A review on the analysis and experiment of fluid flow and mixing in micro-channels

2007 ◽  
Vol 21 (3) ◽  
pp. 536-548 ◽  
Author(s):  
Simon Jayaraj ◽  
Sangmo Kang ◽  
Yong Kweon Suh
Keyword(s):  
Fluid Flow ◽  
Micro Channels

scholarly journals Selective Transport of Airborne Microparticles Through Micro-channels Under Microgravity

2021 ◽  
Vol 33 (1) ◽  
Author(s):  
Monia Makhoul ◽  
Philippe Beltrame
Keyword(s):  
Numerical Simulation ◽  
Fluid Flow ◽  
Bifurcation Analysis ◽  
Metal Particles ◽  
Microgravity Environment ◽  
Ratchet Effect ◽  
Selective Transport ◽  
Microgravity Experiments ◽  
Particle Drift ◽  
Micro Channels

AbstractThis paper analyzes the possibility of obtaining the selective transport of microparticles suspended in air in a microgravity environment through modulated channels without net displacement of air. Using numerical simulation and bifurcation analysis tools, we show the existence of intermittent particle drift under the Stokes assumption of the fluid flow. The particle transport can be selective and the direction of transport is controlled only by the kind of pumping used. The selective transport is interpreted as a deterministic ratchet effect due to spatial variations in the flow and the particle drag. This ratchet phenomenon could be applied to the selective transport of metal particles during the short duration of microgravity experiments.

A Study on the Strength under Pressure of Micro Heat Exchanger

2006 ◽  
Vol 326-328 ◽  
pp. 265-268
Author(s):  
Taek Joon Son ◽  
Young Shin Lee
Keyword(s):  
Stainless Steel ◽  
Fluid Flow ◽  
Heat Exchanger ◽  
Structural Analysis ◽  
Thin Plate ◽  
Thin Plates ◽  
Micro Channel ◽  
Design Guideline ◽  
Micro Heat Exchanger ◽  
Micro Channels

The strength of micro heat exchanger under pressure is studied in this paper. Micro heat exchanger is made with brazing technology. It is constructed of stainless steel thin plates with micro channels and in/out port for fluid flow. Micro channels in thin plates are formed by etching and all parts including thin plates are joined by brazing. The study on the strength under pressure is performed by structural analysis. For structural analysis, one layer of micro heat exchanger body is considered. It is composed of thin plate with micro channel and brazing filler which is used to join thin plates. This paper shows the tendency of stress behavior and gives design guideline of micro heat exchanger.

Numerical Analysis on Flow Characteristics of Anti-Gravity Flow

2011 ◽  
Author(s):  
Yan Li ◽  
Shuchao Zhang ◽  
Ning Mei
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Fluid Flow ◽  
Flow Characteristics ◽  
Gravity Flow ◽  
Radius Of Curvature ◽  
Micro Channel ◽  
Subcooled Boiling ◽  
Evaporation Heat ◽  
Micro Channels

Fluid flow phenomena in micro channels received wide attention due to its high heat transfer coefficient. As a new technique in the field of micro channel phase-change heat transfer, anti-gravity flow can drive fluid flow by capillary force and create enhanced evaporation heat transfer conditions by promoting the formation of an extended meniscus in the three-phase contact-line region. Resulting from the circumferential discrepancy of degree of superheat, the radius of curvature of intrinsic meniscus decreases rapidly as liquid rising up, leading to the formation of capillary pressure gradient. With the increase of heat flux, subcooled boiling occurs and micro-bubble appears at the bottom of the fluted tube. Under the action of buoyancy and drag force, the bubble rises along the channel and at the same time grows continually for the presence of superheat until its break. This paper focuses on the numerical study of flow characteristics of anti-gravity flow in the micro channel and the influence of bubble under the subcooled boiling circumstance. The results shows that bubble plays a positive role in the formation of anti-gravity flow and the analytical expressions are presented for the rising velocity of liquid, the contact angle and the curvature of the intrinsic meniscus, which are all influenced by heat flux, superheat temperature and the geometric parameters of the channel.

