scholarly journals New insight into the Fourier-like and Darcy-like models in porous medium

2020 ◽  
Vol 24 (6 Part A) ◽  
pp. 3847-3858
Author(s):  
Xiao-Jun Yang
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Transfer Process ◽  
Scaling Law ◽  
Heat Transfer Process ◽  
Fractal Scaling ◽  
Special Cases ◽  
General Calculus ◽  
Insight Into

In this study, we propose the general calculus operators based on the Richardson scaling law and Korcak scaling law. The Richardson-scaling-law calculus is considered to investigate the Fourier-like law for the scaling-law flow of the heat in the heat-transfer process. The Korcak-scaling-law calculus is used to model the Darcy-like law for describing the scaling-law flow of the fluid in porous medium. The formulas are as the special cases of the topology calculus proposed for descriptions of the fractal scaling-law behaviors in nature phenomena.

Oscillatory heat transfer process in a vertical strip immersed in a porous medium

2004 ◽  
Vol 40 (12) ◽  
pp. 937-942 ◽  
Author(s):  
I. Contreras ◽  
C. Trevi�o ◽  
J. C. Prince
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Transfer Process ◽  
Heat Transfer Process ◽  
Vertical Strip

Simultaneous Wicking-Convection Heat Transfer Process with Non-Newtonian Power-Law Fluid

2010 ◽  
Vol 297-301 ◽  
pp. 117-125
Author(s):  
Oscar Bautista ◽  
Federico Méndez ◽  
Eric Bautista
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Newtonian Fluid ◽  
Power Law ◽  
Transfer Process ◽  
Numerical Solutions ◽  
Heat Transfer Process ◽  
Dimensionless Temperature ◽  
Power Law Fluid ◽  
Temperature And Pressure

In this work, we have theoretically analyzed the heat convection process in a porous medium under the influence of spontaneous wicking of a non-Newtonian power-law fluid, trapped in a capillary element, considering the presence of a temperature gradient. The capillary element is represented by a porous medium which is initially found at temperature and pressure . Suddenly the lower part of the porous medium touches a reservoir with a non-Newtonian fluid with temperature and pressure . This contact between both phases, in turn causes spontaneously the wicking process. Using a one-dimensional formulation of the average conservation laws, we derive the corresponding nondimensional momentum and energy equations. The numerical solutions permit us to evaluate the position and velocity of the imbibitions front as well as the dimensionless temperature profiles and Nusselt number. The above results are shown by considering the physical influence of two nondimensional parameters: the ratio of the characteristic thermal time to the characteristic wicking time, , the ratio of the hydrostatic head of the imbibed fluid to the characteristic pressure difference between the wicking front and the dry zone of the porous medium, , and the power-law index, n, for the non-Newtonian fluid. The predictions show that the wicking and heat transfer process are strongly dependent on the above nondimensional parameters, indicating a clear deviation in comparison with and n = 1, that represents the classical Lucas-Washburn solution.

scholarly journals Modeling of heat transfer in an element with anisotropic porosity

2021 ◽  
Vol 2039 (1) ◽  
pp. 012011
Author(s):  
N N Kozhukhov ◽  
E A Kozhukhova ◽  
D A Konovalov ◽  
D A Prutskikh ◽  
V I Perunova
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Porous Structure ◽  
Transfer Process ◽  
Heat Transfer Process ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Porosity Changes

Abstract The paper presents the results of modeling the heat transfer process in a channel filled with a porous medium. Moreover, the porosity changes according to the specified law along one of the coordinates. It is shown that an element with anisotropic porosity has better heat transfer characteristics in comparison with an element with a homogeneous porous structure.

Design of the Blast Furnace Wall Structure Made of Efficient Materials. Part 4. Calculation Examples

2020 ◽  
Vol 786 (11) ◽  
pp. 30-34
Author(s):  
A.M. IBRAGIMOV ◽  
◽  
L.Yu. GNEDINA ◽  
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Blast Furnace ◽  
Boundary Value Problems ◽  
Transfer Process ◽  
Rational Design ◽  
Boundary Value ◽  
Heat Transfer Process ◽  
Furnace Wall ◽  
Time Interval

This work is part of a series of articles under the general title The structural design of the blast furnace wall from efficient materials [1–3]. In part 1, Problem statement and calculation prerequisites, typical multilayer enclosing structures of a blast furnace are considered. The layers that make up these structures are described. The main attention is paid to the lining layer. The process of iron smelting and temperature conditions in the characteristic layers of the internal environment of the furnace is briefly described. Based on the theory of A.V. Lykov, the initial equations describing the interrelated transfer of heat and mass in a solid are analyzed in relation to the task – an adequate description of the processes for the purpose of further rational design of the multilayer enclosing structure of the blast furnace. A priori the enclosing structure is considered from a mathematical point of view as the unlimited plate. In part 2, Solving boundary value problems of heat transfer, boundary value problems of heat transfer in individual layers of a structure with different boundary conditions are considered, their solutions, which are basic when developing a mathematical model of a non-stationary heat transfer process in a multi-layer enclosing structure, are given. Part 3 presents a mathematical model of the heat transfer process in the enclosing structure and an algorithm for its implementation. The proposed mathematical model makes it possible to solve a large number of problems. Part 4 presents a number of examples of calculating the heat transfer process in a multilayer blast furnace enclosing structure. The results obtained correlate with the results obtained by other authors, this makes it possible to conclude that the new mathematical model is suitable for solving the problem of rational design of the enclosing structure, as well as to simulate situations that occur at any time interval of operation of the blast furnace enclosure.

