Stokes Slip Flow in Channel Bend

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
C. Y. Wang
Keyword(s):  
Exact Solution ◽  
Pressure Drop ◽  
Slip Flow ◽  
Velocity Slip ◽  
Meandering Channel ◽  
Channel Bend ◽  
Slip Factor ◽  
Small Ratio ◽  
Gap Width

Abstract Using intrinsic coordinates, the slip flow in a minute meandering channel is studied by perturbation about the small ratio of curvature to inverse half gap width. The exact solution for an annulus shows this ratio can be as large as 0.5 with less than 1% error. Velocity slip on the walls and the pressure drop depend on the slip factor. Formula for the pressure drop in a channel with a single bend is derived.

Effects of Axial Corrugated Roughness on Low Reynolds Number Slip Flow and Continuum Flow in Microtubes

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Zhipeng Duan ◽  
Y. S. Muzychka
Keyword(s):  
Pressure Drop ◽  
Slip Flow ◽  
Velocity Slip ◽  
Analytical Models ◽  
Axial Distance ◽  
Microchannel Flow ◽  
Compressibility Effect ◽  
Continuum Flow ◽  
Experimental Pressure ◽  
The Stokes Equation

The effect of axial corrugated surface roughness on fully developed laminar flow in microtubes is investigated. The radius of a microtube varies with the axial distance due to corrugated roughness. The Stokes equation is solved using a perturbation method with slip at the boundary. Analytical models are developed to predict friction factor and pressure drop in corrugated rough microtubes for continuum flow and slip flow. The developed model proposes an explanation on the observed phenomenon that some experimental pressure drop results for microchannel flow have shown a significant increase due to roughness. The developed model for slip flow illustrates the coupled effects between velocity slip and small corrugated roughness. Compressibility effect has also been examined and simple models are proposed to predict the pressure distribution and mass flow rate for slip flow in corrugated rough microtubes.

Slip Flow in Rectangular and Annular Ducts

1965 ◽  
Vol 87 (4) ◽  
pp. 1018-1024 ◽  
Author(s):  
W. A. Ebert ◽  
E. M. Sparrow
Keyword(s):  
Pressure Drop ◽  
Rarefied Gas ◽  
Slip Flow ◽  
Velocity Slip ◽  
Density Level ◽  
Axial Pressure ◽  
Slip Regime ◽  
Rarefied Gas Flows ◽  
Axial Pressure Gradient ◽  
Viscous Shear

An analysis has been performed to determine the velocity and pressure-drop characteristics of moderately rarefied gas flows in rectangular and annular ducts. The density level is such that a velocity slip may occur at the duct walls. In general, it is found that the effect of slip is to flatten the velocity distribution relative to that for a continuum flow; furthermore, the axial pressure gradient is diminished under slip-flow conditions. The conditions characterizing the onset of the slip regime have been determined on the basis of a 2 percent reduction in friction factor relative to the continuum value. For all the geometries studied here, the onset of slip occurred at a Knudsen number of 0.003. The effect of compressibility on the axial pressure drop was also investigated. It was found that compressibility increases the pressure drop primarily through an increase in viscous shear rather than through an increase in momentum flux.

scholarly journals Pressure Drop of Microchannel Plate Fin Heat Sinks

Micromachines ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 80 ◽  
Author(s):  
Zhipeng Duan ◽  
Hao Ma ◽  
Boshu He ◽  
Liangbin Su ◽  
Xin Zhang
Keyword(s):  
Fluid Dynamics ◽  
Pressure Drop ◽  
Slip Flow ◽  
Numerical Data ◽  
Velocity Slip ◽  
Fundamental Solutions ◽  
Momentum Equation ◽  
Channel Length ◽  
Microchannel Plate ◽  
Heat Sinks