Effects of Real Surface Roughness on Fluid Flow in Nanochannels

2010 ◽  
Author(s):  
Ali Kharazmi ◽  
Reza Kamali
Keyword(s):  
Molecular Dynamics ◽  
Surface Roughness ◽  
Fluid Flow ◽  
Computer Program ◽  
Md Simulation ◽  
Real Surface ◽  
Micro Channels

In the present study, a computer program based on a molecular dynamics scheme has been developed for simulating fluid flow in nano- and micro-channels with roughness. According to the previous studies of nanochannels flows, surface roughness has a great effect on the rheology of the flow. Therefore a more realistic surface roughness has been developed and its influence on the fluid flow has been investigated using Molecular Dynamics (MD) Simulation.

scholarly journals Overview of the innovative heat exchangers technologies

2020 ◽  
Vol XXIII (2) ◽  
pp. 32-36
Author(s):  
Avram Elena Rita
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Heat Exchangers ◽  
Micro Channels ◽  
Flow Processes ◽  
Military Applications ◽  
Flow Through ◽  
Heat And Fluid Flow ◽  
Resistance To Heat ◽  
Similitude Theory

The current paper analyzed the new trends and challenges in heat exchanger technologies. The progress of the studies on mini and micro devices used in industry are presented. Particular attention is paid to the heat exchangers used in marine and chemical industries where the resistance to heat transfer increases due to the fouling or scaling. In the industry, there are very important the reduction in the size of devices, and the micro heat exchangers, due to its variety of advantages offered, are well recognized for their higher performance. The applications of them are ranging from process control to military applications. New engineering approaches for modeling the heat and fluid flow processes in micro heat exchangers are analyzed in the present paper. One of these is based on the dimensional analysis and principles of similitude theory that allow the modeling of microscale systems using a physical system at the mini scale. There are identified constant relationships between dimensions permitting the analysis of the fluid flow through micro channels.

Friction Law for Bingham Fluid Flow in Channels of Arbitrary Cross-Section Shapes

2009 ◽  
Author(s):  
Mario F. Letelier ◽  
Dennis A. Siginer ◽  
Juan S. Stockle ◽  
Carlos Vera
Keyword(s):  
Fluid Flow ◽  
Friction Coefficient ◽  
Cross Section ◽  
Protein Separation ◽  
Bingham Fluid ◽  
Arbitrary Cross Section ◽  
Time Dependent ◽  
Bingham Model ◽  
Micro Channels ◽  
Rigorous Method

In many biomedical and industrial technological applications it is necessary to drive fluids that exhibit plastic or elasto-plastic behaviour. Particularly for cases in which fast results are demanded, or only small fluid samples are available, micro-channels are used. These normally have cross-section geometries determined by the manufacturing procedures and may be of square, rectangular, triangular and other shapes. In order to obtain the expected results, such as protein separation, particle concentrations, and the like, the rate of flow and time-dependent pattern of it must be carefully determined. In this paper it is presented an analytically rigorous method for calculating the friction coefficient in channels of arbitrary cross-section contours for plastic flow that may be conveniently described by the Bingham model. Results are presented for a variety of shapes and for different values of the yield stress.

A Simplified ‘Effective Circuit’ Fluid Flow Model for Forced Convection in Oblique Fin Configuration

2014 ◽  
Author(s):  
Nasi Mou ◽  
Poh Seng Lee ◽  
Saif A. Khan
Keyword(s):  
Fluid Flow ◽  
Mass Flow ◽  
Flow Model ◽  
Electrical Circuit ◽  
Flow Paths ◽  
Micro Channels ◽  
Discrete Flow ◽  
Actual Flow ◽  
The Difference ◽  
Full Domain

In this paper, a simplified ‘effective circuit’ fluid flow model is proposed to complement full-domain (geometry based) simulations of fluid flow in novel discrete oblique fin heat sinks. In the proposed model, the discrete flow paths are modeled as effective resistances, and the intersections between discrete flow paths are modeled as ‘nodes’. In an electrical circuit, the current of each branch can be derived from the current division rule, and hence the actual flow rates in the effective circuit are determined by the effective resistances. Simulink R2011b, a graphical extension to MATLAB for modeling and simulation of systems, is chosen to construct the equivalent circuit. The effective resistances are calculated using the well-known friction factor expressions for laminar flow in micro-channels. A full-domain geometry-based simulation is performed on CFX 14.0 serving as a benchmark for the developed ‘effective circuit’ fluid flow model. The results show that for a given total current value and mass flow rate, the difference of pressure drop over the whole heat sink between the simplified flow model and CFX simulation is within 13%. The mass flow distributions obtained from the simplified flow model and the CFX simulation exhibit a common distribution pattern. Interestingly, the simplified flow model is even able to capture flow migration — a distinctive phenomenon of flow in oblique fin geometries. We thus confirm the feasibility of the method of construction of our simplified ‘effective circuit’ fluid flow model.

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