Analysis of the Cavitation in the Jet Flow Field of the V-Type Valve Orifice

2015 ◽  
Vol 779 ◽  
pp. 55-61
Author(s):  
Hao Ling Ren ◽  
Tian Liang Lin ◽  
Cheng Miao ◽  
Zhong Shen Li ◽  
Sheng Jie Fu
Keyword(s):  
Flow Field ◽  
Cross Section ◽  
Hydraulic Systems ◽  
Cavitation Model ◽  
Valve Orifice ◽  
The Common ◽  
Simulation Results ◽  
The Cross ◽  
Pressure Stress ◽  
Hydraulic Valves

Valve orifice is the common place that the cavitation easily occurs in the hydraulic systems. This paper introduces a criteria to estimate the inception of the cavitation of the V-type valve orifice with the stress state. Based on this criteria, a cavitation model which considers the dynamics of the cavity and incompressible gas is proposed to analyze the pressure, stress and the cavitation distribution of the phase in the V-type orifice. The distributions of the cavitation along the axis and the cross section are analyzed. The simulation results show that the cavitation is easily occurred in the downstream just after the orifice and the bubbles are mostly gathered in the top of the cross section which is vertical to the axis of the flow field. The simulation results is reasonable according to the facts. Accordingly, the cavitation of the V-type orifice is predicted reasonably. The research and results of this paper are useful for the design of the hydraulic valves.

Numerical Simulation of Atmospheric Flow Field around Bridge

2013 ◽  
Vol 368-370 ◽  
pp. 1379-1382
Author(s):  
Ying Jia ◽  
Li Zhang ◽  
Sheng Zhang
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Pressure Distribution ◽  
Cross Section ◽  
Horizontal Plane ◽  
Atmospheric Flow ◽  
Airflow Field ◽  
Distribution Laws ◽  
The Cross

This paper carries out a numerical simulation of the atmospheric flow field around bridge. The variation law of airflow field around bridge is studied. Velocity and pressure distribution laws of flow field in horizontal plane and the cross-section are discussed, and influence range of flow field around bridge area is identified.

Common Ownership in America: 1980–2017

2021 ◽  
Vol 13 (3) ◽  
pp. 273-308
Author(s):  
Matthew Backus ◽  
Christopher Conlon ◽  
Michael Sinkinson
Keyword(s):  
Time Series ◽  
Cross Section ◽  
Cash Flow ◽  
Historical Perspective ◽  
Common Ownership ◽  
Dramatic Rise ◽  
The Common ◽  
The Cross ◽  
Cash Flow Rights ◽  
And Control

We empirically assess the implications of the common ownership hypothesis from a historical perspective using the set of S&P 500 firms from 1980 to 2017. We show that the dramatic rise in common ownership in the time series is driven primarily by the rise of indexing and diversification and, in the cross section, by investor concentration, which the theory presumes to drive a wedge between cash flow rights and control. We also show that the theory predicts incentives for expropriation of undiversified shareholders via tunneling, even in the Berle and Means (1932) world of the widely held firm. (JEL D22, G32, G34, L21, L25)

Ground-state and isomeric-state cross-sections for 92Mo(n,α)89Zr and 95Mo(n,p)95Nb reactions in the 13–15 MeV energy region

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Junhua Luo ◽  
Li Jiang
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Ground State ◽  
Nuclear Decay ◽  
Excitation Functions ◽  
Total Cross Sections ◽  
Γ Ray ◽  
Simulation Results ◽  
The Cross ◽  
Isomeric Ratios

Abstract The (n,α) and (n,p) cross-sections and their isomeric ratios (σ m /σ g ) were measured at 13–15 MeV for 92Mo and 95Mo by activation and off-line γ-ray spectrometry. The activated Mo samples combined with Al foils were used to obtain the cross-section values and the neutron flux, generated using the 3H(d,n)4He reaction. The cross-sections of the ground states were obtained using the metastable state absolute cross-sections and the residual nuclear decay rule. The excitation functions, total cross-sections, and isomeric ratios for the 92Mo(n,α)89m,gZr and 95Mo(n,p)95m,gNb reactions were calculated using the TALYS-1.95 software. 92Mo(n,α)89m + gZr and 95Mo(n,p)95m + gNb reaction excitation functions were obtained using the EMPIRE-3.2.3 package. These simulation results were compared with the corresponding experimental data and with the evaluated data from the ENDF/B-VIII.0, JEFF-3.3, CENDL-3, and ROSFOND libraries. Only partial agreements were observed.

