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Article
Publication date: 22 November 2018

Mohamed Issam Elkhazen, Walid Hassen, Hakan F. Öztop, Lioua Kolsi, Abdullah A.A.A. Al-Rashed, Mohamed Naceur Borjini and Mohamed E. Ali

The purpose of this work is to highlight the effects of partial unipolar injection on electro-thermo-convection (ETC) in dielectric liquid contained between two eccentric…

Abstract

Purpose

The purpose of this work is to highlight the effects of partial unipolar injection on electro-thermo-convection (ETC) in dielectric liquid contained between two eccentric cylinders.

Design/methodology/approach

A finite volume method was used to solve governing equations. The study is performed for different parameters, such as radius ratio (0.2 ≤ Γ ≤ 0.6), dimensionless electric Rayleigh number (0 ≤ T ≤ 900), eccentricity (−0.4 ≤ e ≤ 0.4) and thermal Rayleigh number (10 ≤ Ra ≤ 5.105).

Findings

It is found that heat transfer increases with increase in dimensionless electric Rayleigh number and eccentricity ratio.

Originality/value

The originality of this work is to analyze the ETC in dielectric liquid subjected to partial unipolar injection between two eccentric cylinders

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 1
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 26 October 2018

Abdullah A.A.A. Al-Rashed, Lioua Kolsi, Mohammed A. Tashkandi, Emad Hasani Malekshah, Ali J. Chamkha and Mohamad Naceur Borjini

The purpose of this paper is to investigate the coupled effect of magnetic field and radiation on convective heat transfer of low electrically conductive dielectric oxide melt.

Abstract

Purpose

The purpose of this paper is to investigate the coupled effect of magnetic field and radiation on convective heat transfer of low electrically conductive dielectric oxide melt.

Design/methodology/approach

The 3D Navier–Stokes equations are formulated using the vector potential-vorticity formulation and solved using the finite volume method (FVM). The radiative heat transfer equation is discretized using the FTnFVM method. A code was written using FORTRAN language.

Findings

The obtained numerical results are focused on the effect of the different parameters on the heat transfer and the flow structure with a special interest on the 3D transvers flow. It is found that the flow is developing in inner spirals and the magnetic field intensifies this 3D character. The radiation acts mainly at the core of the enclosure and causes the apparition of the merging phenomenon near the front and back walls.

Originality/value

The effect of magnetic field on convective heat transfer of highly electrically conductive fluids has been intensively studied. Reciprocally, the case of a fluid with low electrical conductivity is not so much investigated, especially when it is coupled with the effect of radiation. These two effects are studied in this paper for the case of a low-conductive LiNbO3 oxide melt.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 10
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 6 November 2017

Irfan Anjum Badruddin, Azeem Khan, Mohd Yamani Idna Idris, N. Nik-Ghaali, Salman Ahmed N.J. and Abdullah A.A.A. Al-Rashed

The purpose of this paper is to highlight the advantages of a simplified algorithm to solve the problem of heat and mass transfer in porous medium by reducing the number…

Abstract

Purpose

The purpose of this paper is to highlight the advantages of a simplified algorithm to solve the problem of heat and mass transfer in porous medium by reducing the number of partial differential equations from four to three.

Design/methodology/approach

The approach of the present paper is to develop a simplified algorithm to reduce the number of equations involved in conjugate heat transfer in porous medium.

Findings

Developed algorithm/method has many advantages over conventional method of solution for conjugate heat transfer in porous medium.

Research limitations/implications

The current work is applicable to conjugate heat transfer problem.

Practical implications

The developed algorithm is useful in reducing the number of equations to be solved, thus reducing the computational resources required.

Originality/value

Development of simplified algorithm and comparison with conventional method.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 27 no. 11
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 15 August 2019

Iman Rashidi, Lioua Kolsi, Goodarz Ahmadi, Omid Mahian, Somchai Wongwises and E. Abu-Nada

This study aims to investigate a three-dimensional computational modelling of free convection of Al2O3 water-based nanofluid in a cylindrical cavity under heterogeneous…

Abstract

Purpose

This study aims to investigate a three-dimensional computational modelling of free convection of Al2O3 water-based nanofluid in a cylindrical cavity under heterogeneous heat fluxes that can be used as a thermal storage tank.

Design/methodology/approach

Effects of different heat flux boundary conditions on heat transfer and entropy generation were examined and the optimal configuration was identified. The simulation results for nanoparticle (NP) volume fractions up to 4 per cent, and Rayleigh numbers of 104, 105 and 106 were presented.

