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Muneer A Ismael - One of the best experts on this subject based on the ideXlab platform.

  • Thermal analysis of nanofluid saturated in inclined Porous Cavity cooled by rotating active cylinder subjected to convective condition
    Journal of Thermal Analysis and Calorimetry, 2020
    Co-Authors: Mohammed Y. Jabbar, Hameed K. Hamzah, Farooq H. Ali, Saba Y. Ahmed, Muneer A Ismael
    Abstract:

    Convective heat transfer in a Porous Cavity conjugated with an active rotating cylinder is investigated in this paper. Copper–water nanofluid fills the Porous Cavity. The rotating active cylinder is positioned in such a way conveying heat from the Cavity and discharges it outside. The vertical walls of the Cavity are thermally insulated while the bottom wall is moving to the right and kept at a constant high temperature. The governing equations are facilitated with the ability to study the tilt of the cylinder-Cavity assembly. The effects of Richardson number, Darcy number, inclination angle, conductivity ratio, rotational speed, and nanofluid volume fraction are studied at a constant Rayleigh number of 10^5. Galerkin finite element method of weak formulation is used to solve the dimensionless governing equation with appropriate boundary conditions. Darcy–Brinkman–Forchheimer model is adopted to govern the flow inside Porous medium. Results show that the rotation of the cylinder can enlarge the average Nusselt number more than 223%, while ten times increase of thermal conductivity ratio amplifies Nusselt number by 136%. It is also found that the Richardson number plays an adverse role on the average Nusselt number. Physical explanations and thorough validations are given in the paper.

  • conjugate heat transfer in a Porous Cavity filled with nanofluids and heated by a triangular thick wall
    International Journal of Thermal Sciences, 2013
    Co-Authors: Ali J. Chamkha, Muneer A Ismael
    Abstract:

    The conjugate natural convection–conduction heat transfer in a square domain composed of nanofluids filled Porous Cavity heated by a triangular solid wall is studied under steady-state conditions. The vertical and horizontal walls of the triangular solid wall are kept isothermal and at the same hot temperature Th. The other boundaries surrounding the Porous Cavity are kept adiabatic except the right vertical wall where it is kept isothermally at the lower temperature Tc. Equations governing the heat transfer in the triangular wall and heat and nanofluid flow, based on the Darcy model, in the nanofluid-saturated Porous medium together with the derived relation of the interface temperature are solved numerically using the over-successive relaxation finite-difference method. A temperature independent nanofluids properties model is adopted. Three nanoparticle types dispersed in one base fluid (water) are investigated. The investigated parameters are the nanoparticles volume fraction φ (0–0.2), Rayleigh number Ra (10–1000), solid wall to base-fluid saturated Porous medium thermal conductivity ratio Kro (0.44, 1, 23.8), and the triangular wall thickness D (0.1–1). The results are presented in the conventional form; contours of streamlines and isotherms and the local and average Nusselt numbers. At a very low Rayleigh number Ra = 10, a significant enhancement in heat transfer within the Porous Cavity with φ is observed. Otherwise, the heat transfer may be enhanced or deteriorated with φ depending on the wall thickness D and the Rayleigh number Ra. At high Rayleigh numbers and low conductivity ratios, critical values of D, regardless of φ, are observed and accounted.

  • conjugate heat transfer in a Porous Cavity heated by a triangular thick wall
    Numerical Heat Transfer Part A-applications, 2013
    Co-Authors: Ali J. Chamkha, Muneer A Ismael
    Abstract:

    The conjugate natural convection-conduction heat transfer in a square domain composed of a Cavity heated by a triangular solid wall is studied under steady state condition. The vertical and horizontal walls of the triangular solid are kept isothermal and at the same hot temperature T h . The other boundaries surrounding the Porous Cavity are kept adiabatic except the right vertical wall, where it is kept isothermally at the lower temperature T c . Equations governing the heat transfer in the triangular wall and heat and fluid flow, based on the Darcy model, in the fluid-saturated Porous medium together with the derived relation of the interface temperature are solved numerically using the second order central differences finite difference scheme with the successive over relaxation (SOR) method. The investigated parameters are the Rayleigh number Ra (100-1000), solid to fluid saturated Porous medium thermal conductivity ratio Kr (0.1–10), and the triangular wall thickness D (0.05-1). The results are presen...

Ali J. Chamkha - One of the best experts on this subject based on the ideXlab platform.

