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Article
Publication date: 1 October 2004

Jaw‐Ren Lin, Rong‐Fang Lu and Won‐Hsion Liao

The analysis of squeeze‐film performances between curved annular plates with an electrically conducting fluid in the presence of a transverse magnetic field is presented…

Abstract

The analysis of squeeze‐film performances between curved annular plates with an electrically conducting fluid in the presence of a transverse magnetic field is presented in this study. The magneto‐hydrodynamic (MHD) Reynolds‐type equation for squeezing‐film curved annular disks is derived using the continuity equation and the MHD motion equations. A closed‐form solution for the squeezing film pressure is obtained, and applied to predict the MHD squeeze‐film characteristics. According to the results obtained, the presence of applied magnetic fields signifies an increase in the MHD squeeze‐film pressure. Compared with the classical non‐conducting‐lubricant case, the magnetic‐field effect characterized by the Hartmann number provides an enhancement to the MHD load‐carrying capacity and the response time, especially for larger values of the curved shape parameter or smaller values of inner‐outer radius ratio of the curved annular disks.

Details

Industrial Lubrication and Tribology, vol. 56 no. 5
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 1 February 2005

Won‐Hsion Liao, Rong‐Fang Lu, Rean‐Der Chien and Jaw‐Ren Lin

The purpose of the present study is to provide the dynamic characteristics of long journal bearings lubricated with couple stress fluids.

Abstract

Purpose

The purpose of the present study is to provide the dynamic characteristics of long journal bearings lubricated with couple stress fluids.

Design/methodology/approach

Based upon the micro‐continuum theory generated by Stokes, the dynamic Reynolds‐type equation governing the film pressure is derived to account for the couple stress effects resulting from the non‐Newtonian behavior of complex fluids. By applying the linear stability theory to the non‐linear equations of motion the journal rotor, the equilibrium positions and dynamic characteristics of the system are evaluated.

Findings

As compared to the classical Newtonian model, the effects of couple stresses signify enhanced stiffness and damping coefficients (including KXX, KXY , BXX and BXY) at moderate values of the steady eccentricity ratio. Totally, as the rotor center operates at an eccentricity ratio about εs≤0.71, long bearings lubricated with couple stress fluids under small disturbance results in a higher stability threshold speed than that of the Newtonian‐lubricant case.

Originality/value

These findings provide engineers useful information in designing journal‐bearing systems.

Details

Industrial Lubrication and Tribology, vol. 57 no. 1
Type: Research Article
ISSN: 0036-8792

Keywords

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Article
Publication date: 16 September 2013

Jaw-Ren Lin, Rong-Fang Lu, Li-Ming Chu and Chi-Ren Hung

– The purpose of this paper is to investigate the effects of non-Newtonian rheology on the dynamic characteristics of a secant-shaped couple-stress lubricated slider bearing.

Abstract

Purpose

The purpose of this paper is to investigate the effects of non-Newtonian rheology on the dynamic characteristics of a secant-shaped couple-stress lubricated slider bearing.

Design/methodology/approach

By applying the linear dynamic theory to the film force equation, a closed-form solution of the stiffness and damping coefficients is obtained for the secant-shaped bearing taking into account the non-Newtonian effects of Stokes couple stress fluids.

Findings

Comparing with the secant-shaped Newtonian-lubricant bearing, the effects of non-Newtonian couple stresses provide an apparent improvement in the dynamic stiffness and damping characteristics, especially for the secant-shaped slider bearing operating at lower squeezing-film heights and with larger non-Newtonian couple stress parameters.

Originality/value

Comparing with those of the inclined plane-shaped non-Newtonian slider bearings, better dynamic stiffness and damping performances are provided for the secant-shaped non-Newtonian slider bearing designed at larger values of the shoulder parameters. The advantages of secant-shaped slider-bearing types provide engineers useful information in bearing selection and engineering application.

