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Article
Publication date: 1 October 2005

B.J. Henz, K.K. Tamma, R.V. Mohan and N.D. Ngo

The purpose of the present paper is to describe the modeling, analysis and simulations for the resin transfer molding (RTM), manufacturing process with particular emphasis…

Abstract

Purpose

The purpose of the present paper is to describe the modeling, analysis and simulations for the resin transfer molding (RTM), manufacturing process with particular emphasis on the sensitivity analysis for non‐isothermal applications.

Design/methodology/approach

For the manufacturing of advanced composites via RTM, besides the tracking of the resin flow fronts through a porous fiber perform, the heat transfer and the resin cure kinetics play an important role. The computational modeling is coupled multi‐disciplinary problem of flow‐thermal‐cure. The paper describes the so‐called continuous sensitivity formulation via the finite element method for this multi‐disciplinary problem for process modeling of composites manufactured by RTM to predict, analyze and optimize the manufacturing process.

Findings

Illustrative numerical examples are presented for two sample problems which include examination of sensitivity parameters for the case of material and geometric properties, and boundary conditions including fill time sensitivity analysis. The results indicate that the proposed formulations serve a useful role for the design and optimization of the RTM manufacturing process, thereby, avoiding heuristic trial‐and‐error methods.

Research limitations/implications

The paper restricts attention to constant properties and extensions to non‐linear thermophysical properties will serve as an added benefit.

Practical implications

The present efforts significantly impact the design/optimization process in the process modeling of composites manufactured by RTM.

Originality/value

To the authors' knowledge, this is the first time that continuous sensitivity analysis is done for non‐isothermal considerations in RTM.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 15 no. 7
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 12 April 2013

Chunlei Ruan, Jie Ouyang and Hongping Zhang

The purpose of this paper is to examine the macroscopic and microscopic fields of fiber suspensions in the non‐isothermal situations, also to examine the effect of fiber…

Abstract

Purpose

The purpose of this paper is to examine the macroscopic and microscopic fields of fiber suspensions in the non‐isothermal situations, also to examine the effect of fiber on this non‐isothermal system.

Design/methodology/approach

Control equations are coupled and simultaneously solved by collocated finite volume method on fully triangular meshes.

Findings

Temperature dependence and wall temperature have significant effect on both macroscopic and microscopic fields of fiber suspensions. Moreover, the influence of fiber on the non‐isothermal system is similar to that of the isothermal system.

Originality/value

This is the first time that the microstructures of both molecules and fibers are presented in the non‐isothermal condition and it is hoped that the results will provide more insight into the microscopics of complex flows.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 23 no. 3
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 8 June 2015

Soheila Shabaniverki and Siamak Serajzadeh

– The purpose of this paper is to study the kinetics of static recovery in cold-rolled aluminum alloy under different heating rates.

Abstract

Purpose

The purpose of this paper is to study the kinetics of static recovery in cold-rolled aluminum alloy under different heating rates.

Design/methodology/approach

Deformation modeling was first performed to assess the distributions of plastic strain and stress within the deformed alloy. In the next stage, thermal analysis and the rate equation of static recovery were employed to determine the progress of static recovery under non-isothermal conditions. Accordingly, a thermal finite element analysis and the Runge-Kutta method were utilized to handle the transient heat conduction and the progress of static recovery. Finally, low temperature annealing heat treatments were conducted to verify the model predictions. Accordingly, the tensile tests were conducted to measure the yield stresses of cold-rolled plates subjected to the subsequent annealing treatment at different temperatures and durations.

Findings

The results indicate that the employed algorithm can be used as an appropriate predictive tool for designing a low temperature heat treatment schedule to achieve the desired yield stress.

Originality/value

The kinetics of non-isothermal recovery and resulting yield stress are well predicted under practical annealing conditions.

