scholarly journals Options to Evaluate The Effects of a Change in the Shape of the Flow Cross-Section of a Ball Valve on Its Flow Control Properties

2014 ◽  
Vol 18 (1) ◽  
pp. 38-43
Author(s):  
Peter Lukáč ◽  
Peter Horbaj ◽  
Jarmila Sedláková
Keyword(s):  
Flow Control ◽  
Cross Section ◽  
Ball Valve ◽  
Flow Cross Section ◽  
Flow Cross

Reconstruction of the Flow Cross-Section Temperature Based on the Radiation Balance Between Infinitesimal

2011 ◽  
Vol 216 ◽  
pp. 238-243 ◽  
Author(s):  
R. Liu ◽  
X. Wan ◽  
Z.M. Zhang ◽  
W.H. Xiao
Keyword(s):  
Temperature Measurement ◽  
Cross Section ◽  
Three Dimensional ◽  
Emission Spectra ◽  
Test System ◽  
Difficult Problem ◽  
Radiation Balance ◽  
Flow Cross Section ◽  
Reconstructed Temperature ◽  
Flow Cross

The reconstruction of three-dimensional temperature field is a difficult problem. But three-dimensional temperature measurement can be simplified by the reconstruction of the flow cross-section temperature. In this paper, a theory of reconstruction is proposed and a simulation test system is implemented by MATLAB based on emission spectra tomography (EST) and radiation temperature measurement, which also take the emission and absorption characteristics in the processing of radiative transfer under consideration. Finally, by analyzing the difference of the original temperature and reconstructed temperature we can get the accuracy of the reconstruction theory.

Effects of Mesh-Induced Upstream Turbulence on Flip-Flop Flow Inside Diamond-Shaped Cylinder Bundles

Volume 3 ◽  
2004 ◽  
Author(s):  
Shinzaburo Umeda ◽  
Wen-Jei Yang
Keyword(s):  
Reynolds Number ◽  
Cross Section ◽  
Power Spectra ◽  
Dominant Frequency ◽  
Two Dimensional ◽  
Cross Sectional ◽  
Flow Measurements ◽  
Flip Flop ◽  
Flow Cross Section ◽  
Flow Cross

An experimental study is conducted to investigate effects of mesh-induced upstream turbulence on flip-flop flow inside diamond-shaped cylinder bundles. In order to quantitatively treat flip-flop flow induced by the self-excited oscillation of vortices, flow measurements by means of two-dimensional particle image velocimetry (PIV) and two-dimensional laser Doppler velocimetry (LDV) are employed. Flow cross-sectional area and flow rate are varied to change the Reynolds number in the bundles. A turbulence mesh is installed a very short distance upstream from the inlet of the test section. The LDV is employed to measure velocity changes in the flip-flop flow, while power spectra representing its oscillating characteristics are determined from LDV data. The dominant frequency is observed special features are disclosed in the relationship between the Reynolds number and the Strouhal number representing the dimensionless dominant frequency in all power spectra of the flip-flop flow. It is disclosed that both the flow cross section and the upstream turbulence are related to the generation of flip-flop flow in complex manner, and that the effects of the turbulence differ depending upon the flow cross section.

Vertical Velocity Profile on the Noncircular Flow Cross-Section of Water Intake Pipeline with Deposition on Bottom

2013 ◽  
Vol 864-867 ◽  
pp. 2050-2055
Author(s):  
Xiao Xiao Li ◽  
Xiao Dong Zhao ◽  
Xiao Feng Luo
Keyword(s):  
Cross Section ◽  
Water Intake ◽  
Cross Sections ◽  
Vertical Velocity ◽  
Maximum Velocity ◽  
Mean Velocity ◽  
Flow Cross Section ◽  
Fine Sediments ◽  
Deposition Thickness ◽  
Flow Cross

Under small water-intake flow or overhaul periods, sediments deposit in the water intake pipeline with noncircular flow cross-section formed. According to the hydrostatic settling test results of fine sediments in circular pipeline, the sectional features of the deposition on pipe bottom is provided. And the vertical velocity profiles on perpendicular bisectors of noncircular flow cross-sections are measured under three kinds of typical deposition thickness. The relative positions of the maximum velocity point and the center of flow cross-section should be determined with an overall consideration to the two factors of wall roughness and wall restraint which is controlled by the transverse width of flow cross-section. When the mean velocity of flow cross-section keeps a constant value, the larger the deposition thickness is, the larger the velocity near the deposition surface, which is more favorable for sediment incipient motion.

Experimental and numerical investigations of choked air flow and heat transfer in a ball valve for optimization the cross-sectional area

2019 ◽  
Vol 30 (5) ◽  
pp. 2705-2737 ◽  
Author(s):  
Davood Toghraie ◽  
Hojjatollah Heidari Khouzani
Keyword(s):  
Fluid Flow ◽  
Supersonic Flow ◽  
Flow Control ◽  
Cross Section ◽  
Flow Rate ◽  
Ball Valve ◽  
Flow Coefficient ◽  
Fluid Flow Rate ◽  
Content Type ◽  
Percentage Difference

Purpose The purpose of this study is to understand the functional properties of ball valve in a compressible flow and simulation of experimental data collection of ball valve, was completely simulated. Design/methodology/approach Equations are solved according to finite volume and simplified algorithms. By measuring the flow parameters, including pressure and temperature at different points in the simulation circuit, flow coefficients and localized drop in the valve were determined in different openness cases of test valve and compared with experimental results. Determining a graph for flow coefficient variations in terms of the percentage of openness of the valve is very effective on the flow control as well as on optimizing its cross-section. Findings In the supersonic flow, flow coefficients and local drops of the valve are dependent on several parameters, including fluid flow rate. Flow coefficient graphs at different angles of the test valve show that by increasing the valve opening angle, the flow coefficient increases so that it reaches from 1.72 m3/h at a 30° angle to 46.29 m3/h at a 80° angle. It should be noted that these values in the experimental test were obtained 1.53 m3/h and 49.68 m3/h, respectively, and the percentage difference of these values by simulation was obtained for the angle of 30 degrees 11.7% and for the angle of 80°, about 7% per hour at an angle of 80°. Also, the coefficients of localized loss at different angles of test valve show that by increasing the angle of opening of the valve, the amount of localized loss decreases, so that the average value of 1515.2 in the angle of 30° reaches 1.9 at an angle of 80°. The percentage difference of these values by simulation, for the angle of 30° and 3.5% for the angle of 80°, was about 11.1%. Originality/value Determining a graph for flow coefficient variations versus the percentage of openness of the valve is very effective on the flow control as well as on optimizing its cross-section. In the supersonic flow, flow coefficients and local drop coefficients of the valve are dependent on several parameters, including fluid flow rate.

Sign in / Sign up

Export Citation Format

Share Document