Findings

The results showed that for low Ra (104) the heat transfer and entropy generation patterns were symmetric, whereas with increasing the Rayleigh number these patterns became asymmetric and more complex. Therefore, despite the symmetric boundary conditions imposed on the periphery of the enclosure (uniform in Ɵ), it was necessary to simulate the problem as three-dimensional instead of two-dimensional. The simulation results showed that by selecting the optimal values of heat flux distribution and NP volume fraction for these systems the energy consumption can be reduced, and consequently, the energy efficiency can be ameliorated.

Originality/value

The results of the present study can be used for the design of energy devices such as thermal storage tanks, as both first and second laws of thermodynamics have been considered. Using the optimal design will reduce energy consumption.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 30 no. 1
Type: Research Article
ISSN: 0961-5539

Keywords

Article
Publication date: 29 January 2021

Daryoush Kamali, Saeid Hejri, Narges Akbar and Emad Hasani Malekshah

The purpose of this study is to present a comprehensive hydrothermal analysis on an inclined mini-channel using numerical and experimental techniques. The fin array acts…

Abstract

Purpose

The purpose of this study is to present a comprehensive hydrothermal analysis on an inclined mini-channel using numerical and experimental techniques. The fin array acts as heat source within the channel, and a wavy wall located at the top of the channel is heat sink. The side walls are insulated with curved profiles. Also, the channel is inclined with four known inclination angles. To solve the governing equations, the dual-multi-relaxation-time lattice Boltzmann method with D2Q9 and D2Q5 lattice models for flow and temperature fields is used, respectively. Also, the channel is filled with SiO2-glycol nanofluid.

Design/methodology/approach

Identifying the behavior of a thermal component during natural convective flow is a challenging topic due to its complexities. This paper focuses on analyzing the thermal and hydrodynamic aspects of a narrow channel equipping with fin array.

Findings

Two correlations are proposed considering temperature and volume fraction ranges for thermal conductivity and dynamic viscosity according to measured experimental data which are used in the numerical phase. Finally, the structure of flow, temperature distribution of fluid, local thermal and viscous dissipations, volume-averaged entropy production, Bejan number and heat transfer rate are extracted by numerical simulations. The results show that the average Nusselt number enhances about 57% (maximum enhancement percentage) when volume fraction increases from 1% to 3% at Ra = 106 and θ = 90°. In addition, the value of entropy generation is maximum at φ = 1%, Ra = 106 and φ = 90°. Also, the maximum enhancement of entropy generation in range of Ra = 103 to 106 is about 4 times at φ = 1% and θ = 90°.

Originality/value

The originality of the present study is combining a modern numerical method (i.e. dual/multi-relaxation-time LBM) with experimental observation on characteristics of SiO2-glycol nanofluid to study the thermal and hydrodynamic properties of the studied mini-channel.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 31 no. 7
Type: Research Article
ISSN: 0961-5539

Keywords

Book part
Publication date: 20 May 2019

Murniati Mukhlisin and Leny Nofianti

Islamic financial institutions offer a different paradigm from conventional institutions. From corporate governance (CG) viewpoint, it embodies a number of interesting…

Abstract

Islamic financial institutions offer a different paradigm from conventional institutions. From corporate governance (CG) viewpoint, it embodies a number of interesting features since equity participation and profit-and-loss sharing arrangements form the basis of Islamic financing. These financial arrangements imply different stakeholder relationships and governance structures, and distinct from the conventional model since depositors have a direct financial stake in the bank's investment and equity participations. On top of that, the Islamic bank is subject to an additional layer of governance since the suitability of its investment and financing must be in strict conformity with Islamic law and the expectations of the Muslim community. Other form of governance such as accounting standards have also been an issue whether they have met the reporting requirement of Islamic financial institutions that carry title as “Islamic” as there is no uniformity. Therefore, there should be concerted efforts to revisit the existing good CG and accounting standards for Islamic financial institutions.

Details

Research in Corporate and Shari’ah Governance in the Muslim World: Theory and Practice
Type: Book
ISBN: 978-1-78973-007-4

Keywords

Article
Publication date: 20 October 2014

Mohammed Abdullah Al Rashed and Tariq Pervez Sattar

The purpose of this paper is to develop a wireless positioning system. The automation of non-destructive testing (NDT) of large and complex geometry structures such as…

Abstract

Purpose

The purpose of this paper is to develop a wireless positioning system. The automation of non-destructive testing (NDT) of large and complex geometry structures such as aircraft wings and fuselage is prohibitively expensive, though automation promises to improve on manual ultrasound testing. One inexpensive way to achieve automation is by using a small wall-climbing mobile robot to move a single ultrasound probe over the surface through a scanning trajectory defined by a qualified procedure. However, the problem is to guide the robot though the trajectory and know whether it has followed it accurately to confirm that the qualified procedure has been carried out.

