Numerical Simulation of Self-Induced Thermocapillary Flow for Non-Uniform Evaporating Meniscus in Capillary Tubes

2007 ◽  
Author(s):  
You-Rong Li ◽  
Bo Lan ◽  
Lan Peng ◽  
Ying-Jie Liu
Keyword(s):  
Numerical Simulation ◽  
Flow Pattern ◽  
Thermocapillary Convection ◽  
Capillary Tube ◽  
Control Volume ◽  
Thermal Boundary Condition ◽  
Thermocapillary Flow ◽  
Capillary Tubes ◽  
Volume Approximation ◽  
Liquid Vapor

A computational model was developed to describe self-induced thermocapillary convection for non-uniform evaporating meniscus in vertical capillary tubes, which was filled with ethanol, methanol or water. The diameters of capillary tubes ranged from 100 μm to 1000 μm. The direct numerical simulation using control volume approximation was used to investigate the thermocapillary flow in the liquid phase. Three types of distribution of the heat flux along the liquid-vapor meniscus interface were investigated for various Marangoni numbers, to characterize the flow pattern under conditions close to realistic operating parameters. The simulation shows that the flow pattern depends on the thermal boundary condition on the liquid-vapor meniscus interface and the Marangoni number, but is very insensitive to the buoyancy force for thermocapillary convection for non-uniform evaporating meniscus in the capillary tube with the radius ro<500μm.

Numerical Simulation of Capillary-Tube Behaviour Working With Pure and Mixed Refrigerants Under Adiabatic and Non-Adiabatic Flow Conditions

2001 ◽  
Author(s):  
O. García-Valladares ◽  
C. D. Pérez-Segarra ◽  
A. Oliva
Keyword(s):  
Capillary Tube ◽  
Control Volume ◽  
Fluid Dynamic ◽  
Computational Cost ◽  
Special Treatment ◽  
Flow Conditions ◽  
Governing Equations ◽  
Capillary Tubes ◽  
Step Method ◽  
Technical Literature

Abstract A detailed numerical method for analysing the thermal and fluid-dynamic behaviour of capillary tube expansion devices working with pure refrigerants and mixtures has been developed by means of a one-dimensional analysis of the governing equations (continuity, momentum and energy). Metastable both liquid and two-phase regions have been taken into account. The discretized governing equations are coupled using an implicit step by step method. In order to minimise computational cost, a special treatment has been implemented to solve the control volume that contains transition between regions and a special mesh distribution has been used. All the flow variables together with the thermophysical properties are evaluated at each point of the grid in which the domain is discretized. The numerical model allows analysis of aspects such as geometry, type of fluid, critical or non-critical flow conditions, metastable regions, adiabatic or non-adiabatic capillary tubes and transient aspects. The accuracy of the detailed simulation model is demonstrated by comparison with experimental data from the technical literature for adiabatic capillary tubes and also for concentric capillary tube-suction line heat exchanger.

Numerical Study of Oil Slug Mobilization in a Capillary Tube

2010 ◽  
Author(s):  
Yihe Zhang ◽  
Liming Dai ◽  
Junya Luo
Keyword(s):  
Numerical Simulation ◽  
Simulation Study ◽  
Pressure Difference ◽  
Capillary Tube ◽  
Numerical Study ◽  
Surface Shape ◽  
Simplified Model ◽  
Residual Oil ◽  
Capillary Tubes ◽  
Inner Surface

This research investigates the effects of pore dimensions and smoothness on the mobilization of residual oil trapped inside pore structures. A model of water-filled uniform capillary tube with an oil slug trapped inside is employed as a simplified model for numerical simulation study. Pressure difference between two ends of the tube is being measured. The influence of the inner surface shape of the tube is mostly considered in this research. Based on the measurements of the capillary tubes used in experiments, a sine curved shape is employed to represent the inner surface of the capillary tube. Series of results have been obtained from the simulation. According to the results, the pressure difference required to mobilize the oil slug is inversely proportional to the smoothness of the tube inner surface shape.

NUMERICAL SIMULATION FOR FLOW ANALYSIS IN NON-ADIABATIC CAPILLARY TUBES

2017 ◽  
Author(s):  
Hugo Augusto ◽  
Felipe Silva ◽  
Caio Vinicios Juvencio da Silva ◽  
Maycon Ferreira Silva ◽  
Leonardo José Cavalcante Vasconcelos
Keyword(s):  
Numerical Simulation ◽  
Flow Analysis ◽  
Capillary Tubes

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.

scholarly journals Numerical Simulation of Intrachamber Processes in the Power Plant

2021 ◽  
Vol 11 (11) ◽  
pp. 4990
Author(s):  
Boris Benderskiy ◽  
Peter Frankovský ◽  
Alena Chernova
Keyword(s):  
Numerical Simulation ◽  
Power Plant ◽  
Flow Structure ◽  
Power Plants ◽  
Control Volume ◽  
Conjugate Problem ◽  
Topological Features ◽  
Gas Dynamic ◽  
Calculation Results ◽  
Volume Method

This paper considers the issues of numerical modeling of nonstationary spatial gas dynamics in the pre-nozzle volume of the combustion chamber of a power plant with a cylindrical slot channel at the power plant of the mass supply surface. The numerical simulation for spatial objects is based on the solution conjugate problem of heat exchange by the control volume method in the open integrated platform for numerical simulation of continuum mechanics problems (openFoam). The calculation results for gas-dynamic and thermal processes in the power plant with a four-nozzle cover are presented. The analysis of gas-dynamic parameters and thermal flows near the nozzle cover, depending on the canal geometry, is given. The topological features of the flow structure and thermophysical parameters near the nozzle cap were studied. For the first time, the transformation of topological features of the flow structure in the pre-nozzle volume at changes in the mass channel’s geometry is revealed, described, and analyzed. The dependence of the Nusselt number in the central point of stagnation on the time of the power plants operation is revealed.

A modified approach for numerical simulation of capillary tube-suction line heat exchangers

2016 ◽  
Vol 102 ◽  
pp. 283-292 ◽  
Author(s):  
Matheus dos Santos Guzella ◽  
Luben Cabezas-Gómez ◽  
Luiz Gustavo Monteiro Guimarães ◽  
Cristiano Bigonha Tibiriçá
Keyword(s):  
Numerical Simulation ◽  
Heat Exchangers ◽  
Capillary Tube ◽  
Suction Line ◽  
Tube Suction
Sign in / Sign up

Export Citation Format

Share Document