Numerical Simulation for Microconvection Around Nano-Particle With Brownian Motion in Liquid

2003 ◽  
Author(s):  
B. X. Wang ◽  
H. Li ◽  
X. F. Peng ◽  
L. X. Yang
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Brownian Motion ◽  
Numerical Model ◽  
Temperature Gradient ◽  
Transfer Process ◽  
Heat Transfer Process ◽  
Nano Particles ◽  
Analytic Method ◽  
Nano Particle

The development of a numerical model for analyzing the effect of the nano-particles’ Brownian motion on the heat transfer is described. By using the Maxwell velocity distribution relations to calculate the most possible velocity of fluid molecules at certain temperature gradient location around the nano-particle, the interaction between fluid molecules and one single nano-particle is analyzed and calculated. Based on this, a syntonic system is proposed and the coupled effect that Brownian motion of nano-particles has on fluid molecules is simulated. This is used to formulate a reasonable analytic method, facilitating laboratory study. The results provide the essential features of the heat transfer process, contributed by micro-convection to be considered.

The 3-D Numerical Simulation of Heat Transfer Process of Finned Copper Tube

2011 ◽  
Vol 393-395 ◽  
pp. 412-415
Author(s):  
Jian Hua Zhong ◽  
Li Ming Jiang ◽  
Kai Feng
Keyword(s):  
Heat Transfer ◽  
Transfer Process ◽  
Theoretical Calculations ◽  
Structural Parameters ◽  
Convection Heat Transfer ◽  
Heat Transfer Process ◽  
Finned Tube ◽  
Copper Tube ◽  
Central Air Conditioning ◽  
Fin Thickness

In this article, finned copper tube used in the central air conditioning was acted as the discussed object. According to the combination with actual processing and theoretical calculations, Five finned tube was selected with typical structural parameters, and established their entity model using Pro/E, then the heat transfer process of finned tube was simulated through the ANSYS, the effect of the fin height, fin thickness and other structure parameters to the heat transfer enhancement of finned tube was researched. Meantime the efficiency of the heat transfer under different convection heat transfer coefficient was also studied.

Numerical Study on the Effect of Inner Tube Position on Heat Transfer Process in Self-Recuperative Radiant Tube

2011 ◽  
Vol 228-229 ◽  
pp. 676-680 ◽  
Author(s):  
Ye Tian ◽  
Xun Liang Liu ◽  
Zhi Wen
Keyword(s):  
Heat Transfer ◽  
Transfer Process ◽  
Numerical Study ◽  
Flame Temperature ◽  
Three Dimensional ◽  
Mathematic Model ◽  
Heat Transfer Process ◽  
Bulk Temperature ◽  
Radiant Tube ◽  
Peak Value

A three-dimensional mathematic model is developed for a 100kw single-end recuperative radiant tube and the simulation is performed with the CFD software FLUENT. Also it is used to investigate the effect of distance between combustion chamber exit and inner tube on heat transfer process. The results suggest that the peak value of combustion flame temperature drops along with the increasing of distance, which leads to low NOX discharging. Also radiant tube surface bulk temperature decreases, which causes radiant tube heating performance losses.

Study the Heat Transfer Process From Electron-Phonon Nonequilibrium in Thin Gold Film to Glass Substrate Through Transient Thermoreflectance Measurements

2010 ◽  
Author(s):  
Weigang Ma ◽  
Haidong Wang ◽  
Xing Zhang ◽  
Wei Wang
Keyword(s):  
Heat Transfer ◽  
Transfer Process ◽  
Borosilicate Glass ◽  
Glass Substrate ◽  
Physical Vapor Deposition ◽  
Gold Film ◽  
Coupling Factor ◽  
Heat Transfer Process ◽  
Thin Gold Film ◽  
Open Question

How the energy transfers during electron-phonon nonequilibrium in thin metal films is still an open question, and how to measure the intrinsic thermal transport properties of the material under the covering layer is another challenge. In this paper, the heat transfer process from electron-phonon nonequilibrium in thin gold film to borosilicate glass substrate has been studied by resorting to different segments of the transient thermoreflectance signal, which is obtained from the rear-pump front-probe transient thermoreflectance technique. The gold film, which has a thickness of 23.1 nm, is deposited on the borosilicate glass substrate using using a physical vapor deposition (PVD) approach. Within the framework of the two-temperature model (TTM), the electron-phonon (e-ph) coupling factors of the gold film, which reflect the strength of heat flow from hot electrons to cold phonons, are derived from the signal taken after the first several picoseconds with different pump fluences, and the measured value is (1.95–2.05)×1016 W m−3 K−1. The electron-phonon coupling factor does not significantly change in response to the pump pulse fluence variation and exhibits little change compared to the bulk gold value 2.4×1016 W m−3 K−1. Furthermore, the thermal conductivity of the glass substrate is obtained through the thermoreflectance signal between 20 to 140 picoseconds and the value is W m−1 K−1.

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