Search results

1 – 10 of 117
To view the access options for this content please click here
Article
Publication date: 6 February 2017

Huey Tyng Cheong, S. Sivasankaran and M. Bhuvaneswari

The purpose of this paper is to study natural convective flow and heat transfer in a sinusoidally heated wavy porous cavity in the presence of internal heat generation or…

Abstract

Purpose

The purpose of this paper is to study natural convective flow and heat transfer in a sinusoidally heated wavy porous cavity in the presence of internal heat generation or absorption.

Design/methodology/approach

Sinusoidal heating is applied on the vertical left wall of the cavity, whereas the wavy right wall is cooled at a constant temperature. The top and bottom walls are taken to be adiabatic. The Darcy model is adopted for fluid flow through the porous medium in the cavity. The governing equations and boundary conditions are solved using the finite difference method over a range of amplitudes and number of undulations of the wavy wall, Darcy–Rayleigh numbers and internal heat generation/absorption parameters.

Findings

The results are presented in the form of streamlines, isotherms and Nusselt numbers for different values of right wall waviness, Darcy–Rayleigh number and internal heat generation parameter. The flow field and temperature distribution in the cavity are affected by the waviness of the right wall. The wavy nature of the cavity also enhances the heat transfer into the system. The heat transfer rate in the cavity decreases with an increase in the internal heat generation/absorption parameter.

Research limitations/implications

The present investigation is conducted for steady, two-dimensional natural convective flow in a wavy cavity filled with Darcy porous medium. The waviness of the right wall is described by the amplitude and number of undulations with a well-defined mathematical function. An extension of the present study with the effects of cavity inclination and aspect ratio will be the interest for future work.

Practical implications

The study might be useful for the design of solar collectors, room ventilation systems and electronic cooling systems.

Originality/value

This work examines the effects of sinusoidal heating on convective heat transfer in a wavy porous cavity in the presence of internal heat generation or absorption. The study might be useful for the design of solar collectors, room ventilation systems and electronic cooling systems.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 27 no. 2
Type: Research Article
ISSN: 0961-5539

Keywords

To view the access options for this content please click here
Article
Publication date: 3 April 2017

K. Janagi, S. Sivasankaran, M. Bhuvaneswari and M. Eswaramurthi

The aim of the present study is to analyze the natural convection flow and heat transfer of cold water around °C in a square porous cavity. The horizontal walls of cavity…

Abstract

Purpose

The aim of the present study is to analyze the natural convection flow and heat transfer of cold water around °C in a square porous cavity. The horizontal walls of cavity are adiabatic, and the vertical walls are maintained at different temperatures. The right side wall is maintained at temperature θc, and the left side wall is maintained at sinusoidal temperature distribution.

Design/methodology/approach

The Brinkman–Forchheimer-extended Darcy model for porous medium is used to study the effects of density inversion parameter, Rayleigh number and impact of Darcy number and porosity. The finite volume method is used to solve the governing equations.

Findings

The heat transfer rate is increased on increasing the Darcy number and porosity. Also, the convective heat transfer rate is decreased first and then increased on increasing the density inversion parameter.

Research limitations/implications

The numerical computations have been carried out for the Darcy number ranging of 10(−4)Da ≤ 10(−1), the porosity ranging of 0.4 ≤ ε ≤ 0.8 and the density inversion parameter ranging of 0 ≤ Tm ≤ 1 and keeping Ra = 106.

Practical implications

The results can be used in the cooling of electronic components, thermal storage system and in heat exchangers.

Originality/value

The choice of consideration of sinusoidal heating and density maximum effect produces good result in flow field and temperature distribution. The obtained results can be used in various fields.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 27 no. 4
Type: Research Article
ISSN: 0961-5539

Keywords

To view the access options for this content please click here
Article
Publication date: 2 October 2017

Ruhaila Md Kasmani, S. Sivasankaran, M. Bhuvaneswari and Ahmed Kadhim Hussein

The purpose of this study is to investigate the Soret and Dufour effects on the double-diffusive convective boundary layer flow of a nanofluid past a moving wedge in the…

Abstract

Purpose

The purpose of this study is to investigate the Soret and Dufour effects on the double-diffusive convective boundary layer flow of a nanofluid past a moving wedge in the presence of suction.

