scholarly journals HEAT EXCHANGE OF ELECTRIC CONDUCTIVE LIQUID AT LARGE VALUES OF THE REYNOLD'S MAGNETIC NUMBER

2021 ◽  
pp. 12-22
Author(s):  
С.В. Соловьев ◽  
Т.С. Соловьева
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Reynolds Number ◽  
Fluid Flow ◽  
Heat Exchange ◽  
Spherical Layer ◽  
Magnetic Reynolds Number ◽  
Electrically Conductive ◽  
Conductive Liquid ◽  
Nusselt Numbers

Представлены результаты численного моделирования нестационарного конвективного теплообмена и магнитной гидродинамики электропроводной жидкости в сферическом слое при граничных условиях для температуры первого рода. Исследовано влияние величины магнитного числа Рейнольдса на эволюцию структуры течения жидкости, поле температуры, магнитной индукции и распределение чисел Нуссельта. The results of numerical simulation of unsteady convective heat transfer and magneto hydrodynamics of an electrically conductive fluid in a spherical layer under boundary conditions for a temperature of the first kind are presented. The influence of the value of the magnetic Reynolds number on the evolution of the structure of the fluid flow, the field of temperature, magnetic induction and the distribution of Nusselt numbers is investigated.

scholarly journals HEAT EXCHANGE OF ELECTRIC CONDUCTIVE LIQUID WHEN DEPLOYING THE HEAT FROM THE INNER SURFACE OF THE SPHERICAL LAYER AT SMALL VALUES OF THE REYNOLD'S MAGNETIC NUMBER

2021 ◽  
pp. 212-219
Author(s):  
С.В. Соловьев
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Reynolds Number ◽  
Spherical Layer ◽  
Magnetic Reynolds Number ◽  
Unsteady Heat Transfer ◽  
Electrically Conductive ◽  
Conductive Liquid ◽  
Nusselt Numbers ◽  
Inner Surface

Представлены результаты численного моделирования нестационарного теплообмена и магнитной гидродинамики электропроводной жидкости в сферическом слое. Исследовано влияние малых значений магнитного числа Рейнольдса и диссипации джоулевой теплоты на эволюцию структуры течения жидкости, поле температуры, магнитной индукции и распределение чисел Нуссельта. The results of numerical simulation of unsteady heat transfer and magneto hydrodynamics of an electrically conductive fluid in a spherical layer are presented. The influence of small values ​​of the magnetic Reynolds number and dissipation of Joule heat on the evolution of the structure of the fluid flow, the field of temperature, magnetic induction and the distribution of Nusselt numbers is investigated.

scholarly journals HEAT EXCHANGE OF ELECTRIC CONDUCTIVE LIQUID IN THE SUPPLY OF HEAT TO THE INNER SURFACE OF THE SPHERICAL LAYER AT SMALL VALUES OF THE REYNOLD'S MAGNETIC NUMBER

2021 ◽  
pp. 35-42
Author(s):  
С.В. Соловьев
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Spherical Layer ◽  
Magnetic Reynolds Number ◽  
Joule Dissipation ◽  
Unsteady Heat Transfer ◽  
Electrically Conductive ◽  
Conductive Liquid ◽  
Nusselt Numbers ◽  
Inner Surface

Представлены результаты численного моделирования нестационарного теплообмена и магнитной гидродинамики электропроводной жидкости в сферическом слое. Исследовано влияние малых значений магнитного числа Рейнольдса и теплоты джоулевой диссипации на эволюцию структуры течения жидкости, поле температуры, магнитной индукции и распределение чисел Нуссельта. The results of numerical simulation of unsteady heat transfer and magneto hydrodynamics of an electrically conductive fluid in a spherical layer are presented. The influence of small values of the magnetic Reynolds number and the heat of Joule dissipation on the evolution of the structure of the fluid flow, the field of temperature, magnetic induction and the distribution of Nusselt numbers is investigated.

