A study of two-phase flow in monoliths using ultrafast single-slice X-ray computed tomography

2016 ◽  
Vol 86 ◽  
pp. 56-66 ◽  
Author(s):  
Thomas Schäfer ◽  
Christine Meitzner ◽  
Rüdiger Lange ◽  
Uwe Hampel
Keyword(s):  
Computed Tomography ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
X Ray ◽  
Single Slice ◽  
X Ray Computed

Experimental two-phase flow measurement using ultra fast limited-angle-type electron beam X-ray computed tomography

2009 ◽  
Vol 47 (3) ◽  
pp. 369-378 ◽  
Author(s):  
M. Bieberle ◽  
F. Fischer ◽  
E. Schleicher ◽  
D. Koch ◽  
H.-J. Menz ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Electron Beam ◽  
Flow Measurement ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
X Ray ◽  
X Ray Computed ◽  
Limited Angle

Ultrafast X-Ray Computed Tomography Imaging for Hydrodynamic Investigations of Gas–Liquid Two-Phase Flow in Centrifugal Pumps

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
Thomas Schäfer ◽  
Martin Neumann-Kipping ◽  
André Bieberle ◽  
Martina Bieberle ◽  
Uwe Hampel
Keyword(s):  
Computed Tomography ◽  
Gamma Ray ◽  
Two Phase Flow ◽  
Image Data ◽  
Phase Flow ◽  
Centrifugal Pumps ◽  
Two Phase ◽  
Pump Performance ◽  
X Ray ◽  
X Ray Computed

Abstract Gas entrainment into centrifugal pumps decreases pump performance and may raise safety issues, e.g., through insufficient cooling. Although there is some phenomenological knowledge in the form of correlations between operating parameters and pump performance, a further understanding via direct observation of the gas–liquid mixture was so far not possible. In this paper, we demonstrate the capability of ultrafast X-ray computed tomography (UFXCT) to disclose gas–liquid two-phase flow dynamics in the impeller region of a centrifugal pump mockup. Experiments were performed for gas injection at impeller speeds between 1300 rpm and 1600 rpm. We analyzed the X-ray image sequences with respect to characteristics of the gas distribution and compared them with time-averaged image data of a real pump obtained earlier with gamma-ray computed tomography (CT).

Imaging and Resistivity Studies of Saturation Gradients in Two-Phase Flow in 3-D Porous Media

1996 ◽  
Vol 464 ◽  
Author(s):  
E. H. Kawamoto ◽  
Po-Zen Wong
Keyword(s):  
Computed Tomography ◽  
Porous Media ◽  
Two Phase Flow ◽  
Water Saturation ◽  
Glass Beads ◽  
Water Phase ◽  
Phase Flow ◽  
Two Phase ◽  
Vertical Column ◽  
X Ray

ABSTRACTWe have carried out x-ray radiography and computed tomography (CT) to study two-phase flow in 3-D porous media. Air-brine displacement was imaged for drainage and imbibition experiments in a vertical column of glass beads. By correlating water saturation Sw with resistance R, we find that there is a threshold saturation S* ≈ 0.2, above which R(SW) ∼ Sw−2, in agreement with the empirical Archie relation. This holds true for both drainage and imbibition with littlehysteresis, provided that Sw remains above S*. Should Sw drop below S* during drainage, R(Sw) rises above the Archie prediction, exhibiting strong hysteresis upon reimbibition. This behavior suggests a transition in the connectivity of the water phase near S*, possibly due to percolation effects.

Pore Network Simulation of Two Phase Flow Based on X-Ray Micro Computed Tomography Images

2014 ◽  
Vol 960-961 ◽  
pp. 254-257 ◽  
Author(s):  
Meiheriayi Mutailipu ◽  
Yu Liu ◽  
Ling Yu Chen ◽  
Yong Chen Song
Keyword(s):  
Computed Tomography ◽  
Binary Data ◽  
Two Phase Flow ◽  
Network Simulation ◽  
Pore Network ◽  
Phase Flow ◽  
Micro Computed Tomography ◽  
Two Phase ◽  
X Ray ◽  
Pore Networks

In this paper, firstly, the X-ray micro computed tomography (micro-CT) is used for the analysis of internal structure of sand-packed beds. Binary data which are able to describe the pore structures of these beds were obtained from a series of imaging processing of rescaling, media filtering, and thresholding. Then a Maximal Ball (MB) algorithm is applied to these binary data to extract the equivalent pore networks. The parameters of the pore networks, such as radius, coordination number and shape factors of pore and throat are computed. The results demonstrate that the MB method can extract reasonable and faithful pore network of the different sand packed samples. Finally, the relative permeability and capillary pressure of drainage and imbibition cycle of water and oil are predicated. The numerical simulation results demonstrated good accordance with that of the experiments. Pore network simulation shows good results for two phase flow in porous media.

Application of Fast Synchrotron X-ray Imaging in Velocimetry of Cavitating Flows

2021 ◽  
Author(s):  
Mingming Ge ◽  
Guangjian Zhang ◽  
Navid Nematikourabbasloo ◽  
Kamel Fezzaa ◽  
Olivier Coutier-Delgosha
Keyword(s):  
Phase Contrast ◽  
Two Phase Flow ◽  
Motion Blur ◽  
Hydrodynamic Cavitation ◽  
Phase Flow ◽  
Two Phase ◽  
X Ray ◽  
Sheet Cavitation ◽  
Contraction Ratio ◽  
Wide Range

Hydrodynamic cavitation is a complex two-phase flow phenomenon involving mass and heat transfer between liquid and vapor. It occurs in many widely-used hydraulic machines, such as pumps and marine propellers, and often leads to undesired effects like material erosion, noise, and vibration. To control these detrimental effects, the visualization of two-phase flow morphology inside the opaque cavity is a crucial point to improve the physical and numerical models of cavitation. The major challenge in experimental measurements of cavitating flow fields is the fact that multiple scattering and a direct reflection of visible light from phase boundaries make the flow optically opaque. In recent years, unlike traditional local measurements using various probes, the development of the third-generation synchrotron radiation sources promotes the application of Xray phase-contrast imaging, which enables clear visualization of boundaries between phases with different refractive indices. In this study, the partial cavity is formed in a convergent-divergent (Venturi) channel with a small contraction ratio where the relatively stable cavitation regime can be sustained in a wide range of cavitation numbers. The experiment performed at Advanced Photon Source (APS) of Argonne uses the short high-flux X-ray pulses emitted from synchrotron sources to capture fast dynamic events and minimize motion blur. The internal two-phase structures and bubble development dynamics inside the quasi-stable sheet cavitation can be identified. Aside from the detailed illustration of two-phase morphology, X-ray phase-contrast images were also used to perform velocimetry by tracking either seeded particles or phase interfaces inside the opaque regions. Through appropriate postprocessing to the recorded X-ray images of cavitation, the time resolved velocity and void fraction fields are obtained simultaneously. These unprecedented experimental data will be further explored in understanding fluid mechanics underneath the cavity, estimating slip velocity between fluid-vapor interactions, and reconstructing pressure fields for compressible flows.

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