  • Magnetohydrodynamic Mixed Convection and Entropy Analysis of Nanofluid in Gamma-Shaped Porous Cavity
    Journal of Thermophysics and Heat Transfer, 2020
    Co-Authors: Ali J. Chamkha, M. A. Mansour, Ahmed M. Rashad, Hadi Kargarsharifabad, T. Armaghani
    Abstract:

    The entropy generation due to magnetohydrodynamic mixed convection flow and heat transfer in a Gamma-shaped Porous Cavity is explored in this research by the finite volume technique. There exists a...

  • Heat transfer enhancement of mixed convection in an inclined Porous Cavity using Cu-water nanofluid
    Advanced Powder Technology, 2018
    Co-Authors: M. Rajarathinam, N. Nithyadevi, Ali J. Chamkha
    Abstract:

    Abstract In this paper, mixed convection of Cu-nanofluid in an inclined fluid-saturated Porous Cavity is numerically analyzed by considering three different cases depending on the direction of moving wall(s). The equations of nanofluid-saturated Porous medium can be derived by the Darcy-Brinkman-Forchheimer model and are solved using the SIMPLE algorithm. The effect of various non-dimensional parameter such as the Richardson number, Darcy number, inclination angle, solid volume fraction and three different cases are carefully analyzed. The obtained results are presented in the form of streamlines, isotherms, mid-height velocity profiles and average Nusselt number. It is found that the flow and heat transfer play a significant role with the direction of the moving wall(s).

  • conjugate heat transfer in a Porous Cavity filled with nanofluids and heated by a triangular thick wall
    International Journal of Thermal Sciences, 2013
    Co-Authors: Ali J. Chamkha, Muneer A Ismael
    Abstract:

    The conjugate natural convection–conduction heat transfer in a square domain composed of nanofluids filled Porous Cavity heated by a triangular solid wall is studied under steady-state conditions. The vertical and horizontal walls of the triangular solid wall are kept isothermal and at the same hot temperature Th. The other boundaries surrounding the Porous Cavity are kept adiabatic except the right vertical wall where it is kept isothermally at the lower temperature Tc. Equations governing the heat transfer in the triangular wall and heat and nanofluid flow, based on the Darcy model, in the nanofluid-saturated Porous medium together with the derived relation of the interface temperature are solved numerically using the over-successive relaxation finite-difference method. A temperature independent nanofluids properties model is adopted. Three nanoparticle types dispersed in one base fluid (water) are investigated. The investigated parameters are the nanoparticles volume fraction φ (0–0.2), Rayleigh number Ra (10–1000), solid wall to base-fluid saturated Porous medium thermal conductivity ratio Kro (0.44, 1, 23.8), and the triangular wall thickness D (0.1–1). The results are presented in the conventional form; contours of streamlines and isotherms and the local and average Nusselt numbers. At a very low Rayleigh number Ra = 10, a significant enhancement in heat transfer within the Porous Cavity with φ is observed. Otherwise, the heat transfer may be enhanced or deteriorated with φ depending on the wall thickness D and the Rayleigh number Ra. At high Rayleigh numbers and low conductivity ratios, critical values of D, regardless of φ, are observed and accounted.

  • conjugate heat transfer in a Porous Cavity heated by a triangular thick wall
    Numerical Heat Transfer Part A-applications, 2013
    Co-Authors: Ali J. Chamkha, Muneer A Ismael
    Abstract:

    The conjugate natural convection-conduction heat transfer in a square domain composed of a Cavity heated by a triangular solid wall is studied under steady state condition. The vertical and horizontal walls of the triangular solid are kept isothermal and at the same hot temperature T h . The other boundaries surrounding the Porous Cavity are kept adiabatic except the right vertical wall, where it is kept isothermally at the lower temperature T c . Equations governing the heat transfer in the triangular wall and heat and fluid flow, based on the Darcy model, in the fluid-saturated Porous medium together with the derived relation of the interface temperature are solved numerically using the second order central differences finite difference scheme with the successive over relaxation (SOR) method. The investigated parameters are the Rayleigh number Ra (100-1000), solid to fluid saturated Porous medium thermal conductivity ratio Kr (0.1–10), and the triangular wall thickness D (0.05-1). The results are presen...

Ioan Pop - One of the best experts on this subject based on the ideXlab platform.

