
Rafael Ruben Boros ◽  
Róbert Lipták
Keyword(s):  
Power Plant ◽  
Power Plants ◽  
Solar Power ◽  
Test Results ◽  
Performance Reduction ◽  
Solar Power Plants ◽  
Operational Errors ◽  
Hungarian State ◽  
Short Time ◽  
Real State

The Hungarian society and the Hungarian state are constantly increasing their solar capacity. More and more solar power plants are being put into operation. The largest of these has a 100 MW peak capacity. Such power plants do not require constant maintenance. However, in the case of low productivity, a conditional assessment is required. The reason for production loss can also be manufacturing, installation, and operational errors. A flying drone was used for finding failures by thermographic scouting. Furthermore, electroluminescent (EL) and flash tests give a comprehensive view of the real state of the modules in a mobile laboratory. We had the opportunity to summarize these test results of more than a thousand modules operating in a solar power plant. The report on the power plant shows that a significant part of the modules became unusable in a short time. After four years, 10% of the 260 Wp modules suffered a performance reduction of more than 10%.

scholarly journals Experimental Investigation on The Effect of Divergent Tower Solar Chimney on The Theoretical Power Potential

2021 ◽  
Vol 81 (1) ◽  
pp. 140-149
Author(s):  
Ahmad Jawad ◽  
Mohd Suffian Misaran ◽  
Md. Mizanur Rahman ◽  
Mohd Azlan Ismail
Keyword(s):  
Power Plant ◽  
Cost Ratio ◽  
Main Body ◽  
Test Results ◽  
Solar Chimney ◽  
Air Velocity ◽  
Higher Temperature ◽  
Electric Heat ◽  
Solar Chimney Power Plant ◽  
Tall Structure

Solar chimney power plant is a sustainable alternative for electricity generation using solar as the source of energy. In general, the main body of a solar chimney plant requires a tall structure which is costly and challenging to construct. Thus, it is important to increase the performance of the solar chimney power plant and have a better energy-cost ratio. This study aims to experimentally investigate the influence of divergent solar chimney as opposed to a cylindrical chimney on solar chimney performance. Three divergent scaled-down solar chimney model at 1-meter, 1.5-meter and 2-meter were fabricated and tested for its performance at various simulated heat loads. The test results were compared with similar heights cylindrical solar chimney. The experiments show that divergent solar chimney increases the theoretical power generation potential and improves the stalk effect and have higher outlet velocity compared to a cylindrical solar chimney. The power potential of the divergent chimney is increased up to 18 times with the maximum theoretical power obtain at 0.183W on the 2-meter divergent chimney. Higher temperature was recorded on the 2-meter divergent chimney outlet at 341.3k compared to 330.4k on the cylindrical chimney indicates better stack effect. The highest average velocities in the divergent and cylindrical chimneys were recorded under the electric heat load of 2 kW at 0.994 m/s and 0.820 m/s respectively in the 1-meter configuration. It is also observed that the air velocity in a shorter divergent chimney is higher than taller divergent chimney models while better compared to all cylindrical height. This study finds that a shorter divergent solar chimney produces greater energy compared to a higher cylindrical solar chimney. Therefore, it is possible to reduce the overall cost of solar chimney by reducing the height of the main structure without sacrificing the performance of the solar chimney.

Experimental characterization of composites to support an orthotropic plasticity material model

2017 ◽  
Vol 52 (14) ◽  
pp. 1847-1872 ◽  
Author(s):  
Bilal Khaled ◽  
Loukham Shyamsunder ◽  
Canio Hoffarth ◽  
Subramaniam D Rajan ◽  
Robert K Goldberg ◽  
...  
Keyword(s):  
Material Model ◽  
Unidirectional Composite ◽  
Deformation Model ◽  
Test Results ◽  
Dynamic Impact ◽  
Test Procedures ◽  
Stress Strain ◽  
Damage And Failure ◽  
Orthotropic Behavior

Test procedures for characterizing the orthotropic behavior of a unidirectional composite at room temperature and quasi-static loading conditions are developed and discussed. The resulting data consisting of 12 stress–strain curves and associated material parameters are used in a newly developed material model—an orthotropic elasto-plastic constitutive model that is driven by tabulated stress–strain curves and other material properties that allow for the elastic and inelastic deformation model to be combined with damage and failure models. A unidirectional composite—T800/F3900, commonly used in the aerospace industry, is used to illustrate how the experimental procedures are developed and used. The generated data are then used to model a dynamic impact test. Results show that the developed framework implemented into a special version of LS-DYNA yields reasonably accurate predictions of the structural behavior.

