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Article
Publication date: 10 August 2012

Li‐Ming Chu, Hsiang‐Chen Hsu, Jaw‐Ren Lin and Yuh‐Ping Chang

The purpose of this paper is to describe an inverse approach to estimate the pressure distribution, temperature distribution, and pressure‐viscosity index (z) in a thermal…

Abstract

Purpose

The purpose of this paper is to describe an inverse approach to estimate the pressure distribution, temperature distribution, and pressure‐viscosity index (z) in a thermal elastohydrodynamic lubrication (TEHL) line contact.

Design/methodology/approach

Once the film thickness is given, the pressure distribution can be calculated using the inverse approach. Subsequently, thermal expansivity and temperature‐viscosity coefficient of lubricant are given, and then the z is guessed initially. The Gauss‐Seidel iteration is employed to calculate the temperature distribution from the rheology, energy, and surface temperature equations. In order to increase the algorithm stability, the least‐squares method must be employed to calculate the optimum value of the z in the computational domain. Furthermore, the pressure‐viscosity index must be updated by the iteration method to calculate accurate temperature distribution and apparent viscosity until convergence.

Findings

This approach presents a smooth curve of the pressure and temperature distributions with the measurement error from the resolution in the film thickness measurement and z value. Furthermore, this approach still provides a superior solution in apparent viscosity, whereas the direct method provides a much larger error in apparent viscosity.

Originality/value

The paper describes an inverse approach to estimate the pressure distribution, temperature distribution, and pressure‐viscosity index in a TEHL line contact. This approach overcomes the problems of pressure and temperature rise fluctuations and generates accurate results of pressure and temperature distribution from a small number of measured points of film thickness, which also saves computing time. Furthermore, this approach still provides a superior solution in apparent viscosity.

Details

Industrial Lubrication and Tribology, vol. 64 no. 5
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 15 June 2015

Zhenyuan Tang and Decheng Wan

The jet impingement usually accompanying large interface movement is studied by the in-house solver MLParticle-SJTU based on the modified moving particle semi-implicit…

Abstract

Purpose

The jet impingement usually accompanying large interface movement is studied by the in-house solver MLParticle-SJTU based on the modified moving particle semi-implicit (MPS) method, which can provide more accurate pressure fields and deformed interface shape. The comparisons of the pressure distribution and the shape of free surface between the presented numerical results and the analytical solution are investigated. The paper aims to discuss these issues.

Design/methodology/approach

To avoid the instability in traditional MPS, a modified MPS method is employed, which include mixed source term for Poisson pressure equation (PPE), kernel function without singularity, momentum conservative gradient model and highly precise free surface detection approach. Detailed analysis on improved schemes in the modified MPS is carried out. In particular, three kinds of source term in PPE are considered, including: particle number density (PND) method, mixed source term method and divergence-free method. Two typical kernel functions containing original kernel function with singularity and modified kernel function without singularity are analyzed. Three kinds of pressure gradient are considered: original pressure gradient (OPG), conservative pressure gradient (CPG) and modified pressure gradient (MPG). In addition, particle convergence is performed by running the simulation with various spatial resolutions. Finally, the comparison of the pressure fields by the modified MPS and by SPH is presented.

Findings

The modified MPS method can provide a reliable pressure distribution and the shape of the free surface compared to the analytical solution in a steady state after the water jet impinging on the wall. Specifically, mixed source term in PPE can give a reasonable profile of the shape of free surface and pressure distribution, while PND method adopted in the traditional MPS is not stable in simulation, and divergence-free method cannot produce rational pressure field near the wall. Two kernel functions show similar pressure field, however, the kernel function without singularity is preferred in this case to predict the profile of free surface and pressure on the wall. The shape of free surface by CPG and MPG is agreement with the analytical solution, while a great discrepancy can be observed by OPG. The pressure peak by MPG is closer to the analytical solution than that by CPG, while the pressure distribution on the right hand side of the pressure peak by latter is better match with the analytical solution than that by former. Besides, fine spatial resolution is necessary to achieve a good agreement with analytical results. In addition, the pressure field by the modified MPS is also quite similar to that by SPH, and this can further validate the reliable of current modified MPS.