The entrance region constitutes a considerable fraction of the channel length in miniaturized devices. Laminar slip flow in microchannel plate fin heat sinks under hydrodynamically developing conditions is investigated semi-analytically and numerically in this paper. The semi-analytical model for the pressure drop of microchannel plate fin heat sinks is obtained by solving the momentum equation with the first-order velocity slip boundary conditions at the channel walls. The simple pressure drop model utilizes fundamental solutions from fluid dynamics to predict its constitutive components. The accuracy of the model is examined using computational fluid dynamics (CFD) simulations and the experimental and numerical data available in the literature. The model can be applied to either apparent liquid slip over hydrophobic and superhydrophobic surfaces or gas slip flow in microchannel heat sinks. The developed model has an accuracy of 92 percent for slip flow in microchannel plate fin heat sinks. The developed model may be used to predict the pressure drop of slip flow in microchannel plate fin heat sinks for minimizing the effort and expense of experiments, especially in the design and optimization of microchannel plate fin heat sinks.

scholarly journals Discussion: “Slip-Flow Pressure Drop in Microchannels of General Cross Section”

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
C. Y. Wang
Keyword(s):  
Exact Solution ◽  
Fluid Flow ◽  
Pressure Drop ◽  
Cross Section ◽  
Dynamic Properties ◽  
Fluid Dynamic ◽  
Slip Flow ◽  
Partial Slip ◽  
Boundary Slip ◽  
Flow Pressure

Partial slip occurs in a variety of important fluid flow situations. Recently several sources used the constant boundary slip assumption for the flow in a tube. By comparing with the exact solution for the slip flow in a triangular duct, we show the constant slip assumption invokes substantial errors in both local and global fluid dynamic properties.

Effects of Corrugated Roughness on Developed Laminar Flow in Microtubes

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Zhipeng Duan ◽  
Y. S. Muzychka
Keyword(s):  
Pressure Drop ◽  
Laminar Flow ◽  
Slip Flow ◽  
Velocity Slip ◽  
Momentum Equation ◽  
Analytical Models ◽  
Microchannel Flow ◽  
Compressibility Effect ◽  
Continuum Flow ◽  
Experimental Pressure

The effects of corrugated surface roughness on developed laminar flow in microtubes are investigated. The momentum equation is solved using a perturbation method with slip at the boundary. Novel analytical models are developed to predict friction factor and pressure drop in corrugated rough microtubes for continuum flow and slip flow. The developed model proposes an explanation on the observed phenomenon that some experimental pressure drop results for microchannel flow have shown a significant increase (15–50%) due to roughness. The developed model for slip flow illustrates the coupled effects between velocity slip and small corrugated roughness. Compressibility effect has also been examined and simple models are proposed to predict the pressure distribution and mass flow rate for slip flow in corrugated rough microtubes.

Zero Mass Flux Dependent on Radiative Magnetohydrodynamics Carreau Nanofluid Over a Radially Surface with Temperature Jump and Slip Flow: A Hybrid Nanofluid Analysis

2021 ◽  
Vol 10 (1) ◽  
pp. 118-127
Author(s):  
Amit Parmar ◽  
Rakesh Choudhary ◽  
Krishna Agrawal
Keyword(s):  
Mass Flux ◽  
Temperature Jump ◽  
Slip Flow ◽  
Velocity Slip ◽  
Concentration Profiles ◽  
Fluid Temperature ◽  
Slip Parameter ◽  
First Order ◽  
Zero Mass ◽  
Carreau Nanofluid

The present study explores the slip flow and heat transfer induced by a radially surface with MHD Carreau nanofluid. In addition, the effects of temperature jump, non-linear radiation and the dependent zero mass flux also taken into account. This study also considers the cross-diffusion effect on temperature and concentration governing profiles. Appropriate transformations are engaged in order to acquire nonlinear differential equations (ODEs) from the partial differential system, their solutions are obtained by Runge-Kutta 4th order with shooting scheme in MATLAB. The impact of pertinent flow parameters such as first and second order velocity slip parameter, temperature jump, magnetic parameter, heat source, radiation parameter, melting surface parameter, temperature ratio parameter on dimensionless velocity, temperature and concentration profiles achieved graphically as well as local skin friction, Nusselt number and Sherwood number are demonstrated in the form of Table. first order velocity slip parameter (slip1) on f′, Θ and Φ profile fields. With an increment in the velocity slip first order parameter (slip1) we have perceived a fall in the momentum boundary layer and concentration profiles and a growth in the fluid temperature field.

