Toru Fusegi - Academia.edu (original) (raw)

Papers by Toru Fusegi

Proceeding of International Heat Transfer Conference 8

Fire Safety Science, 1991

A high-resolution, 3-D finite-difference numerical study is performed on interactions of natural ... more A high-resolution, 3-D finite-difference numerical study is performed on interactions of natural convection and surface/gas/soot radiation in a differentially heated cubical enclosure, which may be regarded as a simplified model for compartment fires. A robust gas/soot radiation model used in the analysis is based on the PI-differential approximation method and the weighted sum of gray gas model. The 3-D characteristics of the thermal and flow fields are examined in detail by the state-of-the-art 3-D numerical visualization techniques. The effects of each mode of radiation are described. Overall, radiation is found to enhance the three-dimensionalities of the fields.

Springer eBooks, 1991

A high-resolution, three-dimensional finite difference numerical study was performed on interacti... more A high-resolution, three-dimensional finite difference numerical study was performed on interactions of natural convection and surface/gas/soot radiation in a differentially heated cubical enclosure over the Rayleigh number of 105 ≤ Ra ≤ 109. A robust gas/soot radiation model used in the analysis was based on the P1-differential approximation method and the weighted sum of gray gas model. The three-dimensional characteristics of the thermal and flow fields were examined in detail by the state-of-the-art three-dimensional numerical visualization techniques. The effects of each mode of radiation were described. Overall, radiation was found to enhance the three-dimensionalities of the fields.

Fire Science and Technology, 1988

Physics of Fluids, 2000

The behavior of thermoacoustic waves in a nitrogen-filled two-dimensional cavity is numerically s... more The behavior of thermoacoustic waves in a nitrogen-filled two-dimensional cavity is numerically studied in order to investigate how these waves may be used as an effective heat removal mechanism. The compressible, unsteady Navier–Stokes equations were solved for a series of initial conditions by combining a flux-corrected transport algorithm for convection with models for temperature-dependent viscosity and thermal conduction. By considering a one-dimensional test problem and comparing the results to existing data, the accuracy of the present numerical method is verified. In the problems considered, the vertical walls of a cavity were heated or cooled to generate the thermoacoustic waves. Both impulsive and gradual changes of the wall temperatures were considered. When the vertical wall was heated impulsively and nonuniformly, the waves induced two-dimensional flows within the enclosure. The observed thermoacoustic waves oscillate and eventually decay due to viscous and heat dissipa...

Numerical Heat Transfer, Part B: Fundamentals, 1986

Numerical Heat Transfer, Part B: Fundamentals, 1986

Page 1. Numerical Heat Transfer, vol. 9, pp. 591-604, 1986 MIXED-CONVECTION FLOWS WITHIN A HORIZO... more Page 1. Numerical Heat Transfer, vol. 9, pp. 591-604, 1986 MIXED-CONVECTION FLOWS WITHIN A HORIZONTAL CONCENTRIC ANNULUS WITH A HEATED ROTATING INNER CYLINDER 1 Toru Fusegi, Bakhtier Farouk ...

Journal of Heat Transfer, 1990

ABSTRACT

Journal of Heat Transfer, 1992

The phenomenon of natural convection in a square cavity filled with a copper-water nanofluid is i... more The phenomenon of natural convection in a square cavity filled with a copper-water nanofluid is investigated numerically. The studied domain is a square cavity with hot and cold isothermal walls at x = 0 and x = L, respectively, while the other walls are adiabatic. The fins are considered perfectly conductive with different lengths (L f) and positioned at different locations. We examined the situation for Rayleigh numbers ranging between 10 4 and 10 6. The governing equations are expressed in the vorticity, stream function, and temperature formulation. The system of equations was solved by the finite difference method, using the upwind scheme. The computation code thus developed was used to analyze the effect of the different locations of the fins on the thermal performances. The obtained results were validated by comparing with those of a previously published work and with those obtained using COMSOL Multiphysics. It has been found that adding fins on the cold and adiabatic walls results in an increase in the average Nusselt number, while it decreases when the fin is located on the hot wall. That is to say, placing the fins on the cold and adiabatic walls increases the thermal performances of the transfer.