Control of Pipeline Dynamics With Disk Spring Restraints (Design Paper)

1991 ◽  
Vol 113 (2) ◽  
pp. 332-336 ◽  
Author(s):  
E. C. Goodling
Keyword(s):  
Power Plant ◽  
Water Hammer ◽  
Mixed Phase ◽  
Vapor Flow ◽  
Adequate Control ◽  
Process Piping ◽  
Disk Spring ◽  
Phase Water ◽  
Design Paper ◽  
Boiler Feedwater

Dynamic transients such as steam hammer or water hammer in power plant or process piping can generate high destructive reactions if rigid restraints or snubbers are used in an attempt to exert total control of pipe response. However, where some movement can be tolerated, adequate control can be maintained with much lower resulting loads in the restraining structures and components. The disk spring restraint has been demonstrated to be a practical device for controlling piping movements caused by typical dynamic upset conditions in steam and boiler feedwater piping and in drain lines carrying mixed phase (water and vapor) flow. This paper discusses the simplified mathematics used in estimating loads to design disk spring restraints for such applications.

scholarly journals Cutting Niches in Rock Salt by Means of a High-Pressure Water Jet in Order to Accelerate the Leaching of Storage Caverns for Hydrogen or Hydrocarbons

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1911 ◽  
Author(s):  
Waldemar Korzeniowski ◽  
Katarzyna Poborska-Młynarska ◽  
Krzysztof Skrzypkowski ◽  
Krzysztof Zagórski ◽  
Mariusz Chromik
Keyword(s):  
High Pressure ◽  
Rock Salt ◽  
Water Jet ◽  
Innovative Technology ◽  
Test Results ◽  
Significant Relationships ◽  
Rate Of Increase ◽  
Pressure Water ◽  
Preparatory Stage ◽  
High Pressure Water Jet

The article explores the potential for modification of the well-known salt cavern leaching process for brine production or/and hydrocarbon or hydrogen storage facilities, enabling the acceleration of the pace of acquiring new storage capacities with their increased geomechanical stability. The innovative technology is based on the use of high-pressure water jet technique for disc niche cutting in salt rock. The effect of such operations is a significant increase in the contact area of the water with the rock during cavern leaching and faster concentrated brine recovery already in the first leaching phase. This aspect was tested in 67 tests performed for three different types of rock salt: green, pink, and Spiza salt. Laboratory tests of the successive cutting of niches with a stream of water at 500 bar were carried out. The effectiveness of water jet was demonstrated and the possibilities of effective cutting of niches. Significant relationships were found between the obtained depth of niches at a given stream pressure and the duration of individual operations. Depending on the type of salt, the rate of increase in their depth was determined. The presented test results precede the much larger upscaling project, currently at the preparatory stage.

scholarly journals Study of Unsteady Flow in a Heat Exchanger by the Method of Characteristics

1992 ◽  
Vol 114 (4) ◽  
pp. 459-463 ◽  
Author(s):  
Yuan Mao Huang
Keyword(s):  
Heat Exchanger ◽  
Unsteady Flow ◽  
Transfer Rate ◽  
Method Of Characteristics ◽  
Governing Equations ◽  
One Dimensional ◽  
The Method Of Characteristics ◽  
Improvement Factor ◽  
The One ◽  
Good Agreement

The one-dimensional, unsteady flow in an air-to-air heat exchanger is studied. The governing equations are derived and the method of characteristics with the uniform interval scheme is used in the analysis. The effect of the fin improvement factor on the air temperature in the heat exchanger and the heat transfer rate of the heat exchanger, and air properties in the heat exchanger are analyzed. The numerical results are compared and show good agreement with the available data.

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