Details

Multidiscipline Modeling in Materials and Structures, vol. 11 no. 1
Type: Research Article
ISSN: 1573-6105

Keywords

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Article
Publication date: 3 July 2017

Ming Xia

The main purpose of this paper is to present a comprehensive upscale theory of the thermo-mechanical coupling particle simulation for three-dimensional (3D) large-scale…

Abstract

Purpose

The main purpose of this paper is to present a comprehensive upscale theory of the thermo-mechanical coupling particle simulation for three-dimensional (3D) large-scale non-isothermal problems, so that a small 3D length-scale particle model can exactly reproduce the same mechanical and thermal results with that of a large 3D length-scale one.

Design/methodology/approach

The objective is achieved by following the scaling methodology proposed by Feng and Owen (2014).

Findings

After four basic physical quantities and their similarity-ratios are chosen, the derived quantities and its similarity-ratios can be derived from its dimensions. As the proposed comprehensive 3D upscale theory contains five similarity criteria, it reveals the intrinsic relationship between the particle-simulation solution obtained from a small 3D length-scale (e.g. a laboratory length-scale) model and that obtained from a large 3D length-scale (e.g. a geological length-scale) one. The scale invariance of the 3D interaction law in the thermo-mechanical coupled particle model is examined. The proposed 3D upscale theory is tested through two typical examples. Finally, a practical application example of 3D transient heat flow in a solid with constant heat flux is given to illustrate the performance of the proposed 3D upscale theory in the thermo-mechanical coupling particle simulation of 3D large-scale non-isothermal problems. Both the benchmark tests and application example are provided to demonstrate the correctness and usefulness of the proposed 3D upscale theory for simulating 3D non-isothermal problems using the particle simulation method.

Originality/value

The paper provides some important theoretical guidance to modeling 3D large-scale non-isothermal problems at both the engineering length-scale (i.e. the meter-scale) and the geological length-scale (i.e. the kilometer-scale) using the particle simulation method directly.

Details

Engineering Computations, vol. 34 no. 5
Type: Research Article
ISSN: 0264-4401

Keywords

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Article
Publication date: 2 January 2018

V.V. Ravikumar and S. Kumaran

The purpose of this paper is to study the corrosion behaviour of Al-12Zn-3Mg-2.5Cu alloy by cast, precipitation hardening and non-isothermal step rolling cum cold/cryo…

Abstract

Purpose

The purpose of this paper is to study the corrosion behaviour of Al-12Zn-3Mg-2.5Cu alloy by cast, precipitation hardening and non-isothermal step rolling cum cold/cryo rolling (−80 and −196°C) in 3.5 per cent NaCl solution.

Design/methodology/approach

Aluminium alloy with high alloying concentration (Zn: 12 per cent, Mg: 3 per cent, Cu: 2.5 per cent) was prepared by squeeze casting method with controlled process parameters. The cast alloy was solution treated at 450°C for 24 h and aged at 120°C with varying time intervals. Initially, the alloy also underwent non-isothermal step rolling from 6 mm to 3 mm at 400-100°C at the step of 100ºC with 15% reduction in thickness. Non-isothermal rolled alloy (3 mm thickness) was the starting material for further rolling at three different temperatures, such as room temperature, −80 and −190°C with 85 per cent reduction. Microstructural evolution during precipitation and thermo-mechanical processing was studied with the help of optical microscopy and electron microscopy. A potentio-dynamic polarization study was performed to evaluate the corrosion behaviour of Al-12Zn-3Mg-2.5Cu alloy processed in different conditions in 3.5 per cent NaCl solution.

Findings

There is a distinct evidence that the alloy exhibits varying corrosion resistance by changing its structural features. In fact, the alloy with ultra-fine grained structure exhibits good corrosion resistance than that of alloy in cast. This is attributed to a greater grain boundary region with high dislocation density, and plastic strain adversely affects the corrosion resistance.

Originality/value

The results obtained by this investigation help in understanding the effect of precipitation hardening and non-isothermal step rolling cum cold/cryo rolling (−80 and −196°C) on corrosion behaviour.

