Analysis of Droplet Impacting on Inclined Wall

2020 ◽  
Author(s):  
Bowen Chen ◽  
Bo Wang ◽  
Bingzheng Ke ◽  
Ru Li ◽  
Ruifeng Tian
Keyword(s):  
Steam Generator ◽  
High Speed ◽  
Nuclear Power ◽  
Separation Efficiency ◽  
Inertial Force ◽  
High Speed Photography ◽  
Separation Mechanism ◽  
The Relationship ◽  
Plate Separator

Abstract The steam generator is an important part of the nuclear power plant, and the corrugated plate separator plays the important role of drying steam in the steam generator to improve power generation efficiency and protect the safety of the system. The separation mechanism of the corrugated plate separator is relatively complicated. The droplets are moved by the drag force of the steam and gravity in the corrugated plate separator, and captured by the wall of the corrugated plate separator. When the velocity is increased, the inertial force of droplet is increased, so that the droplet is more easily captured by the wall of the corrugated plate separator, and the separation efficiency of the corrugated plate separator is increased. In this paper, the phenomenon of droplet impact on the inclined wall is studied by high-speed photography technology, and the cause and mechanism of the phenomenon are analyzed. By analyzing the spreading and splashing on the droplets impacting on the inclined wall, the relationship between the inclination angle of the droplet impacting on the inclined wall and the spreading is obtained, and the influence of droplets with different Weber numbers, and dry and wetted walls were analyzed, which provide a basis for the optimization of the corrugated plate separator.

Experimental Study on Splashing During Liquid Jet Impingement Onto a Liquid Film

2016 ◽  
Author(s):  
Zhan Yi ◽  
Naoki Oya ◽  
Koji Enoki ◽  
Tomio Okawa ◽  
Shuji Ohno ◽  
...  
Keyword(s):  
Liquid Film ◽  
High Speed ◽  
Nuclear Power ◽  
Jet Impingement ◽  
Liquid Jet ◽  
Jet Engine ◽  
Transition Length ◽  
The Impact ◽  
The Relationship ◽  
Fire Accident

A liquid jet is of considerable importance in many industrial fields including jet cleaning, jet engine and combustion. As an important example, the Monju nuclear power plant in Japan experienced a sodium leak in 1995. This led to a fire accident because the sodium reacted with oxygen in the air. To predict the significance of the fire accident, accurate evaluation of the amount of splashed droplets caused by the sodium jet impingement is of great importance. In this work, the relationship between the condition of a liquid jet and the amount of splashed droplets is explored experimentally. In the experiments, a liquid jet was emanated vertically downward from a circular nozzle onto a liquid film formed on a horizontal plate. Visualization using a high speed camera was performed to observe the condition of the liquid jet. From the nozzle, the mode of the liquid jet changed jet, lump and drop. Here, the jet mode means the continuous jet with smooth surface, the lump mode the continuous jet with disturbed surface and the drop mode the broken jet. Dependences of the transition length to each mode on the important parameters such as the jet velocity and the nozzle diameter were investigated. Measurement was also conducted for the splash ratio that is defined as the ratio of the amount of splashed droplets to the jet flow rate. It was found that the splash ratio is high when the liquid jet is in the drop mode at the impact point. It was shown that the splash ratio can be correlated well as a function of the impact Weber number and the Strouhal number of the droplets impinging the liquid film.