  • MHD natural convection in a square Porous Cavity filled with a water-based magnetic fluid in the presence of geothermal viscosity
    International Journal of Numerical Methods for Heat & Fluid Flow, 2018
    Co-Authors: Mikhail A. Sheremet, Marina S. Astanina, Ioan Pop
    Abstract:

    Purpose The purpose of this paper is a numerical analysis of natural convection in a square Porous Cavity filled with a water-based magnetic fluid of geothermal viscosity under the effect of inclined uniform magnetic field. Design/methodology/approach The domain of interest includes the square Porous Cavity filled with a water-based magnetic fluid (W40). Horizontal walls are supposed to be adiabatic, while right vertical wall is kept at constant low temperature and left vertical wall is kept at constant high temperature. An inclined uniform magnetic field affects the fluid flow and heat transfer inside the Cavity. The viscosity of the working fluid is proportional to the linearly decreasing function of depth (vertical coordinate) and inversely proportional to the linear function of temperature. It is assumed in the analysis that the flow is laminar. The fluid is Newtonian and the Boussinesq approximation is valid. The governing equations have been discretized using the finite difference method with the uniform grid. Simulations have been carried out for different values of the Rayleigh number, Hartmann number, Darcy number, magnetic field inclination angle and viscosity variation parameters. Findings It has been revealed that an increase in the viscosity parameters leads to the heat transfer enhancement and convective flow intensification. At the same time, this intensification is more essential for high values of the Rayleigh number. Originality/value The originality of this work is to analyze MHD natural convection in a square Porous Cavity filled with a water-based magnetic fluid of geothermal viscosity. The results would benefit scientists and engineers to become familiar with the analysis of convective heat and mass transfer in nanofluids, and the way to predict the properties of nanofluid convective flow in advanced technical systems, in industrial sectors including transportation, power generation, chemical sectors and electronics.

  • unsteady conjugate natural convection in a Porous Cavity boarded by two vertical finite thickness walls
    International Communications in Heat and Mass Transfer, 2017
    Co-Authors: Hossein Zargartalebi, Khalil Khanafer, Mohammad Ghalambaz, Ioan Pop
    Abstract:

    Abstract The objective of this study is to investigate unsteady conjugate natural convection in a Porous Cavity sandwiched by finite conductive walls considering time-periodic boundary conditions and local thermal non-equilibrium. The top and bottom boundaries are assumed to be isolated and the continuity of temperature and heat transfer are considered in interface boundaries. The effect of varying a plethora of parameters such as Rayleigh number, Thermal conductivity ratio, wall thickness, and non-dimensional frequency on the streamlines, isotherms, and Nusselt number has been studied. It is shown that, apart from non-dimensional frequency and wall thickness, the amplitude of periodic fluid Nusselt number is an increasing function of all aforementioned parameters. Furthermore, aside from Rayleigh number and heat transfer coefficient, the behavior of the solid Nusselt number is the same as fluid Nusselt number. Eventually, the time-averaged Nusselt number and heat transfer through the vertical walls for different values of non-dimensional frequencies are calculated.

  • Natural convection in a wavy open Porous Cavity filled with a nanofluid: Tiwari and Das’ nanofluid model
    The European Physical Journal Plus, 2016
    Co-Authors: Mikhail A. Sheremet, Ioan Pop, Aroon Shenoy
    Abstract:

    Natural convective heat transfer and fluid flow in an open Porous Cavity filled with a nanofluid is studied numerically using the Tiwari and Das nanofluid model. The transport equations for mass, momentum and energy formulated in dimensionless stream function and temperature are solved numerically using a second-order accurate finite difference method. Particular efforts are focused on the effects of the governing parameters on the heat and fluid flow. It is found that an increase in undulation number of the wavy vertical wall leads to an attenuation of convective flow and a decrease in the heat transfer rate.

  • steady state conjugate natural convection in a fluid saturated Porous Cavity
    International Journal of Heat and Mass Transfer, 2008
    Co-Authors: Abdalla M Alamiri, Khalil Khanafer, Ioan Pop
    Abstract:

