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Article
Publication date: 1 August 2003

BEM/FVM conjugate heat transfer analysis of a three‐dimensional film cooled turbine blade

A. Kassab, E. Divo, J. Heidmann, E. Steinthorsson and F. Rodriguez

We report on the progress in the development and application of a coupled boundary element/finite volume method temperature‐forward/flux‐back algorithm developed to solve…

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Abstract

We report on the progress in the development and application of a coupled boundary element/finite volume method temperature‐forward/flux‐back algorithm developed to solve conjugate heat transfer arising in 3D film‐cooled turbine blades. We adopt a loosely coupled strategy where each set of field equations is solved to provide boundary conditions for the other. Iteration is carried out until interfacial continuity of temperature and heat flux is enforced. The NASA‐Glenn explicit finite volume Navier‐Stokes code Glenn‐HT is coupled to a 3D BEM steady‐state heat conduction solver. Results from a CHT simulation of a 3D film‐cooled blade section are compared with those obtained from the standard two temperature model, revealing that a significant difference in the level and distribution of metal temperatures is found between the two. Finally, current developments of an iterative strategy accommodating large numbers of unknowns by a domain decomposition approach is presented. An iterative scheme is developed along with a physically‐based initial guess and a coarse grid solution to provide a good starting point for the iteration. Results from a 3D simulation show the process that converges efficiently and offers substantial computational and storage savings.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 13 no. 5
Type: Research Article
DOI: https://doi.org/10.1108/09615530310482463
ISSN: 0961-5539

Keywords

  • Heat transfer
  • Coupled phenomena
  • Boundary elements
  • Finite volume

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Article
Publication date: 3 April 2017

Flow and heat transfer of couple stress fluid in a vertical channel in the presence of heat source/sink

Jawali Umavathi, Jada Prathap Kumar, Ioan Pop and Murudappa Shekar

The purpose of this paper is to consider the problem of fully developed laminar mixed convection flow of a couple stress fluid in a vertical channel with the third-kind…

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Abstract

Purpose

The purpose of this paper is to consider the problem of fully developed laminar mixed convection flow of a couple stress fluid in a vertical channel with the third-kind boundary conditions in the presence or absence of heat source/sink effect.

Design/methodology/approach

Through proper choice of dimensionless variables, the governing equations are developed. These governing equations are solved analytically by the differential transform method and numerically by the Runge–Kutta shooting method. Analytical solutions for the velocity and temperature profiles for heat generation and absorption of the problem are reported.

Findings

The mass flow rate and Nusselt numbers at both the left and right channel walls on mixed convection parameter, Brinkman number, couple stress parameter and heat generation/absorption parameter for equal and unequal Biot numbers are presented. Favorable comparisons of special cases with previously published work are obtained. It is found that velocity, temperature, mass flow rate and Nusselt number decrease with couple stress parameter and increase with mixed convection parameter and Brinkman number.

Originality/value

The work done in this paper is not done earlier to the authors’ knowledge. This is the first paper in which the sixth-order differential equation is solved using the semi-numerical method, which is a differential method.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 27 no. 4
Type: Research Article
DOI: https://doi.org/10.1108/HFF-12-2015-0540
ISSN: 0961-5539

Keywords

  • Mixed convection
  • Viscous dissipation
  • Couple stress fluid
  • Differential transform method
  • Heat source/sink
  • Third kind boundary conditions

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Article
Publication date: 7 January 2019

Numerical investigation of laminar forced convection for a non-Newtonian nanofluids flowing inside an elliptical duct under convective boundary condition

Haroun Ragueb and Kacem Mansouri

The purpose of this study is to investigate the thermal response of the laminar non-Newtonian fluid flow in elliptical duct subjected to a third-kind boundary condition…

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Abstract

Purpose

The purpose of this study is to investigate the thermal response of the laminar non-Newtonian fluid flow in elliptical duct subjected to a third-kind boundary condition with a particular interest to a non-Newtonian nanofluid case. The effects of Biot number, aspect ratio and fluid flow behavior index on the heat transfer have been examined carefully.

Design/methodology/approach

First, the mathematical problem has been formulated in dimensionless form, and then the curvilinear elliptical coordinates transform is applied to transform the original elliptical shape of the duct to an equivalent rectangular numerical domain. This transformation has been adopted to overcome the inherent mathematical deficiency due to the dependence of the ellipsis contour on the variables x and y. The yielded problem has been successfully solved using the dynamic alternating direction implicit method. With the available temperature field, several parameters have been computed for the analysis purpose such as bulk temperature, Nusselt number and heat transfer coefficient.

