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Article
Publication date: 27 June 2018

Dongju Chen, Lihua Dong, Ri Pan, Jinwei Fan and Qiang Cheng

The purpose of this study is to investigate the coupling effects of the velocity slip, rarefaction effect and effective viscosity of the gas film on the performance of the…

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Abstract

Purpose

The purpose of this study is to investigate the coupling effects of the velocity slip, rarefaction effect and effective viscosity of the gas film on the performance of the aerostatic guideway in micro-scale and improve the analysis precision of the static performance of aerostatic guideway.

Design/methodology/approach

The corresponding model of the gas film flow with consideration of the velocity slip, rarefaction effect and effective viscosity of the gas film in micro-scale is proposed. By solving the corresponding model, the bearing capacity and the stiffness of the aerostatic guideway are obtained through the pressure distributions of the air cavity. Through comparing the bearing capacity and the stiffness in different situations, the couple effects of the three factors are analyzed. Finally, the experimental results about the stiffness are obtained and the contrast between the simulation stiffness and the tested stiffness is achieved.

Findings

Through comparing the coupling effects of the micro scale factors under different conditions on the performance of the aerostatic guideway, it was found that when comparing the effects of a single factor, the effect of the first-order slip is the largest. When two factors are randomly combined, velocity slip and viscosity of the gas film is the largest, but these coupling effects are less than the effect of considering three factors simultaneously.

Originality/value

It is essential to consider the first-order velocity slip, the flow factor Q and the effective viscosity when analyzing the static performance of the aerostatic guideway in micro-scale. This makes studying the performance of the aerostatic guideway in micro-scale feasible and improves the machine’s accuracy.

Details

Industrial Lubrication and Tribology, vol. 70 no. 5
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 6 January 2012

R. Ellahi and M. Hameed

The purpose of this paper is to study the effects of nonlinear partial slip on the walls for steady flow and heat transfer of an incompressible, thermodynamically…

Abstract

Purpose

The purpose of this paper is to study the effects of nonlinear partial slip on the walls for steady flow and heat transfer of an incompressible, thermodynamically compatible third grade fluid in a channel. The principal question the authors address in this paper is in regard to the applicability of the no‐slip condition at a solid‐liquid boundary. The authors present the effects of slip, magnetohydrodynamics (MHD) and heat transfer for the plane Couette, plane Poiseuille and plane Couette‐Poiseuille flows in a homogeneous and thermodynamically compatible third grade fluid. The problem of a non‐Newtonian plane Couette flow, fully developed plane Poiseuille flow and Couette‐Poiseuille flow are investigated.

Design/methodology/approach

The present investigation is an attempt to study the effects of nonlinear partial slip on the walls for steady flow and heat transfer of an incompressible, thermodynamically compatible third grade fluid in a channel. A very effective and higher order numerical scheme is used to solve the resulting system of nonlinear differential equations with nonlinear boundary conditions. Numerical solutions are obtained by solving nonlinear ordinary differential equations using Chebyshev spectral method.

Findings

Due to the nonlinear and highly complicated nature of the governing equations and boundary conditions, finding an analytical or numerical solution is not easy. The authors obtained numerical solutions of the coupled nonlinear ordinary differential equations with nonlinear boundary conditions using higher order Chebyshev spectral collocation method. Spectral methods are proven to offer a superior intrinsic accuracy for derivative calculations.

Originality/value

To the best of the authors' knowledge, no such analysis is available in the literature which can describe the heat transfer, MHD and slip effects simultaneously on the flows of the non‐Newtonian fluids.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 22 no. 1
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 13 April 2015

Qiyin Lin, Zhengying Wei, Ning Wang and Wei Chen

The purpose of this paper is to study the influence of large-area texture/slip surface, especially the area and position of large-area texture surface on journal bearing…

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1472

Abstract

Purpose

The purpose of this paper is to study the influence of large-area texture/slip surface, especially the area and position of large-area texture surface on journal bearing, and improve the tribological performances of journal bearing.

Design/methodology/approach

A modified texture/slip numerical boundary condition with double parameters is presented and is applied onto the region where surface textures locate to represent the impact of actual texture/slip surface. A phase change condition is used to analyze cavitation phenomena.