Analysis of velocity slip flow in lubrication film of aerostatic guide way in micron scale

2017 ◽  
Vol 12 (2) ◽  
pp. 240
Author(s):  
Fangwei Ning ◽  
Wei Long ◽  
Shaohua Yang ◽  
Hao Pei
Keyword(s):  
Slip Flow ◽  
Velocity Slip ◽  
Lubrication Film

scholarly journals Gas Microflows in the Slip Flow Regime: A Critical Review on Convective Heat Transfer

2011 ◽  
Vol 134 (2) ◽  
Author(s):  
Stéphane Colin
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer ◽  
Flow Regime ◽  
Convective Heat ◽  
Temperature Jump ◽  
Numerical Models ◽  
Slip Flow ◽  
Velocity Slip ◽  
Constant Wall Temperature ◽  
Slip Flow Regime

Accurate modeling of gas microvection is crucial for a lot of MEMS applications (microheat exchangers, pressure gauges, fluidic microactuators for active control of aerodynamic flows, mass flow and temperature microsensors, micropumps, and microsystems for mixing or separation for local gas analysis, mass spectrometers, vacuum, and dosing valves…). Gas flows in microsystems are often in the slip flow regime, characterized by a moderate rarefaction with a Knudsen number of the order of 10−2–10−1. In this regime, velocity slip and temperature jump at the walls play a major role in heat transfer. This paper presents a state of the art review on convective heat transfer in microchannels, focusing on rarefaction effects in the slip flow regime. Analytical and numerical models are compared for various microchannel geometries and heat transfer conditions (constant heat flux or constant wall temperature). The validity of simplifying assumptions is detailed and the role played by the kind of velocity slip and temperature jump boundary conditions is shown. The influence of specific effects, such as viscous dissipation, axial conduction and variable fluid properties is also discussed.

Irreversibility and Thermo-Diffusion Effects on Unsteady Chemically Reactive Slip Flow Between Two Rotating Disks

2019 ◽  
Vol 141 (10) ◽  
Author(s):  
M. Ijaz Khan ◽  
Sumaira Qayyum ◽  
T. Hayat ◽  
M. Waqas ◽  
A. Alsaedi
Keyword(s):  
Slip Flow ◽  
Velocity Slip ◽  
Convergent Series ◽  
Heterogeneous Reactions ◽  
Bejan Number ◽  
Nonlinear Thermal Radiation ◽  
Slip Parameter ◽  
Rotating Disks ◽  
Diffusion Parameters ◽  
Homotopy Analysis

Abstract This paper aims to investigate the entropy generation in slip flow due to double rotating disks. Heat equation is formulated by considering effects of viscous dissipation, Joule heating and nonlinear thermal radiation. Brownian motion and thermophoresis effects of nanofluid are also discussed. Applied magnetic field is considered to be time dependent. Homogeneous–heterogeneous reactions are also studied. Von Karman transformations are used. Homotopy analysis method is implemented on system of equations for convergent series solutions. Influence of various flow parameters on entropy, Bejan number, velocity, temperature, Nusselt number, and skin friction is discussed through graphs and tables. Axial velocity decays for higher nonlinear mixed convection variable of temperature and velocity slip parameter. Temperature rises for larger thermal slip parameter and thermophoresis parameter. Entropy and Bejan number are increasing for higher estimation of homogeneous reaction parameter and diffusion parameters.

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