Originality/value

The present modified MPS appears to be a stable and reliable tool to deal with the impinging jet flow problems involving large interface movement. Mixed source term in PPE is superior to PND adopted in the traditional MPS and divergence-free method. The kernel function without singularity is preferred to improve the computational accuracy in this case. CPG is a good choice to obtain the shape of free surface and the pressure distribution by jet impingement.

Details

Engineering Computations, vol. 32 no. 4
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 10 June 2021

Chunxiao Jiao, Jianghai Xu, Donglin Zou, Na Ta and Zhushi Rao

The purpose of this paper is to study the flow field characteristics of the micro-scale textured bearing surfaces using the lattice Boltzmann method based on the…

Abstract

Purpose

The purpose of this paper is to study the flow field characteristics of the micro-scale textured bearing surfaces using the lattice Boltzmann method based on the microscopic dynamics of the fluid.

Design/methodology/approach

Considering the inertia effects and the micro-scale effects, the models of a single micro-scale texture unit cell with different shapes and different film thickness ratios are established. The influence of pressure difference between inlet and outlet of the unit cell on flow characteristics is studied.

Findings

The surface pressure distribution, flow patterns and pressure contours in the flow field are obtained. The results reveal that the pressure difference has a significant influence on the characteristics of the micro-textured flow field.

Originality/value

The results have certain guiding significance for further step investigation on microscopic lubrication mechanism of the water-lubricated polymer bearings.

Details

Industrial Lubrication and Tribology, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0036-8792

Keywords

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Article
Publication date: 11 June 2018

Haykel Marouani and Tarek Hassine

Pin-loaded hubs with fitted bush are used in industrial connector-type elements. They are subjected to varying radial forces leading to variable stress distribution. The…

Abstract

Purpose

Pin-loaded hubs with fitted bush are used in industrial connector-type elements. They are subjected to varying radial forces leading to variable stress distribution. The literature provides various pressure distribution expressions adapted essentially for symmetric geometries and fixed load condition (circular hubs, half-infinite geometries, axial load, tangential load, etc.). This study aims to take into account the geometrical conditions of industrial connector-type elements and presents a model for pressure distribution based only on geometric parameters, maximal pressure and contact angle value for the case of fit pin-loaded hub.

Design/methodology/approach

The finite element computation for the contact problem shows that the pressure distribution of the pin-loaded hub under various inclined forces (from 0° to 180°) is a parabolic distribution. This distribution can be defined by three parameters which are θA, θB and Pmax. The study assumes that the distribution is symmetric and that Pmax can be modeled using force F, hub radius R, hub thickness b and the half contact angle are θA.

Findings

The new proposal pressure distribution parameters are easy to identify. Even for the non-symmetric pressure distribution, the study denotes that the errors on evaluating θA and θB keep the analytical model still in good agreement with finite element computations.

Research limitations/implications

Only the neat fit case was studied.

Practical/implications

Pin-loaded joints are connector-type elements used in mechanical assemblies to connect any structural components and linkage mechanisms such as connecting rod ends of automotive or shear joints for aircraft structure.

Originality/value

The good correlation between finite element computations and model results shows the validity of the assumptions adopted here. Analytical fatigue models, based on this stress distribution, could be derived in view of a fatigue lifetime calculation on connecting hub. Friction, pin deformation and local plastic effects under pin-loading are the main phenomena to take into account to further enrich this model.

Details

World Journal of Engineering, vol. 15 no. 3
Type: Research Article
ISSN: 1708-5284

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Article
Publication date: 20 April 2018

Maurizio Faccio, Mauro Gamberi, Mojtaba Nedaei and Francesco Pilati

The purpose of this paper is to investigate the autoclave-pump pressured water distribution system. Pressured water is used in many manufacturing processes, as a raw…

Abstract

Purpose

The purpose of this paper is to investigate the autoclave-pump pressured water distribution system. Pressured water is used in many manufacturing processes, as a raw material or as a service fluid for different applications.

Design/methodology/approach

The performances and the total installation costs of such systems are strongly related to its design and to its decision variables definition. The authors first identify the independent variables (i.e. the decision variables) and the dependent variables of the system and, second, propose a techno-economic mathematical method able to determine its minimum installation cost with an integrated approach.