Findings

The global/cumulative texture effect can be represented by applying texture/slip condition onto the region where it locates. The area and position of texture/slip surface would significantly affect the cavitation and load-carrying capacity. Texture/slip surface would not affect the pressure and load-carrying capacity when it locates at cavitation zone. The effect of texture/slip surface on load-carrying capacity would be beneficial if it locates at the pressure rise region, but its effect would be adverse if it locates at the pressure drop region. Well-designed texture/slip surface can improve tribological performances.

Originality/value

The developed texture/slip boundary condition can be a suitable and useful tool to analyze the effect of large-area texture/slip surface and especially to optimize the area and position of large-area texture surface. This approach can be complementary to conventional approach which is used to analyze the influence of textures’ real configurations and parameters.

Details

Industrial Lubrication and Tribology, vol. 67 no. 3
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 22 June 2020

A. Ali, Soma Mitra Banerjee and S. Das

The purpose of this study is to analyze an unsteady MHD Darcy flow of nonNewtonian hybrid nanoliquid past an exponentially accelerated vertical plate under the influence…

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34

Abstract

Purpose

The purpose of this study is to analyze an unsteady MHD Darcy flow of nonNewtonian hybrid nanoliquid past an exponentially accelerated vertical plate under the influence of velocity slip, Hall and ion slip effects in a rotating frame of reference. The fluids in the flow domain are assumed to be viscously incompressible electrically conducting. Sodium alginate (SA) has been taken as a base Casson liquid. A strong uniform magnetic field is applied under the assumption of low magnetic Reynolds number. Effect of Hall and ion-slip currents on the flow field is examined. The ramped heating and time-varying concentration at the plate are taken into consideration. First-order homogeneous chemical reaction and heat absorption are also considered. Copper and alumina nanoparticles are dispersed in base fluid sodium alginate to be formed as hybrid nanoliquid.

Design/methodology/approach

The model problem is first formulated in terms of partial differential equations (PDEs) with physical conditions. Laplace transform method (LTM) is used on the nondimensional governing equations for their closed-form solution. Based on these results, expressions for nondimensional shear stresses, rate of heat and mass transfer are also determined. Graphical presentations are chalked out to inspect the impacts of physical parameters on the pertinent physical flow characteristics. Numerical values of the shear stresses, rate of heat and mass transfer at the plate are tabulated for various physical parameters.

Findings

Numerical exploration reveals that a significant increase in the secondary flow (i.e. crossflow) near the plate is guaranteed with an augmenting in Hall parameter or ion slip parameter. MHD and porosity have an opposite effect on velocity component profiles for both types of nanoliquids. Result addresses that both shear stresses are strongly enhanced by the Casson effect. Also, hybrid nanosuspension in Casson fluid (sodium alginate) exhibits a lower rate of heat transfer than usual nanoliquid.

Social implications

This model may be pertinent in cooling processes of metallic infinite plate in bath and hybrid magnetohydrodynamic (MHD) generators, metallurgical process, manufacturing dynamics of nanopolymers, magnetic field control of material processing, synthesis of smart polymers, making of paper and polyethylene, casting of metals, etc.

Originality/value

The originality of this study is to obtain an analytical solution of the modeled problem by using the Laplace transform method (LTM). Such an exact solution of nonNewtonian fluid flow, heat and mass transfer is rare in the literature. It is also worth remarking that the influence of Hall and ion slip effects on the flow of nonNewtonian hybrid nanoliquid is still an open question.

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Article
Publication date: 4 December 2017

N. Nithyadevi, P. Gayathri and A. Chamkha

The paper aims to examine the boundary layers of a three-dimensional stagnation point flow of Al-Cu nanoparticle-suspended water-based nanofluid in an electrically…

Abstract

Purpose

The paper aims to examine the boundary layers of a three-dimensional stagnation point flow of Al-Cu nanoparticle-suspended water-based nanofluid in an electrically conducting medium. The effect of magnetic field on second-order slip effect and convective heating is also taken into account.

Design/methodology/approach

The thermophysical properties of alloy nanoparticles such as density, specific heat capacity and thermal conductivity are computed using appropriate formula. The non-linear parabolic partial differential equations are transformed to ordinary differential equations and solved by shooting technique.

