Impact of neglecting the variations in the relative surface roughnesses of capillary tubes on the accuracy of a capillary tube model

2021 ◽  
Author(s):  
Luka Lorbek ◽  
Tomaž Katrašnik ◽  
Andrej Kitanovski
Keyword(s):  
Capillary Tube ◽  
Tube Model ◽  
Capillary Tubes ◽  
Capillary Tube Model

Adiabatic Capillary Tube Model for a Carbon Dioxide Transcritical Cycle

2015 ◽  
Vol 23 (02) ◽  
pp. 1550011 ◽  
Author(s):  
R. O. Nunes ◽  
R. N. Faria ◽  
N. Bouzidi ◽  
L. Machado ◽  
R. N. N. Koury
Keyword(s):  
Experimental Data ◽  
Carbon Dioxide ◽  
Mathematical Model ◽  
Mass Flow ◽  
Flow Condition ◽  
Capillary Tube ◽  
Tube Model ◽  
Minimum Diameter ◽  
Conservation Of Energy ◽  
Capillary Tube Model

This paper presents a mathematical model for a capillary tube using CO 2 as fluid in steady flow transcritical cycle. The capillary tube is divided into N volumes controls and the model is based on applying the equations of conservation of energy, mass and momentum in the fluid in each of these volumes controls. The model calculates the mass flow of the CO 2 in the capillary tube as a function of CO 2 pressures at the inlet and outlet of the capillary and the temperature of CO 2 at the input of this device. The capillary tube is considered to be adiabatic, and the limit of operation due to blocked flow condition is also considered in the model. The validation of the model was performed with experimental data and the results showed that the model is capable of predicting the mass flow in the capillary tube with errors less than 10%. The model was also used to determine the minimum diameter of the capillary tube for various conditions of CO 2 transcritical cycle.

Two-Phase Fluid Flow Characterizations in a Tight Rock: A Fractal Bundle of the Capillary Tube Model

2019 ◽  
Vol 58 (45) ◽  
pp. 20806-20814 ◽  
Author(s):  
Ying Li ◽  
Haitao Li ◽  
Shengnan Chen ◽  
Qirui Ma ◽  
Chang Liu
Keyword(s):  
Fluid Flow ◽  
Capillary Tube ◽  
Tube Model ◽  
Two Phase ◽  
Capillary Tube Model ◽  
Phase Fluid

scholarly journals Fractal Analysis of Microscale and Nanoscale Pore Structures in Carbonates Using High-Pressure Mercury Intrusion

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Fuyong Wang ◽  
Peiqing Lian ◽  
Liang Jiao ◽  
Zhichao Liu ◽  
Jiuyu Zhao ◽  
...  
Keyword(s):  
High Pressure ◽  
Capillary Tube ◽  
Fractal Dimensions ◽  
Tube Model ◽  
Permeability Model ◽  
Mercury Intrusion ◽  
Fractal Models ◽  
Capillary Tube Model ◽  
Fractal Characteristics ◽  
Nanoscale Pore

This paper investigated fractal characteristics of microscale and nanoscale pore structures in carbonates using High-Pressure Mercury Intrusion (HPMI). Firstly, four different fractal models, i.e., 2D capillary tube model, 3D capillary tube model, geometry model, and thermodynamic model, were used to calculate fractal dimensions of carbonate core samples from HPMI curves. Afterwards, the relationships between the calculated fractal dimensions and carbonate petrophysical properties were analysed. Finally, fractal permeability model was used to predict carbonate permeability and then compared with Winland permeability model. The research results demonstrate that the calculated fractal dimensions strongly depend on the fractal models used. Compared with the other three fractal models, 3D capillary tube model can effectively reflect the fractal characteristics of carbonate microscale and nanoscale pores. Fractal dimensions of microscale pores positively correlate with fractal dimensions of the entire carbonate pores, yet negatively correlate with fractal dimensions of nanoscale pores. Although nanoscale pores widely develop in carbonates, microscale pores have greater impact on the fractal characteristics of the entire pores. Fractal permeability model is applicable in predicting carbonate permeability, and compared with the Winland permeability model, its calculation errors are acceptable.

A capillary-tube model for two-phase transient flow through bentonite materials

2007 ◽  
Vol 44 (12) ◽  
pp. 1446-1461 ◽  
Author(s):  
Greg Siemens ◽  
James A. Blatz ◽  
Douglas Ruth
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Unsaturated Soils ◽  
Transient Flow ◽  
Capillary Tube ◽  
High Plasticity ◽  
Tube Model ◽  
Capillary Tube Model ◽  
Flow Through

Swelling mechanisms occurring on the pore scale or at the molecular level of high plasticity, unsaturated soils often control macroscopic behaviour. In this paper, a new capillary tube model is proposed. The model is used to represent laboratory-scale infiltration tests on a bentonite-rich soil. The goal is to develop a greater understanding of bulk behaviour by closely examining microscopic behaviour. A decrease in hydraulic conductivity with increasing water content has been observed in laboratory studies on flow through shrink–swell materials. The proposed mechanism causing a decrease in conductivity is a change in pore-size distribution. The unique feature of the new capillary-tube model is that, as water flows down the tube, the tube’s cross-sectional area contracts to restrict flow, thus representing the change in pore-size distribution observed in the physical tests. Flow data from the capillary tube are used to model the laboratory results, and new insight is gained into bulk flow behaviour. Finally, a comparison with a three-dimensional network model for bentonite-coated sand mixtures is presented.