Details

Anti-Corrosion Methods and Materials, vol. 65 no. 1
Type: Research Article
ISSN: 0003-5599

Keywords

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Article
Publication date: 5 October 2015

Ming Xia

The purpose of this paper is to present an upscale theory of the thermal-mechanical coupling particle simulation for non-isothermal problems in two-dimensional…

Abstract

Purpose

The purpose of this paper is to present an upscale theory of the thermal-mechanical coupling particle simulation for non-isothermal problems in two-dimensional quasi-static system, under which a small length-scale particle model can exactly reproduce the same mechanical and thermal results with that of a large length-scale one.

Design/methodology/approach

The objective is achieved by extending the upscale theory of particle simulation for two-dimensional quasi-static problems from an isothermal system to a non-isothermal one.

Findings

Five similarity criteria, namely geometric, material (mechanical and thermal) properties, gravity acceleration, (mechanical and thermal) time steps, thermal initial and boundary conditions (Dirichlet/Neumann boundary conditions), under which a small-length-scale particle model can exactly reproduce both the mechanical and thermal behavior with that of a large length-scale model for non-isothermal problems in a two-dimensional quasi-static system are proposed. Furthermore, to test the proposed upscale theory, two typical examples subjected to different thermal boundary conditions are simulated using two particle models of different length scale.

Originality/value

The paper provides some important theoretical guidances to modeling thermal-mechanical coupled problems at both the engineering length scale (i.e. the meter scale) and the geological length scale (i.e. the kilometer scale) using the particle simulation method directly. The related simulation results from two typical examples of significantly different length scales (i.e. a meter scale and a kilometer scale) have demonstrated the usefulness and correctness of the proposed upscale theory for simulating non-isothermal problems in two-dimensional quasi-static system.

Details

Engineering Computations, vol. 32 no. 7
Type: Research Article
ISSN: 0264-4401

Keywords

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Article
Publication date: 1 December 2002

Anthony Wachs, Jean‐Robert Clermont and Ahmad Khalifeh

A finite volume method is applied to numerical simulations of steady isothermal and non‐isothermal flows of fluids obeying different constitutive equations: Newtonian…

Abstract

A finite volume method is applied to numerical simulations of steady isothermal and non‐isothermal flows of fluids obeying different constitutive equations: Newtonian, purely viscous with shear‐thinning properties (Carreau law) and viscoelastic Upper Convected Maxwell differential model whose temperature dependence is described by a William‐Landel‐Ferry equation. The flow situations concern various abrupt axisymmetric contractions from 2:1 to 16:1. Such flow geometries are involved in polymer processing operations. The governing equations are discretized on a staggered grid with an upwind scheme for the convective‐type terms and are solved by a decoupled algorithm, stabilized by a pseudo‐transient stress term and an elastic viscous stress splitting technique. The numerical results highlight the influence of temperature on the flow situations, and also the complex behaviour of the materials under non‐isothermal conditions.

Details

Engineering Computations, vol. 19 no. 8
Type: Research Article
ISSN: 0264-4401

Keywords

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Article
Publication date: 4 January 2021

Varinder Kumar and Santosh Bopche

This paper aims to present the numerical models and experimental outcomes pertain to the performance of the parabolic dish concentrator system with a modified cavity-type…

Abstract

Purpose

This paper aims to present the numerical models and experimental outcomes pertain to the performance of the parabolic dish concentrator system with a modified cavity-type receiver (hemispherical-shaped).

Design/methodology/approach

The numerical models were evolved based on two types of boundary conditions; isothermal receiver surface and non-isothermal receiver surface. For validation of the numerical models with experimental results, three statistical terms were used: mean of absolute deviation, R2 and root mean square error.

Findings

The thermal efficiency of the receiver values obtained using the numerical model with a non-isothermal receiver surface found agreeing well with experimental results. The numerical model with non-isothermal surface boundary condition exhibited more accurate results as compared to that with isothermal surface boundary condition. The receiver heat loss analysis based on the experimental outcomes is also carried out to estimate the contributions of various modes of heat transfer. The losses by radiation, convection and conduction contribute about 27.47%, 70.89% and 1.83%, in the total receiver loss, respectively.

Practical implications

An empirical correlation based on experimental data is also presented to anticipate the effect of studied parameters on the receiver collection efficiency. The anticipations may help to adopt the technology for practical use.