Design/methodology/approach

The similarity transformation is applied to convert the governing nonlinear partial differential equations into ordinary differential equations. Then, they are solved numerically by the fourth-order Runge–Kutta–Gill method along with the shooting technique and the Newton–Raphson method. In addition, the ordinary differential equations are also analytically solved by the homotopy analysis method.

Findings

The results for dimensionless velocity, temperature, solutal concentration and nanoparticle volume fraction profiles, as well as local skin friction coefficient and local Nusselt and local Sherwood numbers are presented through the plots for various combinations of pertinent parameters involved in the study. The heat transfer rate increases on increasing the Soret parameter and it decreases on increasing the Dufour parameter. The mass transfer behaves oppositely to heat transfer.

Practical implication

In engineering applications, a wedge is used to hold objects in place, such as engine parts in the gate valves. A gate valve is the valve that opens by lifting a wedge-shaped disc to control the timing and quantity of fluid flow into an engine.

Originality/value

No such investigation is available in literature, and therefore, the results obtained are novel.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 27 no. 10
Type: Research Article
ISSN: 0961-5539

Keywords

To view the access options for this content please click here
Article
Publication date: 7 February 2020

Ali S. Alshomrani, S. Sivasankaran and Amer Abdulfattah Ahmed

This study aims to deal the numerical simulation on buoyant convection and energy transport in an inclined cubic box with diverse locations of the heater and coolers.

Abstract

Purpose

This study aims to deal the numerical simulation on buoyant convection and energy transport in an inclined cubic box with diverse locations of the heater and coolers.

Design/methodology/approach

The left/right walls are cooled partially whereas the other walls are kept adiabatic. In the left/right walls, three different locations of the cooler are examined, whereas heater moves in three locations in the middle of the enclosed box. The governing models are numerically solved using the finite-element method.

Findings

The simulations are done on several values of the Rayleigh number and cavity inclination angles and different locations of the heater and coolers. The results are presented in the form of streamlines, isosurfaces and Nusselt numbers for different values of parameter involved here. It is recognized that the inclination of the box and the locations of the coolers strongly influence the stream and energy transport inside the enclosed domain.

Research limitations/implications

The present investigation is conducted for steady, laminar, three-dimensional natural convective flow in a box for different locations of cooler and tilting angles of a cavity. The study might be useful to the design of solar collectors, room ventilation systems and electronic cooling systems.

Originality/value

This work examines the effects of different locations of cooler and tilting angles of a cavity on convective heat transfer in a 3D cavity. The study is useful for thermal engineering applications.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 30 no. 10
Type: Research Article
ISSN: 0961-5539

Keywords

To view the access options for this content please click here
Article
Publication date: 7 June 2013

A. Malleswaran, S. Sivasankaran and M. Bhuvaneswari

The main objective of the present study is to investigate the effects of various lengths and different locations of the heater on the left sidewall in a square lid‐driven cavity.

Abstract

Purpose

The main objective of the present study is to investigate the effects of various lengths and different locations of the heater on the left sidewall in a square lid‐driven cavity.

Design/methodology/approach

The non‐dimensional equations are discretized by the finite‐volume method. The upwind scheme and the central difference scheme are implemented for the convection and the diffusion terms, respectively.

Findings

On increasing the Richardson number, the overall heat transfer is increased whether the length and the location of the heater is considered or not. Among the various lengths of the heater considered, the total heat transfer is better only for the length LH=1/3 of the heater if it is extended from top or bottom of the cavity. In the case of location of the heater, the average heat transfer enhances for center location of the heater. Existence of the magnetic field suppresses the convective heat transfer and the fluid flow.

Practical implications

The results can be used in the cooling of electronic devices and heat transfer improvement in heat exchangers.

Originality/value

The numerical results obtained here focus on the detailed investigation of flow and temperature field in a discretely heated lid‐driven square cavity. The findings will be helpful in many applications such as heat exchangers and cooling of electronic devices.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 23 no. 5
Type: Research Article
ISSN: 0961-5539

Keywords

To view the access options for this content please click here
Article
Publication date: 6 February 2017

S. Sivasankaran, H. Niranjan and M. Bhuvaneswari

The purpose of this paper is to investigate the Newtonian heating and slip effect on mixed convective flow near a stagnation point in a porous medium with thermal…

Abstract

Purpose

The purpose of this paper is to investigate the Newtonian heating and slip effect on mixed convective flow near a stagnation point in a porous medium with thermal radiation in the presence of magnetohydrodynamic (MHD), heat generation/absorption and chemical reaction.