scholarly journals Simulasi Numerik Reaksi Fusi Nuklir dengan menggunakan Metode Wong

2016 ◽  
Vol 6 (01) ◽  
pp. 50
Author(s):  
Muhammad Zamrun Firihu ◽  
Viska Inda Variani ◽  
J Justina
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Cross Section ◽  
Fusion Reaction ◽  
Fusion Cross Section ◽  
Chi Square ◽  
Simulation Results ◽  
The Cross

The numerical simulation for calculating the cross section of fusion reaction is done by using Wong formula. We especially calculated the cross section for the fusion reaction of light systems, i.e. 12C+12C, 16O+12C and 16O+16O reactions. We compared the obtained cross section with experimental data. In order to check the accuracy of the calculations, the chi-square analisys is then permormed. We found that the simulation results of the fusion cross section obtained using Wong Formula well explain the experimetal data of the fusion cross section for the 12C+12C, 16O+12C and 16O+16O reactions. This finding indicates that the Wong formula can be used for studing the fusion reaction of light systems.

Heat Transfer Enhancement of Laminar Internal Flows Using Electrically-Induced Swirling Effect

2012 ◽  
Author(s):  
Reza Baghaei Lakeh ◽  
Majid Molki
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Flow Field ◽  
Electric Field ◽  
Convective Heat Transfer ◽  
Cross Section ◽  
Convective Heat ◽  
Parallel Plates ◽  
Internal Flows ◽  
The Cross

A computational and experimental approach is conducted to enhance the convective heat transfer in fully developed laminar flow in parallel-plates configuration. Laminar internal flows are associated with unchanging Nusselt number along the channel due to the fully developed condition of the boundary layer. Inducing a swirling effect along the flow can disturb the flow field and enhance the convective heat transfer from the plates to the flow. The interaction between an electrically-induced secondary flow and the pressure-driven main flow complicates the flow field and causes a swirling effect. In this study, the electric field governing equations are solved numerically using finite volume method. In order to obtain a proper boundary condition for the charge density, an experimental setup was utilized to measure the time-averaged corona current. The distribution of electric field and charge density on the cross section of the channel is obtained and adopted to find the electric body-force at each point. The flow field computations are performed with FLUENT CFD code on a three-dimensional model using second-order upwind scheme. The secondary flow field is imposed on the cross section of the channel by corona discharge. An array of emitting and receiving flat electrodes are embedded in the parallel plates to induce a corona jet on the cross section of the channel. The axial component of velocity along with an array of corona jets gives birth to a swirling flow which can significantly enhance the convection coefficient and Nusselt number in the fully developed regime. This investigation indicated that the convective heat transfer can be enhanced up to 173% with an applied potential of 24 kV.

scholarly journals Suppression of Brazier Effect in Multilayered Cylinders

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Hiroyuki Shima ◽  
Motohiro Sato ◽  
Sung-Jin Park
Keyword(s):  
Cross Section ◽  
Circular Cross Section ◽  
Interlayer Coupling ◽  
Theoretical Formulation ◽  
Cross Sectional ◽  
Quantitative Manner ◽  
Hollow Cylinders ◽  
The Common ◽  
The Cross ◽  
Brazier Effect

When a straight hollow tube having circular cross-section is bent uniformly into an arc, the cross-section tends to ovalize or flatten due to the in-plane stresses induced by bending; this ovalization phenomenon is called the Brazier effect. The present paper is aimed at theoretical formulation of the Brazier effect observed in multilayered cylinders, in which a set of thin hollow cylinders are stacked concentrically about the common axis. The results indicate that mechanical couplings between stacked cylinders are found to yield pronounced suppression of the cross-sectional ovalization. Numerical computations have been performed to measure the degree of suppression in a quantitative manner and to explore how it is affected by the variations in the bending curvature, the number of stacked cylinders, and the interlayer coupling strength.