Details

Industrial Lubrication and Tribology, vol. 65 no. 6
Type: Research Article
ISSN: 0036-8792

Keywords

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Article
Publication date: 8 April 2014

Jaw-Ren Lin and Rong-Fang Lu

The aim of this study is to extend the squeezing film problems between a long cylinder and an infinite plate, considering the piezo-viscous behavior (PVB) of the Barus…

Abstract

Purpose

The aim of this study is to extend the squeezing film problems between a long cylinder and an infinite plate, considering the piezo-viscous behavior (PVB) of the Barus experimental relationship.

Design/methodology/approach

By integrating the nonlinear Reynolds-type differential equation directly, an analytical film-pressure solution is obtained and applied to investigate the load-carrying capacity and the approaching time.

Findings

Compared with the case of constant-viscosity lubricants (CVLs), the effects of PVB are found to provide higher load-carrying capacities and longer approaching times for the squeezing films.

Originality/value

It is found that when the cylinder is squeezed to a dimensionless central film height of 0.3, the dimensionless approaching time required for the CVL case is 4.922. However, the effects of PVB (α 0.0001, 0.001, 0.005 and 0.01) provide longer approaching times with values of 8.324, 8.438, 9.028 and 10.079. The cylinder-plate squeeze film system considering the influences of PVB results in a longer operating life.

Details

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

Keywords

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Article
Publication date: 1 December 2004

Jaw‐Ren Lin, Rong‐Fang Lu, Won‐Hsion Liao and Chia‐Chuan Kuo

A theoretical study of the combined effects of non‐Newtonian couple stresses and fluid inertia forces on the squeeze‐film behaviors for parallel circular plates is…

Abstract

A theoretical study of the combined effects of non‐Newtonian couple stresses and fluid inertia forces on the squeeze‐film behaviors for parallel circular plates is presented in this paper. Based upon the micro‐continuum theory, the Stokes constitutive equations are used to account for the couple stress effects resulting from the lubricant blended with various additives. The convective inertia forces included in the momentum equation are approximated by the mean value averaged across the fluid film thickness. Numerical solutions for the squeezing film characteristics are presented for various values of couple stress parameter and Reynolds number. Comparing with the classical Newtonian non‐inertia flow, the combined effects of couple stresses and convective inertia forces result in a larger load‐carrying capacity and therefore, increase the response time of the squeezing film plates.

Details

Industrial Lubrication and Tribology, vol. 56 no. 6
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 4 February 2014

Shyh-Rong Fang, Enchi Chang, Chueh-Chu Ou and Chia-Hui Chou

The purposes of this paper are to examine whether internal market orientation facilitates the development of external market capabilities, before influencing…

Abstract

Purpose

The purposes of this paper are to examine whether internal market orientation facilitates the development of external market capabilities, before influencing organizational performance, and to investigate whether learning orientation strengthens the aforementioned link.

Design/methodology/approach

This study collected data through a survey and utilized moderated hierarchical regression analysis to examine the hypothesized relationships.

Findings

Internal market orientation facilitates the development of both market capabilities and in turn enhances organizational performance. The result also shows that customer-linking capability is a stronger mediator between internal market orientation and organizational performance. Besides, learning orientation does not moderate the relationship between internal market orientation and external market capabilities.

Research limitations/implications

This study only examines two market capabilities; considers only internal market orientation and does not include other antecedents; and used cross-sectional data, instead of longitudinal data, which consist of information only from 159 services companies in Taiwan.

Practical implications

A company should have international market orientation mechanisms, such as internal market information system and reward systems to keep the internal communications open. For companies stressing external customer relationship, internal marketing is important.

Originality/value

This study provides empirical evidence for the claim that internal marketing influences the formation of an organization's external market capabilities. It also considers two types of market capabilities instead of treating market capabilities as a holistic variable. This study also clarifies learning orientation's relationships with internal market orientation and market capabilities.

Details

European Journal of Marketing, vol. 48 no. 1/2
Type: Research Article
ISSN: 0309-0566

Keywords

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