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Article
Publication date: 27 August 2019

Muhammad Ijaz Khan, Ahmed Alsaedi, Salman Ahmad and Tasawar Hayat

This paper aims to examine squeezing flow of hybrid nanofluid inside the two parallel rotating sheets. The upper sheet squeezes downward, whereas the lower sheet…

Abstract

Purpose

This paper aims to examine squeezing flow of hybrid nanofluid inside the two parallel rotating sheets. The upper sheet squeezes downward, whereas the lower sheet stretches. Darcy’s relation describes porous space. Hybrid nanofluid consists of copper (Cu) and titanium oxide (TiO2) nanoparticles and water (H2O). Viscous dissipation and thermal radiation in modeling are entertained. Entropy generation analysis is examined.

Design/methodology/approach

Transformation procedure is implemented for conversion of partial differential systems into an ordinary one. The shooting scheme computes numerical solution.

Findings

Velocity, temperature, Bejan number, entropy generation rate, skin friction and Nusselt number are discussed. Key results are mentioned. Velocity field increases vs higher estimations of squeezing parameter, while it declines via larger porosity variable. Temperature of liquid particles enhances vs larger Eckert number. It is also examined that temperature field dominates for TiO2-H2O, Cu-H2O and Cu-TiO2-H2O. Magnitude of heat transfer rate and skin friction coefficient increase against higher squeezing parameter, radiative parameter, porosity variable and suction parameter.

Originality/value

The originality of this paper is investigation of three-dimensional time-dependent squeezing flow of hybrid nanomaterial between two parallel sheets. To the best of the authors’ knowledge, no such consideration has been carried out in the literature.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 9
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 11 January 2021

Mostafa Esmaeili, Hamed Hashemi Mehne and D.D. Ganji

This study aims to explore the idea of solving the problem of squeezing nanofluid flow between two parallel plates using a novel mathematical method.

Abstract

Purpose

This study aims to explore the idea of solving the problem of squeezing nanofluid flow between two parallel plates using a novel mathematical method.

Design/methodology/approach

The unsteady squeezing flow is a coupled fourth-order boundary value problem with flow velocity and temperature as the desired unknowns. In the first step, the conditions that guarantee the existence of a unique solution are obtained. Then following Green’s function-based approach, an iterative method for solving the problem is developed.

Findings

The accuracy of the method is examined by comparing the obtained results with existing numerical data, indicating excellent agreement between the two. In addition, the effects of nanoparticle shape and volume fraction on the flow and heat transfer characteristics are addressed. The results reveal that although the nanoparticle shape strongly affects the temperature distribution in the squeezing flow, it only has a slight impact on the velocity field. Furthermore, the highest and lowest Nusselt numbers belong to the platelets and spherical nanoparticles, respectively.

Originality/value

A semi-analytical method with computational support is developed for solving the unsteady squeezing flow problem. Moreover, the existence and uniqueness of the solution are discussed for the first time.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 31 no. 9
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 16 January 2019

Shitao Liu, Rong Cui, Hongwei Cao and Jinhong Qiu

This paper aims to show a resin-flowing model based on Darcy’s law to display the flowing properties of prepreg during lamination. The conformity between the model and…

Abstract

Purpose

This paper aims to show a resin-flowing model based on Darcy’s law to display the flowing properties of prepreg during lamination. The conformity between the model and experimental results demonstrates that it can provide a guideline on print circuit board (PCB) lamination.

Design/methodology/approach

Based on the theoretical derivations of Darcy’s law, this paper made an analysis on the flow of prepreg in the pressing process, according to which a theoretical model, namely, resin-flowing model was further formulated.

Findings

This paper establishes a resin-flowing model, according to which two experiment-verified conclusions can be drawn: first, the resin-flowing properties of material A and B can be improved when the heating rate is between 1.5 and 2.5 min/°C; second, increased pressure gradient can add the amount of flowing resin, mainly featured by increasing pressure and reducing filled thickness of prepreg.

Originality/value

This model provides guidance on setting lamination parameters for most kinds of prepregs and decreasing starvation risk for PCB production.

Details

Circuit World, vol. 45 no. 2
Type: Research Article
ISSN: 0305-6120

Keywords

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Article
Publication date: 8 April 2014

Neminath Bhujappa Naduvinamani and Mareppa Rajashekar

The purpose of this article is to analyse the effects of surface roughness on the magneto-hydrodynamic (MHD) squeeze-film characteristics between a sphere and a porous…

Abstract

Purpose

The purpose of this article is to analyse the effects of surface roughness on the magneto-hydrodynamic (MHD) squeeze-film characteristics between a sphere and a porous plane surface, which have not been studied so far.