    Abstract The current numerical investigation addresses the wall heat conduction effect on the natural-convection heat transfer within a two-dimensional Cavity, which is filled with a fluid-saturated Porous medium. The problem configuration consists of two insulated horizontal walls of finite thickness and two vertical walls which are maintained at constant but different temperatures. The generalized model of the momentum equation, which is also known as the Forchheimer–Brinkman-extended Darcy model, is used in representing the fluid motion inside the Porous Cavity. The local thermal equilibrium condition is assumed to be valid for the range of the thermophysical parameters considered in the present investigation. The steady-state solution is sought from the undergoing investigation. The momentum and energy transport processes within the Porous Cavity is examined through depicting the streamlines and isotherms for different domains of a selected dimensionless groups. These dimensionless groups and their respective domains are as follows: W = 0.0075 – 0.2 , K r = 1 – 10 , k s / k f = 0.1 – 100 , Ra = 10 4 – 10 6 , Da = 10 - 5 – 10 - 1 , e = 0.25 – 0.95 and AR = 0.25 – 2 . The significance of varying these parameters on the predicated average Nusselt number is highlighted and discussed. Finally, the investigation is concluded by presenting the sensitivity of the interface temperature upon varying the above dimensionless groups.

Mikhail A. Sheremet - One of the best experts on this subject based on the ideXlab platform.

  • MHD natural convection in a square Porous Cavity filled with a water-based magnetic fluid in the presence of geothermal viscosity
    International Journal of Numerical Methods for Heat & Fluid Flow, 2018
    Co-Authors: Mikhail A. Sheremet, Marina S. Astanina, Ioan Pop
    Abstract:

    Purpose The purpose of this paper is a numerical analysis of natural convection in a square Porous Cavity filled with a water-based magnetic fluid of geothermal viscosity under the effect of inclined uniform magnetic field. Design/methodology/approach The domain of interest includes the square Porous Cavity filled with a water-based magnetic fluid (W40). Horizontal walls are supposed to be adiabatic, while right vertical wall is kept at constant low temperature and left vertical wall is kept at constant high temperature. An inclined uniform magnetic field affects the fluid flow and heat transfer inside the Cavity. The viscosity of the working fluid is proportional to the linearly decreasing function of depth (vertical coordinate) and inversely proportional to the linear function of temperature. It is assumed in the analysis that the flow is laminar. The fluid is Newtonian and the Boussinesq approximation is valid. The governing equations have been discretized using the finite difference method with the uniform grid. Simulations have been carried out for different values of the Rayleigh number, Hartmann number, Darcy number, magnetic field inclination angle and viscosity variation parameters. Findings It has been revealed that an increase in the viscosity parameters leads to the heat transfer enhancement and convective flow intensification. At the same time, this intensification is more essential for high values of the Rayleigh number. Originality/value The originality of this work is to analyze MHD natural convection in a square Porous Cavity filled with a water-based magnetic fluid of geothermal viscosity. The results would benefit scientists and engineers to become familiar with the analysis of convective heat and mass transfer in nanofluids, and the way to predict the properties of nanofluid convective flow in advanced technical systems, in industrial sectors including transportation, power generation, chemical sectors and electronics.

  • Transient natural convection with temperature-dependent viscosity in a square partially Porous Cavity having a heat-generating source
    Numerical Heat Transfer Part A: Applications, 2018
    Co-Authors: Marina S. Astanina, Mikhail A. Sheremet, Jawali C. Umavathi
    Abstract:

    A numerical study is performed on the transient natural convection with a temperature-dependent viscosity inside a square partially Porous Cavity with a local heat-generating and heat-conducting so...

  • Natural convection in a wavy open Porous Cavity filled with a nanofluid: Tiwari and Das’ nanofluid model
    The European Physical Journal Plus, 2016
    Co-Authors: Mikhail A. Sheremet, Ioan Pop, Aroon Shenoy
    Abstract:

    Natural convective heat transfer and fluid flow in an open Porous Cavity filled with a nanofluid is studied numerically using the Tiwari and Das nanofluid model. The transport equations for mass, momentum and energy formulated in dimensionless stream function and temperature are solved numerically using a second-order accurate finite difference method. Particular efforts are focused on the effects of the governing parameters on the heat and fluid flow. It is found that an increase in undulation number of the wavy vertical wall leads to an attenuation of convective flow and a decrease in the heat transfer rate.

  • Thermo-Bioconvection in a Square Porous Cavity Filled by Oxytactic Microorganisms
    Transport in Porous Media, 2014
    Co-Authors: Mikhail A. Sheremet, I. Pop
    Abstract:

    This paper studies the thermo-bioconvection in a square Porous Cavity filled by oxytactic microorganisms. The Darcy model with Boussinesq approximation has been used to solve the flow and heat and mass transfer in the Porous region. The governing equations formulated in terms of the dimensionless stream function, temperature and concentration have been solved using the finite difference method. Comparison with results from the open literature of the mean Nusselt number for a square Cavity filled with a regular Porous medium is made. It is shown that the results are in very good agreement. The main objective was to investigate the influence of the traditional Rayleigh number Ra = 10, 100, bioconvection Rayleigh number Rb = 10, 100, Lewis number Le = 1, 10, and Peclet number Pe = 0.1, 1 on the fluid flow and heat and mass transfer. Comprehensive analysis of an effect of these key parameters on the Nusselt and Sherwood numbers at the vertical walls has been conducted.