The Role Of High Speed Photography In Plasma Instability Research On The Aec Tokamak

1987 ◽  
Author(s):  
J. D. Fletcher ◽  
D. P. Coster ◽  
J. A. M. De Villiers ◽  
P. B. Kotze ◽  
G. Nothnagel ◽  
...  
Keyword(s):  
High Speed ◽  
Plasma Instability ◽  
High Speed Photography

An Experimental Model Study of Steam Generator Tube Loading During a Sudden Depressurization

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Ouajih Hamouda ◽  
David S. Weaver ◽  
Jovica Riznic
Keyword(s):  
Experimental Model ◽  
Steam Generator ◽  
High Speed ◽  
Nuclear Power ◽  
Tube Bundle ◽  
Cross Flow ◽  
Working Fluid ◽  
Two Phase ◽  
Steam Generator Tube ◽  
Model Study

This paper presents the results of an experimental model study of the transient loading of steam generator tubes during a postulated main steam line break (MSLB) accident in a nuclear power plant. The problem involves complex transient two-phase flow dynamics and fluid-structural loading processes. A better understanding of this phenomenon will permit the development of improved design tools to ensure steam generator tube integrity. The pressure and temperature were measured upstream and downstream of a sectional model of a tube bundle in cross-flow, and the transient tube loads were directly measured using dynamic piezoelectric load cells. High-speed videos were taken to observe and better understand the flow phenomena causing the tube loading. The working fluid was R-134a and the tube bundle was a normal triangular array with a pitch ratio of 1.36. The flow through the bundle was choked for the majority of the transient. The transient tube loading is explained in terms of the associated fluid mechanics. An empirical model is developed that enables the prediction of the maximum tube loads once the pressure drop is known.

Effects of Heating Surface Materials on a Liquid–Solid Contact State in a Sessile Drop-Boiling System

1993 ◽  
Vol 115 (1) ◽  
pp. 222-230 ◽  
Author(s):  
S. Inada ◽  
W.-J. Yang
Keyword(s):  
High Speed ◽  
Sessile Drop ◽  
Bubble Radius ◽  
Heating Surface ◽  
Experimental Investigations ◽  
High Speed Photography ◽  
Solid Contact ◽  
Contact State ◽  
Interfacial Pressure ◽  
The Relationship

Three experimental investigations are performed on the liquid–solid contact state at the instant when a liquid comes in contact with a heating surface in the transition-boiling regime between the maximum evaporation rate point and the spheroidal state: (1) measuring the piezoelectric potential by means of a quartz oscillator being placed on the heating surface, (2) monitoring the boiling sound generated at the instant of liquid–solid contact using a condenser microphone, and (3) observation of drop behavior, by means of high-speed photography. The information obtained from these three investigations is synthesized to quantify the liquid–solid contact state. The study has disclosed the roles of thermal properties and heating surface temperatures on the endurance time of the instantaneous liquid–solid contact state and the relationship between the critical bubble radius and the measured vapor–liquid interfacial pressure difference.

Evaluation of single heated channel and subchannel modeling of a nuclear once through steam generator (OTSG)

Kerntechnik ◽  
2020 ◽  
Vol 85 (1) ◽  
pp. 54-67
Author(s):  
A. Hamedani ◽  
O. Noori-Kalkhoran ◽  
R. Ahangari ◽  
M. Gei
Keyword(s):  
Steam Generator ◽  
Nuclear Power ◽  
Axial Direction ◽  
Pressurized Water Reactors ◽  
Steam Generators ◽  
Pressurized Water ◽  
Heated Channel ◽  
Water Reactors ◽  
Secondary Side

Abstract Steam generators are one of the most important components of pressurized-water reactors. This component plays the role of heat transfer and pressure boundary between primary and secondary side fluids. The Once Through Steam Generator (OTSG) is an essential component of the integrated nuclear power system. In this paper, steady-state analysis of primary and secondary fluids in the Integral Economizer Once Through Steam Generator (IEOTSG) have been presented by Single Heated Channel (SHC) and subchannel modelling. Models have been programmed by MATLAB and FORTRAN. First, SHC model has been used for this purpose (changes are considered only in the axial direction in this model). Second, the subchannel approach that considers changes in the axial and also radial directions has been applied. Results have been compared with Babcock and Wilcox (B&W) 19- tube once through steam generator experimental data. Thermal- hydraulic profiles have been presented for steam generator using both of models. Accuracy and simplicity of SHC model and importance of localization of thermal-hydraulic profiles in subchannel approach have been proved.