Simulation of electrically conductive liquid convection in a spherical layer when heat is applied to the inner sphere

2019 ◽  
Author(s):  
С.В. Соловьев
Keyword(s):  
Heat Transfer ◽  
Heat Exchange ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Magnetic Induction ◽  
Spherical Layer ◽  
Gravity Vector ◽  
Joule Dissipation ◽  
Conductive Liquid ◽  
Nusselt Numbers

Представлены результаты численного моделирования конвективного теплообмена электропроводящей жидкости между концентрическими сферами при подводе тепла к внутренней сфере. Исследовано влияние числа Грасгофа и джоулевой диссипации на структуру течения жидкости, поля температуры, магнитной индукции и распределение локальных чисел Нуссельта. Получено уравнение подобия теплообмена, когда ускорение свободного падения направлено к центру сферического слоя. The Boussinesq approximation is used for modelling a large class of problems of convective heat transfer in spherical concentric layers in which the gravity vector is directed vertically downwards. But for problems of geophysics and astrophysics there is a fundamental difference, the gravity vector is directed along the radius to the center of the spherical layer. Therefore, the study of convective heat transfer in spherical layers, when the vector of gravitational acceleration is directed along the radius to the center of the spherical layer, is of independent interest. In this paper, the influence of the Grashof number, the Joule dissipation heat on the fluid flow structure, temperature field, magnetic induction, and the distribution of Nusselt numbers when heat is applied from below are studied. To solve the problem, the finite element method is used. In a dimensionless formulation, the problem is solved taking into account both the heat of the Joule dissipation, magnetic, inertial, viscous and lifting forces in a spherical coordinate system and the symmetry in longitude. The stationary fields of temperature, stream functions, vortex strength, radial and meridional components of magnetic induction and the distribution of local Nusselt numbers of electro conductive liquid in a concentric spherical layer for different Grashof numbers with and without accounting for the heat of Joule dissipation are obtained when heat is applied to the inner sphere. Two critical values of the Grashof number are numerically determined. The equation of heat exchange similarity is obtained, when the acceleration of gravity is directed to the center of the spherical layer. The mathematical model and the presented results may be useful for the study of convective heat exchange of electrically conducting fluid in space technologies and in the geophysical and astrophysical problems.

Numerical Simulation of Heat and Flow of Liquid Through Minichannels

2006 ◽  
Author(s):  
Heming Yun ◽  
Lin Cheng ◽  
Liqiu Wang ◽  
Shusheng Zhang
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Reynolds Number ◽  
Aspect Ratio ◽  
Flow Region ◽  
Resistance Coefficient ◽  
Equivalent Diameter ◽  
Nusselt Numbers ◽  
Friction Factors ◽  
Simulation Results

In this paper the heat transfer and flow in minichannels was investigated by using CFD methods. The numerical simulation results show that the equivalent diameter has little influence on resistance coefficient in the laminar region. In the turbulent flow region, the resistance coefficient decreases with the increasing of the equivalent diameter. In all computation region, the friction factors increases with increasing of the aspect ratio, and the friction factors decreases obviously with increasing of Reynolds number. The numerical simulation results show that the equivalent diameter has little influence on heat transfer Nusselt number in laminar flow region. In turbulent region, the Nusselt numbers are larger than those in macro channels. The Nusselt numbers increase with decreasing of equivalent diameter and the aspect ratio for a given Reynolds number.

