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.

Flow development in a model airway bronchus

1989 ◽  
Vol 207 ◽  
pp. 379-392 ◽  
Author(s):  
B. Snyder ◽  
D. E. Olson
Keyword(s):  
Boundary Layer ◽  
Cross Section ◽  
Flow Separation ◽  
Human Lung ◽  
Three Dimensional ◽  
Constant Flow ◽  
Local Flow ◽  
Flow Profiles ◽  
Flow Development ◽  
Flow Cross

Three-dimensional laminar flow profiles were measured at each of three axial stations downstream from the inlet of a slowly tapering tube of constant flow cross-section. It was found that strong inlet wall shear induces significant secondary swirl, whose downstream growth is initially consistent with an inviscid model of vorticity transfer. This secondary flow may act to retard the onset of local flow separation by convecting axial momentum into the boundary layer adjacent to the diverging wall of the tube. These observations could account for the similar geometric shape of major bronchial airways: the suppression of flow separation in pulmonary bifurcations would promote moire effective airway ventilation in the human lung.

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