Numerical Simulation Analysis of Corrugated Plate With Hook

2017 ◽  
Author(s):  
Bowen Chen ◽  
Ruifeng Tian ◽  
Feng Mao ◽  
Wei He
Keyword(s):  
Pressure Drop ◽  
Steam Turbine ◽  
Steam Generator ◽  
Nuclear Power ◽  
High Efficiency ◽  
Separation Efficiency ◽  
Simulation Analysis ◽  
Saturated Steam ◽  
System Pressure ◽  
Water Separator

Separation device is one of the important equipment in the steam generator, which reduce the humidity, and it is a key device of nuclear plant which can guarantee the saturated steam to the steam turbine to provide clean. In nuclear power plant, the nuclear steam turbine uses saturated steam directly, so the separation system in steam generator requires a high efficiency of separation. Because of its simple process, high separation efficiency, low system pressure drop and large capacity, small volume, long life and other advantages, corrugated plate in water separator technology is more and more extensive application in the production process. In this paper, the corrugated plate water separator is simulated research, through the establishment of a two-dimensional model of corrugated plate, separation efficiency and pressure drop of corrugated plate is simulated. By setting the different air speed, different gap of hook-plate, observe the change of the pressure drop and separation efficiency, and analyzes the internal mechanism of the foundation for the optimization of corrugated plate dryer.

Solid particle erosion of metals: the removal of surface material by spherical projectiles

1976 ◽  
Vol 348 (1654) ◽  
pp. 379-392 ◽  
Keyword(s):  
High Speed ◽  
Impact Angle ◽  
Solid Particle Erosion ◽  
High Speed Photography ◽  
Surface Material ◽  
Crater Formation ◽  
Particle Erosion ◽  
Sand Particles ◽  
The Impact

Experiments are described in which steel spheres were projected obliquely onto mild steel targets. It is shown that this successfully simulates a class of impact occurring during the erosion of metals by dust and sand particles. The dependence of the crater dimensions on impact angle and velocity is determined and, using high speed photography, the energy balance in the impact process is studied. A model of crater formation is proposed which accurately predicts the volume of material displaced and the energy lost by an impacting sphere. It is found that metal becomes detached along a band of intense subsurface shear; calculation shows that this is associated with the production of local high temperatures. The data and analysis presented provide a basis for assessing the rôle of the ploughing component of deformation in erosion.

scholarly journals Study on Measure Approach of Void Fraction in Narrow Channel Based on Fully Convolutional Neural Network

2021 ◽  
Vol 9 ◽  
Author(s):  
Wenjun Chu ◽  
Yang Liu ◽  
Liqiang Pan ◽  
Hongye Zhu ◽  
Xingtuan Yang
Keyword(s):  
Neural Network ◽  
Convolutional Neural Network ◽  
Void Fraction ◽  
High Speed ◽  
Nuclear Power ◽  
Flow Boiling ◽  
Image Features ◽  
High Speed Photography ◽  
Flow State ◽  
Narrow Channels

Void fraction is one of the key parameters for gas-liquid study and detection of nuclear power system state. Based on fully convolutional neural network (FCN) and high-speed photography, an indirect void fraction measure approach for flow boiling condition in narrow channels is developed in this paper. Deep learning technique is applied to extract image features and can better realize the identification of gas and liquid phase in channels of complicated flow pattern and high void fraction, and can obtain the instantaneous value of void fraction for analyzing and monitoring. This paper verified the FCN method with visual boiling experiment data. Compared with the time-averaged experimental results calculated by the energy conservation method and the empirical formula, the relative deviations are within 11%, which verifies the reliability of this method. Moreover, the recognition results show that the FCN method has promising improvement in the scope of application compared with the traditional morphological method, and meanwhile saves the design cost. In the future, it can be applied to void fraction measurement and flow state monitoring of narrow channels under complex working conditions.

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