Numerical Simulation of Liquefied Natural Gas in Rib-Tube

2013 ◽  
Vol 483 ◽  
pp. 162-165
Author(s):  
Su Hou De ◽  
Zhang Yu Fu ◽  
Ji Yong Che ◽  
Xiao Long Wen
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Fluid Flow ◽  
Heat Exchange ◽  
Natural Gas ◽  
Liquefied Natural Gas ◽  
Dispersed Phase ◽  
Wall Function ◽  
Governing Equations ◽  
Set Up

The flow of liquefied natural gas (LNG) which was coupled between heat transfer and fluid-flow in rib-tube was studied in this paper. Based on theoretical analysis, the model and wall-function were chosen to simulate the flow field of rib-tube, and the multiphase flow was described by the mixture model, in which the dispersed phase was defined by different velocity. In addtion, self-defining functions were used and governing equations were set up to solve the dispersed phase, and the result were compared with the experiment. The process of fluid-flow and heat exchange on rib-tube was simulated, and the contours of temperature, pressure, velocity, gas fraction were obtained, which showed that, the parameters of above changed when the temperature was rising and the LNG evaporating along the rib-tube, and a mixed process existed in the middle of the heat tube.

Numerical Simulation and Optimization of Heat Transfer in Microchannel by Implementing Nonuniform Electrokinetic Forces

2008 ◽  
Author(s):  
V. Esfahanian ◽  
F. Kowsary ◽  
N. Noroozi ◽  
M. Rezaei Barmi
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Reynolds Number ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Flux Boundary Condition ◽  
Simulation And Optimization ◽  
Nusselt Numbers ◽  
Wall Potential ◽  
Uniform Wall

The increasing power dissipation and decreasing dimensions of microelectronic devices have emphasized the demand for extremely efficient compact cooling technology. Microchannel heat sinks are of particular interest due to high rates of heat transfer, which have become known as one of the effective cooling technologies. In the present work, numerical simulation of incompressible flow in two dimensional microchannels by implementing nonuniform electrokinetic forces is performed using finite volume method. The velocity field and the heat transfer rate are influenced by the wall potential variations through the microchannel. Nondimensional parameters of heat transfer and fluid flows, Debay Huckel length, microchannel size and wall charge potential distribution, have major roles in this investigation. For fixed values of Reynolds number and microchannel size, the patterns of wall potentials are optimized to enhance the heat transfer rate. Velocity profiles are computed and temperature distribution and Nusselt number are obtained for uniform wall heat flux boundary condition. Average and local Nusselt numbers are illustrated for different wall potential configurations and Reynolds number. Velocity vectors and pressure drop are presented for different zeta potentials and Reynolds numbers. Finally, results of nonuniform electrical force are compared to uniform ones.

Analysis of Thermal Creep Effects on Fluid Flow and Heat Transfer in a Microchannel Gas Heating

2021 ◽  
Vol 13 (6) ◽  
Author(s):  
K. M. Ramadan ◽  
Mohammed Kamil ◽  
I. Tlili ◽  
O. Qisieh
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Fluid Flow ◽  
Heat Exchange ◽  
Channel Wall ◽  
Stokes Equations ◽  
Thermal Creep ◽  
Flow And Heat Transfer ◽  
Creep Effect ◽  
Gas Heating

Abstract Thermal creep effects on fluid flow and heat transfer in a microchannel gas flow at low velocities are studied numerically. The continuity and Navier–Stokes equations in vorticity–stream function form, coupled with the energy equation, are solved, considering the thermal creep effect due to the longitudinal temperature gradient along the channel wall in addition to the combined effects of viscous dissipation, pressure work, axial conduction, shear work, and nonequilibrium conditions at the gas–wall interface. The governing equations are also solved without thermal creep, and comparisons between the two solutions are presented to evaluate the thermal creep effect on the flow field in the slip flow regime at relatively low Reynolds numbers. The results presented show that the thermal creep effect on both velocity and temperature fields become more significant as the Reynolds number decreases. Thermal creep effect on the velocity field also extends a longer distance downstream the channel as the Reynolds number decreases, hence increasing the hydrodynamics entrance length. Thermal creep can cause high positive velocity gradients at the upper channel wall for gas heating and hence reverse the flow rotation in the fluid layers adjacent to the wall. Thermal creep also results in a higher gas temperature in the developing region and higher heat exchange between the fluid and the channel wall in the entrance region. Thermal creep effect on heat exchange between the gas and the channel wall becomes more significant as the Knudsen number decreases.

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