Masaaki Ishikawa - One of the best experts on this subject based on the ideXlab platform.

  • Experimental Study of Effect of Jets Injected into Supersonic Main Flow on Porous Cavity
    29th International Symposium on Shock Waves 2, 2015
    Co-Authors: Nao Kuniyoshi, Minoru Yaga, Isao Teruya, Masaaki Ishikawa
    Abstract:

    In this study, the interaction between the supersonic main duct flow and jet surrounded by a Porous Cavity was experimentally investigated by means of schlieren flow visualization and measurements of flow direction in a Cavity underneath of jets. The detection of flow directions was done with so called thermal tuft probe that has two heat sensors and one heat source middle of the two sensors. The parameters of the experiments are jet arrangements and pressure ratio defined by the ratio of total pressure in the settling chamber to atmospheric pressure. As a result, the backward flow in the Cavity is confirmed in case of jet injections. Moreover, it is found that the change in the flow direction has dominant frequency between 300HZ and 400Hz only when the starting shock wave exists around the Porous Cavity

  • Experimental Study of unsteady supersonic flow interacting with Porous Cavity and jets or rods
    Journal of Thermal Science, 2014
    Co-Authors: Nao Kuniyoshi, Minoru Yaga, Isao Teruya, Masaaki Ishikawa
    Abstract:

    In this study, an experiment was performed to clarify the flow field, in which the jets were normally injected into a main supersonic flow surrounded by a Porous Cavity, and this report figures out interaction between starting shock wave and Porous Cavity. In the experiment, a Porous Cavity is attached to a main duct and jets and rods are inserted to the main duct on the Porous Cavity. To reveal this flow field, the thermal tuft probe was adopted to experimentally investigate the flow in the Cavity. In the experiments, the effect of the Porous Cavity with jets or rods on the flow field is studied by means of visualization of schlieren method with a high speed camera and measurement of Cavity flow with thermal tuft probe. As a results, frequency analysis of output of the thermal tuft probe revealed that some clear dominant frequencies were confirmed when the starting shock wave existed around the Porous Cavity in all cases of jets and rods arrangements. Moreover, visualization of schlieren method with a high speed camera clarified that a starting shock wave had the same dominant frequencies as that of the flow fluctuation in the Cavity only around the Cavity.

  • Experimental study of interaction between supersonic duct flow and jets surrounded by the Porous Cavity
    Experimental Thermal and Fluid Science, 2012
    Co-Authors: Nao Kuniyoshi, Minoru Yaga, Isao Teruya, Akito Koda, Masaaki Ishikawa
    Abstract:

    Abstract In the experiments, the effect of the combination of jets and a Porous Cavity on the flow field is studied by means of visualization of schlieren method and the measurements of wall static pressures and the flow direction in the Cavity with the thermal tuft probe which is introduced in this paper. These measurements are performed simultaneously, which allow us to evaluate the effect of the jets and the Porous Cavity. Three cases for the jet arrangements are tested in this experiments. That is (1) no-jets issued only with a Porous wall as a reference, (2) a single jet at the middle of the Porous region, and (3) three jets in the Porous region aligned spanwise to the main flow. As a result, the thermal tuft probe in the Cavity is found to be non-disturbing detecting device to the whole flow field according to the shock locations and the wall static pressure measurements. It is also found that the flow direction in the Cavity is greatly influenced by the starting shock wave and jet arrangements. The flow direction at the measurement positions in the Cavity is always opposite to the main flow, as long as the starting shock wave is located upstream region of the Porous wall for all jet patterns as well as the no-jets case. Moreover, in case that the starting shock wave exists downstream of the Porous region, that is, the state of the main flow in the Porous wall region is supersonic state, the flow direction in the Cavity continues to be opposite to the main flow for a single jet issued at the middle of the Porous wall. The results in this paper show that the combination of the jets and the Porous Cavity affects the shock positions and the flow direction in the Cavity, which could be one of the promising techniques for the control of the flow field.