scholarly journals Correction and laboratory investigation for energy loss coefficient of square-edged orifice plate

2021 ◽  
Vol 104 (2) ◽  
pp. 003685042110185
Author(s):  
Ai Wanzheng ◽  
Zhu Pengfei
Keyword(s):  
Energy Loss ◽  
Model Experiment ◽  
Plate Thickness ◽  
Primary Objective ◽  
Loss Coefficient ◽  
Orifice Plate ◽  
Discharge Tunnel ◽  
Energy Dissipater ◽  
Contraction Ratio ◽  
Relative Errors

A lot of studies have shown that the hydraulic characteristics of orifice plate are mainly controlled by its contraction ratio, but the thickness of square-edged orifice plate also has many impacts on energy loss characteristics. The primary objective of this study was to investigated the effects of square-edged orifice plate thickness on energy loss characteristics. In this paper, the effects of square-edged orifice plate thickness on energy loss characteristics are investigated by numerical simulation using CFD. Orifice plate discharge tunnel is axial symmetric, two dimensional numerical simulations of orifice plate discharge tunnel flow was used. The equation (9) for calculating energy loss coefficient of square-edged orifice plate energy dissipater considering the influence of thickness is proposed. The results of the present research demonstrate that energy loss coefficient decreases with increase of the orifice plate thickness. The results of model experiment are consistence with the results calculated by using rectified equation in present paper. The CFD simulations and Model experiment for the flow through an orifice plate are carried out. For square-edged orifice plate energy dissipater, the relative orifice plate thickness T/D has remarkable impacts on its energy loss coefficient ξ. The Traditional equation (8) is corrected by numerical results. The equation (9) for calculating energy loss coefficient of square-edged orifice plate energy dissipater considering the influence of thickness is proposed and this equation is available in the condition of d/D = 0.4–0.8, T/D = 0.05–0.25, and Re > 105(Re is Reynolds number). Comparing with the physical model experimental data, the relative errors of equation (9) is smaller than 15%.

The Incipient Cavitation Number of Square-Edged Orifice Plate

2014 ◽  
Vol 568-570 ◽  
pp. 1702-1705
Author(s):  
Wei Jun Wang
Keyword(s):  
Reynolds Number ◽  
Plate Thickness ◽  
Cavitation Number ◽  
Orifice Plate ◽  
Simulation Methods ◽  
Contraction Ratio ◽  
Theoretical Considerations

In the present paper, the incipient cavitations number was analyzed by theoretical considerations. By using simulation methods, it could be regarded that the incipient cavitations number was mainly dominated by the contraction ratio of the orifice plate. The less the contraction ratio of the orifice plate is, the larger is the incipient cavitations number. The effects of orifice plate’ thickness on the incipient cavitations number was not obviously and could be neglected. When Reynolds number is more than 105, Reynolds number has little impact on the incipient cavitations number.

Review on the Research of Orifice Plate Hydraulic Characteristics

2014 ◽  
Vol 590 ◽  
pp. 101-104
Author(s):  
Jia Hong Wang ◽  
Wan Zheng Ai
Keyword(s):  
Energy Loss ◽  
Orifice Plate ◽  
Effective Energy ◽  
Hydraulic Characteristics ◽  
Energy Dissipater

Orifice plate energy dissipater, as a kind of effective energy dissipater with characteristics of economic, has become welcomed more and more by hydraulics researchers. Although many researches have been conducted on orifice plate’s hydraulic characteristics, there are many other issues, which are closely related with orifice plate’s energy loss and cavitations, needed to be solved. Some issues on orifice plate’s hydraulic characteristics have been put forward in this paper so as to strengthen research in this field.

Numerical Simulation of Characteristics of Sudden Reduction Tube Flow Based on FLUENT

2011 ◽  
Vol 255-260 ◽  
pp. 3461-3465
Author(s):  
Wan Zheng Ai ◽  
Bai Gang Huang
Keyword(s):  
Reynolds Number ◽  
Energy Loss ◽  
Loss Coefficient ◽  
Experiment Data ◽  
Empirical Expression ◽  
Contraction Ratio ◽  
Flow Through ◽  
Spillway Tunnel ◽  
Theoretical Considerations ◽  
Sudden Reduction