Journal of Computational Physics, 1986

ABSTRACT

International Journal of Heat and Mass Transfer, 1993

International Journal of Heat and Fluid Flow, 1992

Abstract A high-resolution, finite-difference numerical study is made of three-dimensional natura... more Abstract A high-resolution, finite-difference numerical study is made of three-dimensional natural convection in a cubical enclosure. The two vertical sidewalls of the enclosure are differentially heated. An internal partition of varying size and shape is located at the mid-plane of the cavity. Comprehensive numerical solutions to the time-dependent Navier-Stokes equations are acquired by using a control volume-based computational procedure. Two Rayleigh numbers, 10 7 and 5 × 10 9 , are considered for the enclosure filled with air (Pr=0.71). The salient three-dimensional flow characteristics are illustrated for two selected types of the partition geometry. The results clearly demonstrate the prominent three-dimensional features in the partitioned enclosure. Elaborate numerical visualization efforts have been conducted, and both the flow and thermal fields are portrayed in sufficient detail. The effects of the partition geometry on the three-dimensional flow properties are scrutinized.

International Journal of Heat and Fluid Flow, 1997

A numerical study is performed on the fully developed forced-convection heat transfer in a groove... more A numerical study is performed on the fully developed forced-convection heat transfer in a grooved channel with a heated lower plate. Periodic flows are forced through the channel. The time-periodic variations of externally sustained pressure gradients imposed upon the throughflow have significant bearing on the interaction between the throughflow in the channel and the recirculatory flow inside the cavity. Aided by this interaction, convective heat transfer is pronounced for Re >_ 102, where Re is the oscillatory flow Reynolds number. As the Womersley n'umber increases, the communication between the heated fluid inside the cavity and the thi'oughflow is promoted, leading to heat transfer enhancement.

International Journal for Numerical Methods in Fluids, 1985

A relatively novel formulation of the Navier‐Stokes equations is used for obtaining solutions of ... more A relatively novel formulation of the Navier‐Stokes equations is used for obtaining solutions of two dimensional incompressible fluid flow and convective heat transfer problems. A vorticity transport equation along with two Poisson equations for the velocity components and the energy equation are solved by a finite difference scheme. A coupled solution procedure is used for solving simultaneously the dependent variables along a line, using a block tridiagonal matrix algorithm. The formulation is found to be stable and has features that may be desirable for solving a wide variety of flow and heat transfer problems.

Fluid Dynamics Research, 1991

A high-resolution, three-dimensional finite-difference numerical study of natural convection flow... more A high-resolution, three-dimensional finite-difference numerical study of natural convection flows of a viscous fluid in a differentially heated cubical box is reported. The vertical sidewalls of the enclosure are maintained at constant temperatures of different values. The other vertical walls (the end walls) are thermally insulated. For the horizontal walls, two kinds of thermal boundary conditions are specified: adiabatic and perfectly conducting. Computations have been performed for an air-filled cavity for Rayleigh numbers of 10 5 and 10 6. The specific effects of the horizontal thermal boundary conditions on the flow structure are examined in detail. In the case of conducting walls, heat transfer through the horizontal walls enhances the convective flow activities. The numerically predicted velocity and temperature profiles in the symmetry planes are consistent with previous experimental measurements and computations.

Applied Scientific Research, 1992

A high-resolution, finite-difference numerical study is carried out of three-dimensional unsteady... more A high-resolution, finite-difference numerical study is carried out of three-dimensional unsteady periodic natural convection of air in a cubical enclosure at the Rayleigh number of 8.5 × 106. The enclosure is subjected to differential heating at the two vertical side walls. The other vertical walls are insulated. A linear temperature profile is specified at the thermally-conducting horizontal walls. Flow details in the three-dimensional field are captured by elaborate post-processing of the computational results, for which the state-of-the-art numerical visualization techniques are utilized. The three-dimensionality of the mean flow fields is observed to be confined into narrow regions near the end walls. The time-dependent solutions clearly indicate the periodic nature of the flow. The oscillation frequency is in close agreement with the previous experimental measurements reported in the literature.

International Journal for Numerical Methods in Fluids, 1991

... These irregularities were smoothed out in the results obtained with the k-& turbulenc... more ... These irregularities were smoothed out in the results obtained with the k-& turbulence model" in the case of an enclosure with a depth-to-width ratio of 20 at Ra= lolo. Page 7. 3D SIMULATIONS OF NATURAL CONVECTION 863 ...