Findings

The results showed that the use of elliptical duct enhances significantly the heat transfer coefficient and reduces the duct’s length needed to achieve the thermal equilibrium. For some cases, the reduction in the duct’s length can reach almost 50 per cent compared to the circular pipe. In addition, the analysis of the non-Newtonian nanofluid case showed that the addition of nanoparticles to the base fluid improves the heat transfer coefficient up to 25 per cent. The combination of using an elliptical duct and the addition of nanoparticles has a spectacular effect on the overall heat transfer coefficient with an enhancement of 50-70 per cent. From the engineering applications view, the results demonstrate the potential of elliptical duct in building light-weighted compact shell-and-tube heat exchangers.

Originality/value

A complete investigation of the heat transfer of a fully developed laminar flow of power law fluids in elliptical ducts subject to the convective boundary condition with application to non-Newtonian nanofluids is addressed.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 1
Type: Research Article
DOI: https://doi.org/10.1108/HFF-02-2018-0055
ISSN: 0961-5539

Keywords

  • Convective boundary condition
  • Al2O3-methanol
  • Elliptical duct
  • MWCNTs-water
  • Non-Newtonian nanofluids
  • Power law fluid

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Article
Publication date: 1 May 2000

Heat removal of in‐tube viscous flows to air with the assistance of arrays of plate fins Part I: theoretical aspects involving 3‐D, 2‐D and 1‐D models

Antonio Campo

A detailed comparative study of the heat transfer augmentation of in‐tube flows accounting for an array of equally‐spaced plate fins attached at the outer surface is…

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Abstract

A detailed comparative study of the heat transfer augmentation of in‐tube flows accounting for an array of equally‐spaced plate fins attached at the outer surface is undertaken. The aim of the paper is to critically examine the thermal response of this kind of finned tubes to three different mathematical models: a complete 3‐D distributed model, a reduced 2‐D distributed/lumped hybrid model and two largely simplified 1‐D lumped models. For the three models tested, the computed results consistently demonstrate that the simplest 1‐D lumped model, with embedded arithmetic spatial‐ and geometric spatial‐means of the angular external convective coefficients provide dependable algebraic estimates of the actual heat transfer provided by the 3‐D distributed model with its indispensable finite‐difference solution. Further, an arithmetic mean of the maximum and minimum heat transfer supplied by the 1‐D lumped model delivered results that match those computed with the 3‐D distributed model. The most important steps of the mathematical derivations have been highlighted. A representative group of thermal performance diagrams is explained with the intent to assist engineers engaged in the thermal design of externally finned tubes of compact heat exchangers and HVAC devices.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 10 no. 3
Type: Research Article
DOI: https://doi.org/10.1108/09615530010318035
ISSN: 0961-5539

Keywords

  • Fins
  • Heat transfer
  • Flow

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Article
Publication date: 1 July 1995

A simultaneous iteration procedure for the finite element solution of the enthalpy model for phase change heat conduction problems

Zhen‐Xiang Gong and Arun S. Mujumdar

Based on a lumped mass model and an incremental iteration method, anefficient simultaneous iteration procedure is developed for the finiteelement solution of the enthalpy…

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Abstract

Based on a lumped mass model and an incremental iteration method, an efficient simultaneous iteration procedure is developed for the finite element solution of the enthalpy model. This procedure uses Gauss elimination to solve the resulting algebraic equation system. A one‐point quadrature program based on the isoparametric quadrilateral element is incorporated for the calculation of the heat conductance matrix, leading to a significant reduction of the computation time.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 5 no. 7
Type: Research Article
DOI: https://doi.org/10.1108/EUM0000000004078
ISSN: 0961-5539

Keywords

  • Finite element
  • Enthalpy
  • One point quadrature

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Article
Publication date: 6 March 2017

State estimation in bioheat transfer: a comparison of particle filter algorithms

Bernard Lamien, Leonardo A.B. Varon, Helcio R.B. Orlande and Guillermo E. Elicabe

The purpose of this paper is to focus on applications related to the hyperthermia treatment of cancer, with heating imposed either by a laser in the near-infrared range or…

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Abstract

Purpose

The purpose of this paper is to focus on applications related to the hyperthermia treatment of cancer, with heating imposed either by a laser in the near-infrared range or by radiofrequency waves. The particle filter algorithms are compared in terms of computational time and solution accuracy.

Design/methodology/approach

The authors extend the analyses performed in their previous works to compare three different algorithms of the particle filter, as applied to the hyperthermia treatment of cancer. The particle filters examined here are the sampling importance resampling (SIR) algorithm, the auxiliary sampling importance resampling (ASIR) algorithm and Liu & West’s algorithm.