Findings

The influence of compositional variation of alloy nanoparticle, nanoparticle concentration, magnetic effect, slip parameters and Biot number are presented for various flow characteristics. Interesting results on skin friction and Nusselt number are obtained for different composition of aluminium and copper.

Originality/value

A novel result of the analysis reveals that impact of magnetic field near the boundary is suppressed by the slip effect.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 27 no. 12
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 10 December 2018

A.A. Avramenko, N.P. Dmitrenko, I.V. Shevchuk, A.I. Tyrinov and V.I. Shevchuk

The paper aims to consider heat transfer in incompressible flow in a rotating flat microchannel with allowance for boundary slip conditions of the first and second order…

Abstract

Purpose

The paper aims to consider heat transfer in incompressible flow in a rotating flat microchannel with allowance for boundary slip conditions of the first and second order. The novelty of the paper encompasses analytical and numerical solutions of the problem, with the latter based on the lattice Boltzmann method (LBM). The analytical solution of the problem includes relations for the velocity and temperature profiles and for the Nusselt number depending on the rotation rate of the microchannel and slip velocity. It was demonstrated that the velocity profiles at high rotation rates transform from parabolic to M-shaped with a minimum at the channel axis. The temperature profiles tend to become uniform (i.e. almost constant). An increase in the channel rotation rate contributes to the increase in the Nusselt number. An increase in the Prandtl number causes a similar effect. The trend caused by the effect of the second-order slip boundary conditions depends on the closure hypothesis. It is shown that heat transfer in a flat microchannel can be successfully modeled using the LBM methodology, which takes into account the second-order boundary conditions.

Design/methodology/approach

The paper is based on the comparisons of an analytical solution and a numerical solution, which employs the lattice Boltzmann method. Both mathematical approaches used the first-order and second-order slip boundary conditions. The results obtained using both methods agree well with each other.

Findings

The analytical solution of the problem includes relations for the velocity and temperature profiles and for the Nusselt number depending on the rotation rate of the microchannel and slip velocity. It was demonstrated that the velocity profiles at high rotation rates transform from parabolic to M-shaped with a minimum at the channel axis. The temperature profiles tend to become uniform (i.e. almost constant). The increase in the channel rotation rate contributes to the increase in the Nusselt number. An increase in the Prandtl number causes the similar effect. The trend caused by the effect of the second-order slip boundary conditions depends on the closure hypothesis. It is shown that heat transfer in a flat microchannel can be successfully modeled using the LBM methodology, which considers the second-order boundary conditions.

Originality/value

The novelty of the paper encompasses analytical and numerical solutions of the problem, whereas the latter are based on the LBM.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 5
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 2 October 2020

Jian Jin, Xiaochao Chen, Yiyang Fu and Yinhui Chang

This work aims to explore the combined effects of boundary slip and texturing on hydrodynamic journal bearings and identifies optimized slip and texture patterns to…

Abstract

Purpose

This work aims to explore the combined effects of boundary slip and texturing on hydrodynamic journal bearings and identifies optimized slip and texture patterns to improve the performance of journal bearings.

Design/methodology/approach

The quadratic programming technique is used to study the influence of boundary slip on the lubrication performance of a two-dimensional journal bearing. A numerical model is used to analyze the effect of the cylindrical texture shape on the characteristics of journal bearings. It is concluded that the combination of slip and texture can be an effective approach to improve the performance of hydrodynamic journal bearings.

Findings

The results show that there is an interfacial shear stress (perfect slip surface) and that the role of the slip regime is to reduce friction. Numerical analyses indicate that the location and size of the slip and texture zone have a large effect on journal bearings. A comparison of the distribution forms of various texture–slip combinations indicates that the full texture–slip combination can prominently reduce the load-carrying capacity and that the “forward-slip backward-texture” configuration can considerably improve the performance of journal bearings.

Originality/value

The combined effects of boundary slip and texture on hydrodynamic journal bearings are meticulously examined. The patterns of the slip and texture are optimized, which can substantially improve the journal bearing performance.