Proceeding of International Heat Transfer Conference 8

Fire Safety Science, 1991

A high-resolution, 3-D finite-difference numerical study is performed on interactions of natural ... more A high-resolution, 3-D finite-difference numerical study is performed on interactions of natural convection and surface/gas/soot radiation in a differentially heated cubical enclosure, which may be regarded as a simplified model for compartment fires. A robust gas/soot radiation model used in the analysis is based on the PI-differential approximation method and the weighted sum of gray gas model. The 3-D characteristics of the thermal and flow fields are examined in detail by the state-of-the-art 3-D numerical visualization techniques. The effects of each mode of radiation are described. Overall, radiation is found to enhance the three-dimensionalities of the fields.

Springer eBooks, 1991

A high-resolution, three-dimensional finite difference numerical study was performed on interacti... more A high-resolution, three-dimensional finite difference numerical study was performed on interactions of natural convection and surface/gas/soot radiation in a differentially heated cubical enclosure over the Rayleigh number of 105 ≤ Ra ≤ 109. A robust gas/soot radiation model used in the analysis was based on the P1-differential approximation method and the weighted sum of gray gas model. The three-dimensional characteristics of the thermal and flow fields were examined in detail by the state-of-the-art three-dimensional numerical visualization techniques. The effects of each mode of radiation were described. Overall, radiation was found to enhance the three-dimensionalities of the fields.

Fire Science and Technology, 1988

Physics of Fluids, 2000

The behavior of thermoacoustic waves in a nitrogen-filled two-dimensional cavity is numerically s... more The behavior of thermoacoustic waves in a nitrogen-filled two-dimensional cavity is numerically studied in order to investigate how these waves may be used as an effective heat removal mechanism. The compressible, unsteady Navier–Stokes equations were solved for a series of initial conditions by combining a flux-corrected transport algorithm for convection with models for temperature-dependent viscosity and thermal conduction. By considering a one-dimensional test problem and comparing the results to existing data, the accuracy of the present numerical method is verified. In the problems considered, the vertical walls of a cavity were heated or cooled to generate the thermoacoustic waves. Both impulsive and gradual changes of the wall temperatures were considered. When the vertical wall was heated impulsively and nonuniformly, the waves induced two-dimensional flows within the enclosure. The observed thermoacoustic waves oscillate and eventually decay due to viscous and heat dissipa...

Numerical Heat Transfer, Part B: Fundamentals, 1986

Numerical Heat Transfer, Part B: Fundamentals, 1986

Page 1. Numerical Heat Transfer, vol. 9, pp. 591-604, 1986 MIXED-CONVECTION FLOWS WITHIN A HORIZO... more Page 1. Numerical Heat Transfer, vol. 9, pp. 591-604, 1986 MIXED-CONVECTION FLOWS WITHIN A HORIZONTAL CONCENTRIC ANNULUS WITH A HEATED ROTATING INNER CYLINDER 1 Toru Fusegi, Bakhtier Farouk ...

Journal of Heat Transfer, 1990

ABSTRACT

Journal of Heat Transfer, 1992

The phenomenon of natural convection in a square cavity filled with a copper-water nanofluid is i... more The phenomenon of natural convection in a square cavity filled with a copper-water nanofluid is investigated numerically. The studied domain is a square cavity with hot and cold isothermal walls at x = 0 and x = L, respectively, while the other walls are adiabatic. The fins are considered perfectly conductive with different lengths (L f) and positioned at different locations. We examined the situation for Rayleigh numbers ranging between 10 4 and 10 6. The governing equations are expressed in the vorticity, stream function, and temperature formulation. The system of equations was solved by the finite difference method, using the upwind scheme. The computation code thus developed was used to analyze the effect of the different locations of the fins on the thermal performances. The obtained results were validated by comparing with those of a previously published work and with those obtained using COMSOL Multiphysics. It has been found that adding fins on the cold and adiabatic walls results in an increase in the average Nusselt number, while it decreases when the fin is located on the hot wall. That is to say, placing the fins on the cold and adiabatic walls increases the thermal performances of the transfer.