Findings

The trade-off between the autoclave installation costs versus the pump installation costs is demonstrated. A sensitive analysis of the cost of the system as function of its decision variables has been performed to propose a practical graphical analysis tools to proper design the integrated pump-autoclave pressured water distribution system.

Originality/value

Many previous researches focus only on the pump system optimization or in the tank system optimization without an integrated approach. The wide utilization in industry of the autoclave-pump pressured water distribution system together with the lack of similar contributions in this area enforces the value of this research.

Details

Journal of Engineering, Design and Technology, vol. 16 no. 3
Type: Research Article
ISSN: 1726-0531

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Article
Publication date: 2 July 2020

Haixia Li, Yongrong Wang and Zhian Chen

Graduated compression shaping pants (GCSPs) are shapewears sharing the same action mechanisms as medical compression stockings (MCSs), setting four stages of pressure on…

Abstract

Purpose

Graduated compression shaping pants (GCSPs) are shapewears sharing the same action mechanisms as medical compression stockings (MCSs), setting four stages of pressure on lower limbs that gradually decreasing from the ankle to the thigh root. They are claimed to be able to not only shaping bodies but also promoting blood circulation in legs. However, there are few studies on whether GCSPs perform the advertised functions and how effective GCSPs could be. The purpose of this paper is to explore and evaluate the pressure distribution and body-shaping effectivity of GCSPs.

Design/methodology/approach

The authors first select two graduated compression shaping pants (GCSPs-A, GCSPs-B) and a pair of professional shaping pants as the Controls. Then objective pressure test and 3D body scanning test are conducted. Finally, the pressure distribution and body-shaping effectivity are demonstrated by ORIGIN and MATLAB, compared with controls.

Findings

GCSPs-A perform significant body-shaping effectivity at the calf, thigh and thigh root, which are less effective than the Controls. The body-shaping effectivity of GCSPs-B is predicted weaker than GCSPs-A at the calf and thigh, while better at the thigh root. Both GCSPs-A and GCSPs-B show gradual pressure, which could be classified into Class I or II of MCSs. Comprehensively, GCSPs-A are superior than GCSPs-B.

Originality/value

In this paper, authors evaluate the pressure distribution and body-shaping effectivity of GCSPs, which could provide guidance for enterprises to further optimize and produce GCSPs, performing better functions that meet consumers' needs better.

Details

International Journal of Clothing Science and Technology, vol. 33 no. 2
Type: Research Article
ISSN: 0955-6222

Keywords

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Article
Publication date: 4 January 2021

Jianghong Zhao and Xin Li

Vortex grippers use tangential nozzles to form vortex flow and are able to grip a workpiece without any physical contact, thus avoiding any unintentional workpiece damage…

Abstract

Purpose

Vortex grippers use tangential nozzles to form vortex flow and are able to grip a workpiece without any physical contact, thus avoiding any unintentional workpiece damage. This study aims to use experimental and theoretical methods to investigate the effects of nozzle diameter on the performance.

Design/methodology/approach

First, various suction force-distance curves were developed to analyze the effects of nozzle diameter on the maximum suction force. This study determines the tangential velocity distribution on the workpiece surface by substituting the experimental pressure distribution data into simplified Navier-Stokes equations and then used these equations to analyze the effects on the flow field. Subsequent theoretical analysis of the distribution of pressure and circumferential velocity further validated the experimental results. Next, by rearranging these relationships, the study considered the effects of nozzle diameter on the inherent vortex gripper characteristics. In addition, this study developed various suction force-energy consumption curves to analyze the effects of nozzle diameter.

Findings

The results of this study indicated that the vortex gripper’s circumferential velocity and maximum suction force decrease with increasing nozzle diameter. Nozzle diameter did not significantly affect the inherent frequency of the vortex gripper-workpiece inertial system or the corresponding suspension stability of the workpiece. However, an increase in nozzle diameter did effectively increase the vortex gripper’s suspension region. Finally, as the nozzle diameter increased, the energy required to achieve the same maximum suction force decreased.

Originality/value

This study’s findings can enable optimization of nozzle design in emerging vortex gripper designs and facilitate informed selection among existing vortex grippers.