Social implications

The developed models would help to design and anticipating the performance of the dish concentrator system with a modified cavity receiver that may be used for applications e.g. power generation, water heating, air-conditioning, solar cooking, solar drying, energy storage, etc.

Originality/value

The originality of this manuscript comprising presenting a differential-mathematical analysis/modeling of hemispherical shaped modified cavity receiver with non-uniform surface temperature boundary condition. It can estimate the variation of temperature of heat transfer fluid (water) along with the receiver height, by taking into account the receiver cavity losses by means of radiation and convection modes. The model also considers the radiative heat exchange among the internal ring-surface elements of the cavity.

Details

World Journal of Engineering, vol. 18 no. 2
Type: Research Article
ISSN: 1708-5284

Keywords

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Article
Publication date: 2 November 2015

Adel Chine, Amine Ammar and J.R. Clermont

The purpose of this paper is to compute flow effects of the transition from adherence-to-slip in two-dimensional flows, for a polymer melt obeying a memory-integral…

Abstract

Purpose

The purpose of this paper is to compute flow effects of the transition from adherence-to-slip in two-dimensional flows, for a polymer melt obeying a memory-integral viscoelastic equation, in isothermal and non-isothermal cases.

Design/methodology/approach

Temperature dependence is expressed by Arrhenius and William-Landel-Ferry models. A coupling approach is defined. For the dynamic equations, the Stream-Tube Method (STM) is used with finite differences in a mapped rectangular domain of the real domain, where streamlines are parallel and straight. STM avoids particle-tracking problems and allows simple formulae to evaluate stresses resulting from the constitutive equation. For the temperature field, a finite-element method is carried out to solve the energy equation in the real domain.

Findings

The approach avoids numerical problems arising with classical formulations and proves to be robust and efficient. Large elasticity levels are attained without convergence and refinement difficulties that may arise close to the “stick-slip” transition section. The method highlights the role of temperature conditions and reveals interesting differences for the ducts considered.

Practical implications

The results of the study are of interest for polymer processing where slip at the wall can be encountered, in relation with the physical properties of the materials.

Originality/value

The paper presents a simple approach that limits considerably numerical problems coming from stick-slip boundary conditions and avoids particle-tracking. Results are obtained at flow rates encountered in industrial conditions.

Details

Engineering Computations, vol. 32 no. 8
Type: Research Article
ISSN: 0264-4401

Keywords

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Article
Publication date: 29 April 2014

Marek Jaszczur

The purpose of this paper is to numerically study heated channel flow using direct numerical simulation (DNS) and large eddy simulation (LES) method. Using different…

Abstract

Purpose

The purpose of this paper is to numerically study heated channel flow using direct numerical simulation (DNS) and large eddy simulation (LES) method. Using different domain size and different grid resolution it is show that filtering procedure is influenced and may results in very different solutions.

Design/methodology/approach

Turbulent non-isothermal fully developed channel flow has been investigated using LES. The filtered Navier-stokes and energy equations were numerically solved with dynamic subgrid scale (SGS) model, standard Smagorinsky model or without additional model for the turbulent SGS stress and heat flux required to close the governing equations.

Findings

The numerical LES results in comparison with the DNS data demonstrate that the LES computations may not always offers a reliable prediction of non-isothermal turbulent flow in open channel. It has been found that, even though the models reproduces accurately results for the flow field the thermal field computed using LES do not necessary match the DNS results. Introducing SGS model for scalar do not always show large improvement. One of the reason is thickness of hydrodynamic and thermal boundary layer. In the cases when boundary layers are very different it is not easy optimally set up control volumes in the domain.

Originality/value

This is one of the first instance in which a results of numerical computations for different grid resolution, different stretching, SGS model is employed for non-isothermal turbulent channel flow. It shows that in the cases when boundary layers hydrodynamic and thermal are very different it is hardly find optimal grid resolution or stretching

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 24 no. 4
Type: Research Article
ISSN: 0961-5539

Keywords

1 – 10 of 365