Journal of Computational Physics, 1986

ABSTRACT

International Journal of Heat and Mass Transfer, 1993

International Journal of Heat and Fluid Flow, 1992

Abstract A high-resolution, finite-difference numerical study is made of three-dimensional natura... more Abstract A high-resolution, finite-difference numerical study is made of three-dimensional natural convection in a cubical enclosure. The two vertical sidewalls of the enclosure are differentially heated. An internal partition of varying size and shape is located at the mid-plane of the cavity. Comprehensive numerical solutions to the time-dependent Navier-Stokes equations are acquired by using a control volume-based computational procedure. Two Rayleigh numbers, 10 7 and 5 × 10 9 , are considered for the enclosure filled with air (Pr=0.71). The salient three-dimensional flow characteristics are illustrated for two selected types of the partition geometry. The results clearly demonstrate the prominent three-dimensional features in the partitioned enclosure. Elaborate numerical visualization efforts have been conducted, and both the flow and thermal fields are portrayed in sufficient detail. The effects of the partition geometry on the three-dimensional flow properties are scrutinized.

International Journal of Heat and Fluid Flow, 1997

A numerical study is performed on the fully developed forced-convection heat transfer in a groove... more A numerical study is performed on the fully developed forced-convection heat transfer in a grooved channel with a heated lower plate. Periodic flows are forced through the channel. The time-periodic variations of externally sustained pressure gradients imposed upon the throughflow have significant bearing on the interaction between the throughflow in the channel and the recirculatory flow inside the cavity. Aided by this interaction, convective heat transfer is pronounced for Re >_ 102, where Re is the oscillatory flow Reynolds number. As the Womersley n'umber increases, the communication between the heated fluid inside the cavity and the thi'oughflow is promoted, leading to heat transfer enhancement.

International Journal for Numerical Methods in Fluids, 1985

A relatively novel formulation of the Navier‐Stokes equations is used for obtaining solutions of ... more A relatively novel formulation of the Navier‐Stokes equations is used for obtaining solutions of two dimensional incompressible fluid flow and convective heat transfer problems. A vorticity transport equation along with two Poisson equations for the velocity components and the energy equation are solved by a finite difference scheme. A coupled solution procedure is used for solving simultaneously the dependent variables along a line, using a block tridiagonal matrix algorithm. The formulation is found to be stable and has features that may be desirable for solving a wide variety of flow and heat transfer problems.

Fluid Dynamics Research, 1991

A high-resolution, three-dimensional finite-difference numerical study of natural convection flow... more A high-resolution, three-dimensional finite-difference numerical study of natural convection flows of a viscous fluid in a differentially heated cubical box is reported. The vertical sidewalls of the enclosure are maintained at constant temperatures of different values. The other vertical walls (the end walls) are thermally insulated. For the horizontal walls, two kinds of thermal boundary conditions are specified: adiabatic and perfectly conducting. Computations have been performed for an air-filled cavity for Rayleigh numbers of 10 5 and 10 6. The specific effects of the horizontal thermal boundary conditions on the flow structure are examined in detail. In the case of conducting walls, heat transfer through the horizontal walls enhances the convective flow activities. The numerically predicted velocity and temperature profiles in the symmetry planes are consistent with previous experimental measurements and computations.

Applied Scientific Research, 1992

A high-resolution, finite-difference numerical study is carried out of three-dimensional unsteady... more A high-resolution, finite-difference numerical study is carried out of three-dimensional unsteady periodic natural convection of air in a cubical enclosure at the Rayleigh number of 8.5 × 106. The enclosure is subjected to differential heating at the two vertical side walls. The other vertical walls are insulated. A linear temperature profile is specified at the thermally-conducting horizontal walls. Flow details in the three-dimensional field are captured by elaborate post-processing of the computational results, for which the state-of-the-art numerical visualization techniques are utilized. The three-dimensionality of the mean flow fields is observed to be confined into narrow regions near the end walls. The time-dependent solutions clearly indicate the periodic nature of the flow. The oscillation frequency is in close agreement with the previous experimental measurements reported in the literature.

International Journal for Numerical Methods in Fluids, 1991

... These irregularities were smoothed out in the results obtained with the k-& turbulenc... more ... These irregularities were smoothed out in the results obtained with the k-& turbulence model" in the case of an enclosure with a depth-to-width ratio of 20 at Ra= lolo. Page 7. 3D SIMULATIONS OF NATURAL CONVECTION 863 ...