Details

Assembly Automation, vol. 41 no. 1
Type: Research Article
ISSN: 0144-5154

Keywords

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Article
Publication date: 1 May 1997

Zbigniew Polinski and Wlodzimierz Wieczlak

Presents an original method of measurement of pressures on the working surfaces of clothing presses. It has been found that the mechanical properties of linings have a…

Abstract

Presents an original method of measurement of pressures on the working surfaces of clothing presses. It has been found that the mechanical properties of linings have a significant effect on the pressure distribution. Based on theoretical assumptions, a manner of selection of the lining for a technological task has been determined. Results of the experiments have confirmed the correctness of the assumptions made. The pressure distribution charts obtained also permit estimation of the effect of constructional errors of clothing presses on their effectiveness, particularly in the technology of glue joints.

Details

International Journal of Clothing Science and Technology, vol. 9 no. 2
Type: Research Article
ISSN: 0955-6222

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Article
Publication date: 13 January 2020

Qiang Li, Yujun Wang, Shuo Zhang, Wei-Wei Xu, Lu Bai and Zhenbo Wang

Surface textures have been widely used in thrust bearings as a means of enhancing the tribological performance. The effect of textures with a spiral distribution on the…

Abstract

Purpose

Surface textures have been widely used in thrust bearings as a means of enhancing the tribological performance. The effect of textures with a spiral distribution on the lubrication characteristics of thrust bearings has not been fully covered. This paper aims to investigate and find the optimal structure and distribution parameters of textures with the maximum loading capacity and minimum friction force as goals.

Design/methodology/approach

Combining the multi-objective optimization method based on the non-dominated sorted genetic algorithm-II with response surface methodology, the key textured parameters are optimized. Local sensitivity analysis is used to evaluate the impact level of each parameter.

Findings

Spiral distribution of textures can effectively improve the lubrication performance of the thrust bearing compared with the linear distribution. The distribution with high amplitudes and high cycle numbers will weaken the spiral effect and destroy the high-pressure region. Through the multi-objective optimization of the textured structure and distribution parameters, the loading capacity demonstrates a 55.05per cent improvement compared to the basic model. Textured width is the most sensitive parameter for both loading capacity and friction force.

Originality/value

Present research provides a fundamental design guide for textured thrust bearings.

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Article
Publication date: 12 March 2018

K.R. Kadam and S.S. Banwait

Different groove angles are used to study performance characteristics of two-axial groove journal bearing. In this study two grooves are located at ±90º to the load line…

Abstract

Purpose

Different groove angles are used to study performance characteristics of two-axial groove journal bearing. In this study two grooves are located at ±90º to the load line. The various angles of grooves have been taken as 10° to 40° in the interval of 5°. Different equations such as Reynolds equation, three-dimensional energy equation and heat conduction equation have been solved using finite element method and finite difference method. Pressure distribution in fluid is found by using Reynolds equation. The three-dimensional energy equation is used for temperature distribution in the fluid film and bush. One-dimensional heat conduction equation is used for finding temperature in axial direction for journal. There is a very small effect of groove angle on film thickness, eccentricity ratio and pressure. There is a drastic change in attitude angle and side flow. Result shows that there is maximum power loss at large groove angle. So the smaller groove angle is recommended for two-axial groove journal bearing.

Design/methodology/approach

The finite element method is used for solving Reynolds equation for pressure distribution in fluid. The finite difference method is adopted for finding temperature distribution in bush, fluid and journal.

Findings

Pressure distribution in fluid is found out. Temperature distribution in bush, fluid and journal is found out. There is a very small effect of groove angle on film thickness, eccentricity ratio and pressure.

Research limitations/implications

The groove angle used is from 10 to 40 degree. The power loss is more when angle of groove increases, so smaller groove angle is recommended for this study.

Practical implications

The location of groove angle predicts the distribution of pressure and temperature in journal bearing. It will show the performance characteristics. ±90° angle we will prefer that will get before manufacturing of bearing.

Social implications

Due to this study, we will get predict how the pressure and temperature distribute in the journal. It will give the running condition of bearing as to at what speed and load we will get the maximum temperature and pressure in the bearing.

Originality/value

The finite element method is used for solving the Reynolds equation. Three-dimensional energy equation is solved using the finite difference method. Heat conduction equation is also solved for journal. The C language is used. The code is developed in C language. There are different equations which depend on each other. The temperature is dependent on pressure viscosity of fluid, etc. so C code is preferred.

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