Details

Industrial Lubrication and Tribology, vol. 73 no. 2
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 28 May 2020

Mahantesh M. Nandeppanavar, M.C. Kemparaju, R. Madhusudhan and S. Vaishali

The steady two-dimensional laminar boundary layer flow, heat and mass transfer over a flat plate with convective surface heat flux was considered. The governing nonlinear…

Abstract

Purpose

The steady two-dimensional laminar boundary layer flow, heat and mass transfer over a flat plate with convective surface heat flux was considered. The governing nonlinear partial differential equations were transformed into a system of nonlinear ordinary differential equations and then solved numerically by Runge–Kutta method with the most efficient shooting technique. Then, the effect of variable viscosity and variable thermal conductivity on the fluid flow with thermal radiation effects and viscous dissipation was studied. Velocity, temperature and concentration profiles respectively were plotted for various values of pertinent parameters. It was found that the momentum slip acts as a boost for enhancement of the velocity profile in the boundary layer region, whereas temperature and concentration profiles decelerate with the momentum slip.

Design/methodology/approach

Numerical Solution is applied to find the solution of the boundary value problem.

Findings

Velocity, heat transfer analysis is done with comparing earlier results for some standard cases.

Originality/value

100

Details

Multidiscipline Modeling in Materials and Structures, vol. 16 no. 5
Type: Research Article
ISSN: 1573-6105

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Article
Publication date: 23 November 2018

K. Ramesh and Sartaj Ahmad Eytoo

The purpose of this paper is to investigate the three fundamental flows (namely, both the plates moving in opposite directions, the lower plate is moving and other is at…

Abstract

Purpose

The purpose of this paper is to investigate the three fundamental flows (namely, both the plates moving in opposite directions, the lower plate is moving and other is at rest, and both the plates moving in the direction of flow) of the Ree-Eyring fluid between infinitely parallel plates with the effects of magnetic field, porous medium, heat transfer, radiation and slip boundary conditions. Moreover, the intention of the study is to examine the effect of different physical parameters on the fluid flow.

Design/methodology/approach

The mathematical modeling is performed on the basis of law of conservation of mass, momentum and energy equation. The modeling of the present problem is considered in Cartesian coordinate system. The governing equations are non-dimensionalized using appropriate dimensionless quantities in all the mentioned cases. The closed-form solutions are presented for the velocity and temperature profiles.

Findings

The graphical results are presented for the velocity and temperature distributions with the pertinent parameters of interest. It is observed from the present results that the velocity is a decreasing function of Hartmann number. Temperature increases with the increase of Ree-Eyring fluid parameter, radiation parameter and temperature slip parameter.

Originality/value

First time in the literature, the authors obtained closed-form solutions for the fundamental flows of Ree-Erying fluid between infinitely parallel plates with the effects of magnetic field, porous medium, heat transfer, radiation and slip boundary conditions. Moreover, the results of this paper are new and original.

Details

Multidiscipline Modeling in Materials and Structures, vol. 15 no. 2
Type: Research Article
ISSN: 1573-6105

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Article
Publication date: 19 November 2020

Yun-lei Wang, Jiu-hui Wu, Zhen-tao Li and Lu-shuai Xu

The purpose of this paper is to investigate the effect of slip position on the performance of liquid film seal.

Abstract

Purpose

The purpose of this paper is to investigate the effect of slip position on the performance of liquid film seal.

Design/methodology/approach

A mathematical model of liquid film seal with slip/no-slip surface was established based on the Navier slip model and JFO boundary condition. Liquid film governing equation was discretized by the finite difference method and solved by the SOR relaxation iterative algorithm and the effects of slip position on sealing performance are discussed.

Findings

The results indicate that boundary slip plays an important role in the overall performance of a seal and a reasonable arrangement of slip position can improve the steady-state performance of liquid film seal.

Originality/value

Based on the mathematical model, the optimal parameters for liquid film seal with boundary slip at groove are obtained. The results presented in this study are expected to provide a theoretical basis to improve the design method of liquid film seal.

Peer review

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-03-2020-0082/

Details

Industrial Lubrication and Tribology, vol. 73 no. 3
Type: Research Article
ISSN: 0036-8792

Keywords

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