Design/methodology/approach

The analytical model takes into account the effect of porosity by assuming that the flow in the porous matrix obeys modified Darcy's law. The stochastic MHD Reynold's type equation is derived by using the Christensen's stochastic method developed for hydrodynamic lubrication of rough surfaces. Two types of one-dimensional surface roughness (radial and azimuthal) patterns are considered.

Findings

The expressions for the mean MHD squeeze-film pressure and mean load-carrying capacity are obtained numerically. The results are shown graphically for selected representative parametric values. It is found that the response time increases significantly for the MHD case as compared to the corresponding non-conducting lubricants. The effect of roughness parameter is to increase/decrease the load-carrying capacity and the response time for azimuthal/radial roughness patterns as compared to the smooth case. Also, the effect of porous parameter is to decrease the load-carrying capacity and response time as compared to the solid case.

Originality/value

In this paper, an attempt has been made to analyse the combined effects of surface roughness and permeability on the MHD squeeze-film characteristics between a sphere and a plane surface.

Details

Industrial Lubrication and Tribology, vol. 66 no. 3
Type: Research Article
ISSN: 0036-8792

Keywords

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Article
Publication date: 1 April 2004

Chi‐Ren Hung, Long‐Jin Liang, Tong‐Bou Chang and Jaw‐Ren Lin

The influences of viscous shear stresses on the squeezing film behaviors in porous journal bearings with infinite length are analyzed. Based on the Brinkman model, two…

Abstract

The influences of viscous shear stresses on the squeezing film behaviors in porous journal bearings with infinite length are analyzed. Based on the Brinkman model, two general coupled Reynolds‐type equations derived between two curved surfaces are applied to evaluate the bearing characteristics. According to the results obtained, the Brinkman model predicts quite different squeezing film performances to those obtained by using the slip‐flow model and the Darcy model. In addition, the quantitative effects of viscous shear stresses of the Brinkman model upon the porous squeezing film characteristics are more pronounced for porous journal bearings with moderate permeability parameters and higher eccentricity ratios.

Details

Industrial Lubrication and Tribology, vol. 56 no. 2
Type: Research Article
ISSN: 0036-8792

Keywords

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Article
Publication date: 13 January 2021

Arshad Riaz, T. Abbas, A. Zeeshan and Mohammad Hossein Doranehgard

Entropy generation in nanofluids with peristaltic scheme occupies a primary consideration in the sense of its application in clinical, as well as the industrial field in…

Abstract

Purpose

Entropy generation in nanofluids with peristaltic scheme occupies a primary consideration in the sense of its application in clinical, as well as the industrial field in terms of improved thermal conductivity of the original fluid. Three-dimensional cylindrical configurations are the most realistic and commonly used geometries which incorporate most of the experimental equipment. In the current study, three-dimensional cylindrical enclosures have been assumed to receive the results of entropy generation occurring due to viscous dissipation, heat transfer of nanofluid and mass concentration of nanoparticles through peristaltic pumping. Applications of the study can be found in peristaltic micro-pumps and novel drug delivery mechanism in pharmacological engineering.

Design/methodology/approach

The equations of interest have been structured under physical constraints of lubrication theory and dimensionless strategy. Finalized relations involve highly complicated partial differential equations whose solutions are tabulated through some perturbation procedure and expression of pressure rise is manipulated by a numerical technique through built-in command NIntegrate on Mathematical tool “Mathematica.”

Findings

It is evaluated that entropy production goes linear with the greater magnitudes of Brownian motion but inverse characteristics have been sorted against thermophoresis factor.

Originality/value

To the best of authors’ knowledge, this study does not exist in literature yet and it contains a new innovative idea.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 31 no. 8
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 2 August 2018

V.S. Madalli, Siddharama Patil, Ayyappa Hiremath and Ramesh Kudenatti

This paper aims to present a detailed analysis to explore the various properties of non-Newtonian couple stress lubricants between parallel porous plates.

Abstract

Purpose

This paper aims to present a detailed analysis to explore the various properties of non-Newtonian couple stress lubricants between parallel porous plates.

Design/methodology/approach

With reference to the theories based on micro-continuum analysis, a non-linear, non-Newtonian Reynolds type equation is arrived. The closed form solutions obtained clearly indicate the changes in pressure, load bearing capacity and response time because of variation in viscosity of couple stress fluid.

Findings

It is observed that the viscosity variation factor greatly influences the change in pressure, load carrying capacity and squeezing time.

Originality/value

It is observed that the nature of lubricants with suitable additives greatly helps in overcoming the adverse effect because of porous surface. Reynolds type equation is analysed using appropriate boundary conditions. The expression for pressure distribution arrived at in turn leads to the analysis of load bearing capacity and response time.