Findings

Liu & West’s algorithm resulted in the largest computational times. On the other hand, this filter was shown to be capable of dealing with very large uncertainties. In fact, besides the uncertainties in the model parameters, Gaussian noises, similar to those used for the SIR and ASIR filters, were added to the evolution models for the application of Liu & West’s filter. For the three filters, the estimated temperatures were in excellent agreement with the exact ones.

Practical implications

This work may help medical doctors in the future to prescribe treatment protocols and also opens the possibility of devising control strategies for the hyperthermia treatment of cancer.

Originality/value

The natural solution to couple the uncertain results from numerical simulations with the measurements that contain uncertainties, aiming at the better prediction of the temperature field of the tissues inside the body, is to formulate the problem in terms of state estimation, as performed in this work.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 27 no. 3
Type: Research Article
DOI: https://doi.org/10.1108/HFF-03-2016-0118
ISSN: 0961-5539

Keywords

  • Laser heating
  • Inverse problems
  • Cancer
  • Hyperthermia
  • Particle filters
  • Radio-frequency heating

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Article
Publication date: 1 April 2003

MNEs, globalisation and digital economy: legal and economic aspects

Georgios I. Zekos

Aim of the present monograph is the economic analysis of the role of MNEs regarding globalisation and digital economy and in parallel there is a reference and examination…

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Abstract

Aim of the present monograph is the economic analysis of the role of MNEs regarding globalisation and digital economy and in parallel there is a reference and examination of some legal aspects concerning MNEs, cyberspace and e‐commerce as the means of expression of the digital economy. The whole effort of the author is focused on the examination of various aspects of MNEs and their impact upon globalisation and vice versa and how and if we are moving towards a global digital economy.

Details

Managerial Law, vol. 45 no. 1/2
Type: Research Article
DOI: https://doi.org/10.1108/03090550310770875
ISSN: 0309-0558

Keywords

  • Globalization
  • Digital marketing
  • Electronic commerce

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Article
Publication date: 1 June 2000

Field methods and computational techniques

A. Savini

Gives introductory remarks about chapter 1 of this group of 31 papers, from ISEF 1999 Proceedings, in the methodologies for field analysis, in the electromagnetic…

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Abstract

Gives introductory remarks about chapter 1 of this group of 31 papers, from ISEF 1999 Proceedings, in the methodologies for field analysis, in the electromagnetic community. Observes that computer package implementation theory contributes to clarification. Discusses the areas covered by some of the papers ‐ such as artificial intelligence using fuzzy logic. Includes applications such as permanent magnets and looks at eddy current problems. States the finite element method is currently the most popular method used for field computation. Closes by pointing out the amalgam of topics.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 19 no. 2
Type: Research Article
DOI: https://doi.org/10.1108/EUM0000000005355
ISSN: 0332-1649

Keywords

  • Electromagnetic fields
  • Electrical engineering
  • Electronics industry
  • Fuzzy logic
  • Computer technology

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Article
Publication date: 1 January 1983

Democratic Enterprise: A Policy Proposal for the Labour Movement

R.G.B. Fyffe

This book is a policy proposal aimed at the democratic left. It is concerned with gradual but radical reform of the socio‐economic system. An integrated policy of…

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Abstract

This book is a policy proposal aimed at the democratic left. It is concerned with gradual but radical reform of the socio‐economic system. An integrated policy of industrial and economic democracy, which centres around the establishment of a new sector of employee‐controlled enterprises, is presented. The proposal would retain the mix‐ed economy, but transform it into a much better “mixture”, with increased employee‐power in all sectors. While there is much of enduring value in our liberal western way of life, gross inequalities of wealth and power persist in our society.

Details

International Journal of Sociology and Social Policy, vol. 3 no. 1/2
Type: Research Article
DOI: https://doi.org/10.1108/eb012945
ISSN: 0144-333X

Keywords

  • Employees
  • Trade unions
  • Labour parties
  • Employee ownership
  • Distribution of wealth
  • Democracy
  • Industrial democracy
  • Social change
  • Social policy

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Article
Publication date: 1 January 1975

Managerial Law

Knight's Industrial Law Reports goes into a new style and format as Managerial Law This issue of KILR is restyled Managerial Law and it now appears on a continuous…

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Abstract

Knight's Industrial Law Reports goes into a new style and format as Managerial Law This issue of KILR is restyled Managerial Law and it now appears on a continuous updating basis rather than as a monthly routine affair.

Details

Managerial Law, vol. 18 no. 1
Type: Research Article
DOI: https://doi.org/10.1108/eb022383
ISSN: 0309-0558

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