Design/methodology/approach

The governing nonlinear coupled equations are converted into ordinary differential equations by similarity transformation. These equations are solved numerically using a Runge–Kutta–Fehlberg method with shooting technique and analytically using the homotopy analysis method (HAM).

Findings

The effects of different parameters on the fluid flow and heat transfer are investigated. It is found that the velocity and temperature profiles increase on an increase in the Biot number. The velocity and concentration profiles increase on decreasing the chemical reaction parameter.

Practical implications

This paper is helpful to the engineers and scientists in the field of thermal and manufacturing engineering.

Originality/value

The two-dimensional boundary layer flow over a vertical plate with slip and convective boundary conditions near the stagnation-point is analysed in the presence of magnetic field, radiation and heat generation/absorption. This paper is helpful to the engineers and scientists in the field of thermal and manufacturing engineering.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 27 no. 2
Type: Research Article
ISSN: 0961-5539

Keywords

To view the access options for this content please click here
Article
Publication date: 6 May 2021

Bo Xie and Yuan-Ming Wang

This paper aims to discuss the stagnation-point flow and heat transfer for power-law fluid pass through a stretching surface with heat generation effect. Unlike the…

Abstract

Purpose

This paper aims to discuss the stagnation-point flow and heat transfer for power-law fluid pass through a stretching surface with heat generation effect. Unlike the previous considerations about the research on stagnation-point flow, the process of heat transfer and the convective heat transfer boundary condition use the modified Fourier’s law in which the heat flux is power-law-dependent on velocity gradient.

Design/methodology/approach

The similarly transformation is used to convert the governing partial differential equations into a series of ordinary differential equations which are solved analytically by using the differential transform method and the base function method.

Findings

The variations of the velocity and temperature fields for different specific related parameters are graphically discussed and analyzed. There is a special phenomenon that all the velocity profiles converge from the initial value of velocity to stagnation parameter values. And the larger power-law index enhancesthe momentum diffusion. A significant phenomenon can be observed that the larger power-law index causes a decline in the heat flux. This influence indicates that the higher viscosity restricts the heat transfer. Furthermore, both velocity gradient and temperature gradient play an indispensable role in the processes of heat transfer.

Originality/value

This paper researches the process of heat transfer of stagnation-point flow ofpower-law magneto-hydro-dynamical fluid over a stretching surface with modified convective heat transfer boundary condition.

Details

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

Keywords

To view the access options for this content please click here
Article
Publication date: 25 September 2019

Iman Sedighi, Majid R. Ayatollahi, Bahador Bahrami, Marco A. Pérez-Martínez and Andres A. Garcia-Granada

The purpose of this paper is to investigate the effect of layer orientation on the tensile, flexural and fracture behavior of additively manufactured (AM) polycarbonate…

Abstract

Purpose

The purpose of this paper is to investigate the effect of layer orientation on the tensile, flexural and fracture behavior of additively manufactured (AM) polycarbonate (PC) produced using fused deposition modeling (FDM).

Design/methodology/approach

An experimental approach is undertaken and a total number of 48 tests are conducted. Two types of tensile specimens are used and their mechanical behavior and fracture surfaces are studied. Also, circular parts with different layer orientations are printed and two semi-circular bending (SCB) samples are extracted from each part. Finally, the results of samples with different build directions are compared to one another to better understand the mechanical behavior of additively manufactured PC.

Findings

The results demonstrate anisotropy in the tensile, flexural and fracture behavior of the additively manufactured PC parts with the latter being less anisotropic compared to the first two. It is also demonstrated that the anisotropy of the elastic modulus is small and can be neglected. Tensile strength ranges from 40 MPa to 53 MPa. At the end, mode I fracture toughness prediction curves are provided for different directions of the FDM samples. Fracture toughness ranges from 1.93 to 2.37 MPa.mm1/2.

Originality/value

The SCB specimen, a very suitable geometry for characterizing anisotropic materials, was used to characterize FDM parts for the first time. Also, the fracture properties of the AM PC have not been studied by the researchers in the past. Therefore, fracture toughness prediction curves are presented for this anisotropic material. These curves can be very suitable for designing parts that are going to be produced by 3D printing. Moreover, the effect of the area to perimeter ratio on the tensile properties of the printed parts is investigated.