scholarly journals Using BIB-SEM Imaging for Permeability Prediction in Heterogeneous Shales

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-19 ◽  
Author(s):  
C. J. A. Sinn ◽  
J. Klaver ◽  
R. Fink ◽  
M. Jiang ◽  
J. Schmatz ◽  
...  
Keyword(s):  
Capillary Tube ◽  
Pore Space ◽  
Ion Beam ◽  
Tube Model ◽  
Three Samples ◽  
Capillary Tube Model ◽  
Order Of Magnitude ◽  
Sem Imaging ◽  
2D Data ◽  
Newark Basin

Organic-rich shale samples from a lacustrine sedimentary sequence of the Newark Basin (New Jersey, USA) are investigated by combining Broad Ion Beam polishing with Scanning Electron Microscopy (BIB-SEM). We model permeability from this 2D data and compare our results with measured petrophysical properties. Three samples with total organic carbon (TOC) contents ranging from 0.7% to 2.9% and permeabilities ranging from 4 to 160 nD are selected. Pore space is imaged at high resolution (at 20,000x magnification) and segmented from representative BIB-SEM maps. Modeled permeabilities, derived using the capillary tube model (CTM) on segmented pores, range from 2.3 nD to 310 nD and are relatively close to measured intrinsic permeabilities. SEM-visible porosities range from 0.1% to 1.8% increasing with TOC, in agreement with our measurements. The CTM predicts permeability correctly within one order of magnitude. The results of this work demonstrate the potential of 2D BIB-SEM for calculating transport properties of heterogeneous shales.

Hydraulic conductivity in surface active soils

Soil Research ◽  
1976 ◽  
Vol 14 (2) ◽  
pp. 121 ◽  
Author(s):  
P Basak ◽  
MR Madhav
Keyword(s):  
Pore Water ◽  
Capillary Tube ◽  
Bound Water ◽  
Water Structure ◽  
Free Water ◽  
Tube Model ◽  
Fine Grained ◽  
Capillary Tube Model ◽  
Constant Viscosity ◽  
Surface Active

Kozeny's equation based on a capillary tube model with constant viscosity does not give satisfactory results for fine-grained soils. When surface forces dominate over gravity forces, the pore water behaves abnormally and the physical properties of this pore water are found to be quite different from free water. Flow through saturated fine-grained soils is known to be affected by the properties and thickness of loosely and strongly bound water, whose viscosity is observed to be higher because of the modified water structure induced by clay-water interaction. An analytical solution based on a capillary tube model taking into account the changed viscosity of bound water and variation of viscosity within the bound water in relation to its thickness is attempted. The derived equation appears to be general in nature and is applicable for both surface active and inactive soils. It is shown that Kozeny's equation turns out to be the particular case of the derived equation when the thickness of the bound water is zero or when the variation of viscosity is not taken into account.

scholarly journals Gold Nanoparticles Affect Pericyte Biology and Capillary Tube Formation

Pharmaceutics ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 738
Author(s):  
Sasikarn Looprasertkul ◽  
Amornpun Sereemaspun ◽  
Nakarin Kitkumthorn ◽  
Kanidta Sooklert ◽  
Tewarit Sarachana ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Endothelial Cell ◽  
Mrna Expression ◽  
Capillary Tube ◽  
Quantitative Polymerase Chain Reaction ◽  
Tube Formation ◽  
Endothelial Cell Proliferation ◽  
Control Group ◽  
Capillary Tubes ◽  
Cell Functions

Gold nanoparticles (AuNPs) are used for diagnostic and therapeutic purposes, especially antiangiogenesis, which are accomplished via inhibition of endothelial cell proliferation, migration, and tube formation. However, no research has been performed on the effects of AuNPs in pericytes, which play vital roles in endothelial cell functions and capillary tube formation during physiological and pathological processes. Therefore, the effects of AuNPs on the morphology and functions of pericytes need to be elucidated. This study treated human placental pericytes in monoculture with 20 nm AuNPs at a concentration of 30 ppm. Ki-67 and platelet-derived growth factor receptor-β (PDGFR-β) mRNA expression was measured using real-time reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Cell migration was assessed by Transwell migration assay. The fine structures of pericytes were observed by transmission electron microscopy. In addition, 30 ppm AuNP-treated pericytes and intact human umbilical vein endothelial cells were cocultured on Matrigel to form three-dimensional (3D) capillary tubes. The results demonstrated that AuNPs significantly inhibited proliferation, reduced PDGFR-β mRNA expression, and decreased migration in pericytes. Ultrastructural analysis of pericytes revealed AuNPs in late endosomes, autolysosomes, and mitochondria. Remarkably, many mitochondria were swollen or damaged. Additionally, capillary tube formation was reduced. We found that numerous pericytes on 3D capillary tubes were round and did not extend their processes along the tubes, which resulted in more incomplete tube formation in the treatment group compared with the control group. In summary, AuNPs can affect pericyte proliferation, PDGFR-β mRNA expression, migration, morphology, and capillary tube formation. The findings highlight the possible application of AuNPs in pericyte-targeted therapy for antiangiogenesis.

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