Design/methodology/approach

The approach is to use sophisticated bulk electronics developed for game playing in combination with MATLAB to develop a wireless positioning system.

Findings

The paper describes the development of an inexpensive wireless system comprising an optical spatial positioning system and inertial measurement unit that relates the 3D location of an NDT probe carried by a mobile robot to a computer-aided drawing (CAD) representation of the test structure in a MATLAB environment. The probe is located to an accuracy of ± 2 mm at distances of 5 m.

Research limitations/implications

Positioning range is limited to 5 m. Further development is required to increase this range.

Practical implications

The wireless system is used to develop tools to guide the robot remotely to follow a desired scanning trajectory, obtain feedback about the actual trajectory executed by the robot, know exactly where an ultrasound pulse echo was captured, map identified defects on the CAD and relate them to the real test object.

Originality/value

An inexpensive spatial positioning system with sufficient accuracy for automated NDT purposes.

Details

Industrial Robot: An International Journal, vol. 41 no. 6
Type: Research Article
ISSN: 0143-991X

Keywords

Article
Publication date: 1 July 2021

Mirza Mohammad Didarul Alam, Rashed Al Karim and Wardha Habiba

The present study investigates the moderating role of customer trust in customer relationship management (CRM) components and customer loyalty relationships in the context…

1878

Abstract

Purpose

The present study investigates the moderating role of customer trust in customer relationship management (CRM) components and customer loyalty relationships in the context of the baking sector in Bangladesh.

Design/methodology/approach

Data were collected through a survey using a structured questionnaire from 350 customers of commercial banks in Bangladesh.

Findings

The key finding is that all CRM components (customer orientation, customer advocacy and customer knowledge) except customer engagement have positive impact on customer loyalty. Moreover, customer trust only moderates the relationship between customer knowledge and customer loyalty, whereas other CRM components and customer loyalty do not moderate by trust.

Originality/value

The findings of the study add to the substantial pool of knowledge on CRM components, customer trust and customer loyalty literature. More specifically, the moderating role of customer trust between customer knowledge and customer loyalty is the novel contribution of this research which will enrich the existing CRM literature particularly in the banking sector of Bangladesh.

Details

International Journal of Bank Marketing, vol. 39 no. 7
Type: Research Article
ISSN: 0265-2323

Keywords

Open Access
Article
Publication date: 23 May 2020

Aboubakr Fathy Awaad

This study aims to highlight the dimensions of the rivalry over the regional role between two regional powers in the Middle East, and the impact of local, regional and…

2388

Abstract

Purpose

This study aims to highlight the dimensions of the rivalry over the regional role between two regional powers in the Middle East, and the impact of local, regional and international pressures of the Syrian crisis on the role performance of the competing forces.

Design/methodology/approach

The study is based on using “the role approach” as an analytical frame to benefit by the application of the theory of role. This approach allows the possibility of linking various analytical levels, both in clarifying the relationship between internal and external factors and showing the interaction between elements of perception, abilities and behavior.

Findings

The international pressures shall remain governing the frame of competition among the roles of the regional powers, through determining the course of competition and its direct impact on its results.

Originality/value

This study examines the phenomenon of regional rivalry between two distinct and competing regional powers, in a turbulent environment in the wake of the Arab Spring crises, which created opportunities and challenges for regional powers, especially in Syria, where it intersected with the interests and policies of major and regional powers.

Details

Review of Economics and Political Science, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 2356-9980

Keywords

Article
Publication date: 19 December 2018

Ameer Ahamad Nandalur, Sarfaraz Kamangar and Irfan Anjum Badruddin

The purpose of this study was to analyze the heat transfer in a square porous cavity that has a solid block placed at its center. The prime focus of this study is to…

Abstract

Purpose

The purpose of this study was to analyze the heat transfer in a square porous cavity that has a solid block placed at its center. The prime focus of this study is to investigate the effect of size of the square solid block and other physical parameters on the heat transfer rate from the hot surface into the porous medium. The left vertical surface of cavity is maintained at a hot temperature and the right vertical surface at a cool temperature, Tc. The finite element method is used to simplify the governing equations and is solved iteratively. It is noted that the size of the solid block plays a vital role in dictating the heat transfer from the hot surface to porous medium.

Design/methodology/approach

The current work is based on finite element formulation of a square porous cavity that has a solid square block placed at its center. Governing equations were solved iteratively.

Findings

The size of the solid block has a pronounced effect on the heat transfer behavior inside the porous cavity.

Originality/value

This study highlights the heat transfer due to a conducting square solid block at mid of porous cavity.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 2
Type: Research Article
ISSN: 0961-5539

Keywords

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