scholarly journals An Investigation into Accumulative Difference Mechanism in Time and Space for Material Removal in Micro-EDM Milling

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 711
Author(s):  
Qi Jing ◽  
Yongbin Zhang ◽  
Lingbao Kong ◽  
Min Xu ◽  
Fang Ji
Keyword(s):  
Cross Section ◽  
Process Parameters ◽  
Material Removal ◽  
Machining Accuracy ◽  
Tool Electrode ◽  
Micro Edm ◽  
Cylindrical Electrode ◽  
Time And Space ◽  
Simulation Results ◽  
The Cross

In micro-electrical discharge machining (micro-EDM) milling, the cross-section of the microgroove machine is frequently not an ideal rectangle. For instance, there are arc shapes on the bottom and corners, and the sidewall is not steep. The theoretical explanation for this phenomenon is still lacking. In addition to the tip discharge effect, the essential reason is that there is an accumulative difference in time and space during the shape change process of a tool electrode and the microstructure formation on a workpiece. The process parameters are critical influencing factors that determine this accumulative difference. Therefore, the accumulative difference mechanism in time and space is investigated in this paper, and then a theoretical model is developed to simulate the micro-EDM milling process with a straight-line single path. The simulation results for a cylindrical electrode at the two rotational speeds of 0 (nonrotating) and 300 rpm are compared, while the results for a cylindrical electrode and a square electrode at a rotation speed of 0 are also compared to verify that different process parameters generate accumulative differences in the time and space of material removal. Finally, micro-EDM milling experiments are carried out to verify the simulation model. The maximum mean relative deviation between the microgroove profiles of simulation results and those of experiments is 11.09%, and the profile shapes of simulations and experiments have a good consistency. A comparative experiment between a cylindrical electrode and a hollow electrode is also performed, which further verifies the mechanism revealed in the study. Furthermore, the cross-section profile of a microgroove can be effectively controlled by adjusting the process parameters when utilising these accumulative differences through fabricating a microgroove with a V-shaped cross-section by a square electrode and a microgroove with a semi-circular cross-section by a cylindrical electrode. This research provides theoretical guidance for solving the problems of the machining accuracy of detail features in micro-EDM milling, for instance, to machine a microgroove with an ideal rectangular cross-section.

scholarly journals Note on Electrolytic Conduction

1891 ◽  
Vol 17 ◽  
pp. 302-303 ◽  
Author(s):  
Robert L. Mond
Keyword(s):  
Cross Section ◽  
Electrolytic Cell ◽  
Small Hole ◽  
Common Electrode ◽  
The Common ◽  
The Cross

At the suggestion of Professor P. G. Tait, I undertook the further investigation of an experiment, an account of which he communicated to this Society on Monday, the 15th of April 1878.In this experiment a platinum plate of moderate thickness is inserted between the electrodes of an electrolytic cell, so as to completely fill the cross-section. This platinum plate thus becomes the common electrode of two cells, and on perforating it it is found that a comparatively small hole at once changes its functions to that of an obstacle in one cell.

A New Approach to the Demonstration of Oxidase-Localization Using Tannic Acid Or Catechin

1973 ◽  
Vol 31 ◽  
pp. 698-699
Author(s):  
V. Mizuhira ◽  
Y. Futaesaku
Keyword(s):  
Cross Section ◽  
Tannic Acid ◽  
Elastic Fiber ◽  
The Other ◽  
New Approach ◽  
Tissue Block ◽  
Active Reaction ◽  
The Cross

Previously we reported that tannic acid is a very effective fixative for proteins including polypeptides. Especially, in the cross section of microtubules, thirteen submits in A-tubule and eleven in B-tubule could be observed very clearly. An elastic fiber could be demonstrated very clearly, as an electron opaque, homogeneous fiber. However, tannic acid did not penetrate into the deep portion of the tissue-block. So we tried Catechin. This shows almost the same chemical natures as that of proteins, as tannic acid. Moreover, we thought that catechin should have two active-reaction sites, one is phenol,and the other is catechole. Catechole site should react with osmium, to make Os- black. Phenol-site should react with peroxidase existing perhydroxide.

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