Details

Industrial Lubrication and Tribology, vol. 70 no. 6
Type: Research Article
ISSN: 0036-8792

Keywords

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Article
Publication date: 26 August 2014

Sundarammal Kesavan, Ali J. Chamkha and Santhana Krishnan Narayanan

– The purpose of this paper is to consider magnetohydrodynamic (MHD) squeeze film characteristics between finite porous parallel rectangular plates with surface roughness.

Abstract

Purpose

The purpose of this paper is to consider magnetohydrodynamic (MHD) squeeze film characteristics between finite porous parallel rectangular plates with surface roughness.

Design/methodology/approach

Based upon the MHD theory, this paper analyzes the surface roughness effect squeeze film characteristics between finite porous parallel rectangular plates lubricated with an electrically conducting fluid in the presence of a transverse magnetic field.

Findings

It is found that the magnetic field effects characterized by the Hartmann number produce an increased value of the load carrying capacity and the response time as compared to the classical Newtonian lubricant case. The modified averaged stochastic Reynolds equation governing the squeeze film pressure is derived.

Research limitations/implications

The present study has considered both Newtonian fluids and non-Newtonian liquids.

Practical implications

The work represents a very useful source of information for researchers on the subject of MHD squeeze film with finite porous parallel rectangular plates lubricated with an electrically conducting fluid.

Originality/value

This paper is relatively original and illustrates the squeeze film characteristics between finite porous parallel rectangular plates with MHD effects.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 24 no. 7
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 28 April 2020

Umair Rashid and Haiyi Liang

In this article, we consider the magnetohydrodynamic (MHD) nanofluid flow over a rotating stretchable disk through porous medium. For porous medium, Darcy’s relation is…

Abstract

Purpose

In this article, we consider the magnetohydrodynamic (MHD) nanofluid flow over a rotating stretchable disk through porous medium. For porous medium, Darcy’s relation is used. It also encompassed the impact of nanoparticles shape on MHD nanofluid flow and heat transfer. The effect of thermal radiation and Joule heating is also being considered.

Design/methodology/approach

Three categories of nanoparticles are taken into deliberation, i.e. copper, silver and titanium oxide. The nanofluid is made of pure water and various types of sphere- and lamina-shaped nanoparticles. By using appropriate similarity transformation, the governing partial differential equations are transformed to ordinary one. The coupled ordinary differential equations system is tackled numerically by bvp4c method.

Findings

The impact of various pertinent parameters, i.e. solid volume fraction, Hartman number, thermal radiations parameter, Reynolds number, Eckert number, porosity parameter and ratio parameter, on flow and Nusselt number with a fixed value of Prandtl number at 6.2 is discussed in details. The obtained results are presented in the concluding section. The lamina shape of nanoparticles in silver-water performed an excellent role on temperature distribution. The heat transfer rate of lamina shape in copper-water was found to be greater in the system of flow regime.

Originality/value

The authors have discussed the shape effect of nanoparticles on MHD nanofluid flow over a rotating stretchable disk through porous medium using three categories of nanoparticles, such as copper, silver and titanium oxide. To the best of the authors’ knowledge, this is the first study on mass and heat transfer nanofluid flow and no such study is yet published in literature. A detailed mathematical analysis has also to be carried out to prove the regularity of model. The authors believe that the numerical results are original and have not been copied from any other sources.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 30 no. 12
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 13 October 2020

Shalini M. Patil, C.V. Vinay and Dinesh P.A.

The purpose of this paper is to study the amalgamated consequences of nonNewtonian fluid and permeability for nonporous journal spinning with constant tangential velocity…

Abstract

Purpose

The purpose of this paper is to study the amalgamated consequences of nonNewtonian fluid and permeability for nonporous journal spinning with constant tangential velocity inside a rough porous bearing.

Design/methodology/approach

The flow is assumed to have developed under low Reynolds number, and the flow is governed by reduced Navier–Stokes equations. Based on Stokes theory for couple-stress fluid, a closed form of nonNewtonian Reynolds equation is obtained. Finite difference based multigrid method is adopted to study the various parameters of journal bearings.

Findings

It is found that bearing attributes such as pressure distribution and weight carrying capacity are commanding for nonNewtonian couple-stress fluid compared to the classical Newtonian case.

Originality/value

The multigrid method for the Reynolds equation is used, which accelerates the convergence rate of the solution and is independent of the grid size. The effects of couple-stress fluid promote the enhanced pressure distribution in the fluid. Both increased weight bearing capacity and delayed squeezing time reduce the skin-friction and hence take longer time to come in contact with each other.

Peer review

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-02-2020-0051/

Details

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

Keywords

1 – 10 of 38