Details

Rapid Prototyping Journal, vol. 26 no. 2
Type: Research Article
ISSN: 1355-2546

Keywords

To view the access options for this content please click here
Article
Publication date: 25 February 2021

Leo Lukose and Tanmay Basak

The purpose of this paper is to address various works on mixed convection and proposes 10 unified models (Models 1–10) based on various thermal and kinematic conditions of…

Abstract

Purpose

The purpose of this paper is to address various works on mixed convection and proposes 10 unified models (Models 1–10) based on various thermal and kinematic conditions of the boundary walls, thermal conditions and/ or kinematics of objects embedded in the cavities and kinematics of external flow field through the ventilation ports. Experimental works on mixed convection have also been addressed.

Design/methodology/approach

This review is based on 10 unified models on mixed convection within cavities. Models 1–5 involve mixed convection based on the movement of single or double walls subjected to various temperature boundary conditions. Model 6 elucidates mixed convection due to the movement of single or double walls of cavities containing discrete heaters at the stationary wall(s). Model 7A focuses mixed convection based on the movement of wall(s) for cavities containing stationary solid obstacles (hot or cold or adiabatic) whereas Model 7B elucidates mixed convection based on the rotation of solid cylinders (hot or conductive or adiabatic) within the cavities enclosed by stationary or moving wall(s). Model 8 is based on mixed convection due to the flow of air through ventilation ports of cavities (with or without adiabatic baffles) subjected to hot and adiabatic walls. Models 9 and 10 elucidate mixed convection due to flow of air through ventilation ports of cavities involving discrete heaters and/or solid obstacles (conductive or hot) at various locations within cavities.

Findings

Mixed convection plays an important role for various processes based on convection pattern and heat transfer rate. An important dimensionless number, Richardson number (Ri) identifies various convection regimes (forced, mixed and natural convection). Generalized models also depict the role of “aiding” and “opposing” flow and combination of both on mixed convection processes. Aiding flow (interaction of buoyancy and inertial forces in the same direction) may result in the augmentation of the heat transfer rate whereas opposing flow (interaction of buoyancy and inertial forces in the opposite directions) may result in decrease of the heat transfer rate. Works involving fluid media, porous media and nanofluids (with magnetohydrodynamics) have been highlighted. Various numerical and experimental works on mixed convection have been elucidated. Flow and thermal maps associated with the heat transfer rate for a few representative cases of unified models [Models 1–10] have been elucidated involving specific dimensionless numbers.

Originality/value

This review paper will provide guidelines for optimal design/operation involving mixed convection processing applications.

Details

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

Keywords

To view the access options for this content please click here
Article
Publication date: 9 March 2020

Kumar Sanjay Sawarni, Sivasankaran Narayanasamy and Kanagaraj Ayyalusamy

This paper aims to investigate the impact of the efficiency of working capital management (WCM) on the performance of a sample of Indian companies and explore how the…

Abstract

Purpose

This paper aims to investigate the impact of the efficiency of working capital management (WCM) on the performance of a sample of Indian companies and explore how the nature of the firm's business influences the significance and direction of this impact.

Design/methodology/approach

The data for this study were collected for the period of 2012–2018 for 414 non-financial firms listed on the Bombay Stock exchange. Fixed-effect regression models were run by taking Tobin's Q and return on equity (ROE) as dependent variables, and net trade cycle (NTC) and its components as explanatory variables in the presence of liquidity, leverage, size, age and growth as control variables. Sample firms were segregated into manufacturing, trading and service groups, and regression models were used for all the groups to understand the effect of the nature of a firm's business.

Findings

WCM efficiency has a significant impact on the performance of the sample firms. Non-financial Indian firms deliver better financial performance by maintaining lower NTC. Like NTC, its components also impact firm value and profitability. The results report that the significance of the relationship varies depending upon the nature of the firm's business.

Originality/value

The previous research studies had not used a sample of large number of Indian firms. Unlike previous studies, this study reports the influence of the nature of business on the relationship between WCM and firm performance. Further, this paper also examines how the individual components of working capital influence the performance of Indian firms.

Details

International Journal of Productivity and Performance Management, vol. 70 no. 1
Type: Research Article
ISSN: 1741-0401

Keywords

1 – 10 of 117