Sudden reduction tube was always used in spillway tunnel, drainage pipes and so on. The energy loss coefficient of sudden reduction tube flows is an important index of sudden reduction tube. In the present paper, this coefficient and relative parameters, such as the contraction ratio and Reynolds number of the flow through sudden reduction tube, were analyzed by theoretical considerations, and their relationships were obtained by the numerical simulations. It could be concluded that the energy loss coefficient was mainly dominated by the contraction ratio. The less the contraction ratio is, the larger is the energy loss coefficient. When Reynolds number is more than 105, Reynolds number has little impact on it. An empirical expression, which was verified by comparison with other experiment data, was presented to calculate the energy loss coefficient of sudden reduction tube flows.

scholarly journals Research on the Flow Characteristics of Sudden-Reduction Oil Tube

2015 ◽  
Vol 9 (1) ◽  
pp. 77-79 ◽  
Author(s):  
Zhibin Zhang ◽  
Chunxi Lin ◽  
Weiqiang Ye ◽  
An Wei ◽  
Leming Xiao ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Energy Loss ◽  
Flow Characteristics ◽  
Orifice Plate ◽  
Empirical Expression ◽  
Contraction Ratio ◽  
Region Length ◽  
Sudden Reduction

The backflow region length in sudden-reduction oil tube is not only closely associated with its energy loss, but is also closely related to the partition between orifice plate and plug. In this paper, the characteristics of backflow region length in sudden-reduction oil tube are researched. The results illustrated that backflow region length decreases with the increase in the contraction ratio. Moreover, when Reynolds number is more than 105, Reynolds number has little impact on backflow region length. Empirical expression about backflow region length in sudden-reduction oil tube is also discussed in this paper.

scholarly journals REGRESSION ANALYSIS OF THE COEFFICIENTS OF THE LOSS OF VIBRATIONAL ENERGY WHEN CALCULATING THE NOISE FROM OSSETIAN AND BORING MACHINES

Akustika ◽  
2019 ◽  
Vol 34 ◽  
pp. 95-99
Author(s):  
Alexander Shashurin ◽  
Marat Goguadze ◽  
Alexander Chukarin
Keyword(s):  
Regression Analysis ◽  
Energy Loss ◽  
Least Squares ◽  
Natural Frequencies ◽  
Vibrational Energy ◽  
Regression Coefficient ◽  
Geometric Mean ◽  
Loss Coefficient ◽  
Method Of Least Squares ◽  
Boring Machines

The purpose of this analysis is to approximate the analytical dependences which allow to calculate the vibrational energy loss coefficient at any frequency when calculating the noise from the axle lathe and boring machines. A regression analysis was conducted using the method of least squares. The paper presents the results of the regression coefficient calculations. The dependences obtained allow us to determine the loss coefficient value not only at the geometric mean frequencies of the octave spectrum, but also at the natural frequencies of oscillations.

Effects of Trenched Holes on Film Cooling of a Contoured Endwall Nozzle Vane

2010 ◽  
Author(s):  
Giovanna Barigozzi ◽  
Giuseppe Franchini ◽  
Antonio Perdichizzi ◽  
Silvia Ravelli
Keyword(s):  
Energy Loss ◽  
Film Cooling ◽  
Loss Coefficient ◽  
Flow Rate Ratio ◽  
Pressure Probe ◽  
Intensity Level ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Coolant Injection ◽  
Cylindrical Holes

The present paper investigates the effects of the application of trenched holes in the front part of a contoured film cooled endwall. Two trench configurations were tested, changing the trench depth. Tests have been carried out at low speed (M2is = 0.2) and low inlet turbulence intensity level, with coolant mass flow rate ratio varied within the 0.5–2.5% range. Pressure probe traverses were performed downstream of the vane trailing edge to show the secondary flow field modifications and to evaluate trench additional losses. Endwall distributions of film cooling effectiveness have been obtained by TLC technique. For each injection condition energy loss coefficient and film cooling effectiveness distributions were analyzed and compared to the ones obtained from rows of cylindrical holes. Laterally and area averaged effectiveness as well as pitch and mass averaged kinetic energy loss coefficient were computed to enlighten any change induced by the introduction of trenched holes. A uniform and high thermal coverage was obtained in the region just downstream of the trench, but it quickly decayed, because of enforced mixing of coolant with main-flow. Compared to the cylindrical hole configuration, trenches are able to provide a higher global cooling effectiveness, but a larger amount of coolant injection is required. The introduction of both trenches is responsible for a secondary thermodynamic loss increase of about 0.7%, at low coolant injection rates. Increasing blowing rates, the additional loss is going to vanish.

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