Drying (Consolidation) Porous Ceramic by Considering the Microscopic Pore Temperature Gradient

2011 ◽  
Vol 147 ◽  
pp. 210-214 ◽  
Author(s):  
Zawati Harun ◽  
David Gethin
Keyword(s):  
Mass Transfer ◽  
Temperature Gradient ◽  
Porous Ceramic ◽  
Convective Drying ◽  
Comprehensive Model ◽  
Two Dimensional ◽  
Drying Process ◽  
Governing Equations ◽  
Fully Coupled ◽  
Good Agreement

In this work, a two-dimensional numerical model of heat and mass transfer for the convective drying process of ceramic material was developed. The governing equations of fully coupled non-linear partial differential was derived from the most comprehensive model with considering the heat, moisture and gas transport along with the influence of microscopic pore temperature gradient. Through validation the distribution of the measured variables and coefficients (diffusivity) show a good agreement with the drying stage in porous material.

Quality Assessment and Mathematical Modeling of Hot-Air Convective Drying of Persimmon (Diospyros kaki L.) Fruit

2017 ◽  
Vol 13 (7) ◽  
Author(s):  
Claudia Giovagnoli-Vicuña ◽  
Nelson O. Moraga ◽  
Vilbett Briones-Labarca ◽  
Pablo Pacheco-Pérez
Keyword(s):  
Quality Parameters ◽  
Time Function ◽  
Convective Drying ◽  
Diospyros Kaki ◽  
Drying Process ◽  
Temperature Function ◽  
Persimmon Fruit ◽  
Hot Air ◽  
Volume Method ◽  
Good Agreement

Abstract The influence of drying on the color, porosity, shrinkage and moisture of persimmon fruit during convective drying was determined by computer vision. The experiments were performed with persimmon fruit that were cut into slab 20 × 20 mm, which were arranged into a bigger slab, 60 × 60 mm. Drying process was carried out at 60 °C. Noticeable changes in quality parameters (color, porosity and shrinkage) could be observed during the drying process, where the central region of the sample evidenced less changes. Persimmon’s physical properties were experimentally obtained as the temperature function and heat and mass convective coefficients were adjusted as a time function. A numerical simulation using the Finite Volume Method allowed to describe the evolution of temperature and moisture content distributions during drying. The numerical and experimental results of temperature and moisture during persimmon drying were found to be in a good agreement.

Heat and Mass Transfer during Drying of Clay Ceramic Materials: A Three-Dimensional Analytical Study

2017 ◽  
Vol 10 ◽  
pp. 93-106 ◽  
Author(s):  
M.K. Teixeira de Brito ◽  
D.B. Teixeira de Almeida ◽  
A.G. Barbosa de Lima ◽  
L. Almeida Rocha ◽  
E. Santana de Lima ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Analytical Study ◽  
Separation Of Variables ◽  
Three Dimensional ◽  
Ceramic Materials ◽  
Governing Equations ◽  
Convective Boundary ◽  
Good Agreement

This work aims to study heat and mass transfer in solids with parallelepiped shape with particular reference to drying process. A transient three-dimensional mathematical model based on the Fick ́s and Fourier ́s Laws was developed to predict heat and mass transport in solids considering constant physical properties and convective boundary conditions at the surface of the solid. The analytical solution of the governing equations was obtained using the method of separation of variables. The study was applied in the drying of common ceramic bricks. Predicted results of the heating and drying kinetics and the moisture and temperature distributions inside the material during the process, are compared with experimental data and good agreement was obtained. It has been found that the vertices of the solid dry and heat first. This provokes thermal and hydric stresses inside the material, which may compromise the quality of the product after drying.

Thermodynamic Theory of Convective Drying Process of Porous Media

2002 ◽  
Author(s):  
You-Rong Li ◽  
Dan-Ling Zeng
Keyword(s):  
Mass Transfer ◽  
Heat Source ◽  
Heat And Mass Transfer ◽  
Internal Heat ◽  
Internal Heat Source ◽  
Thermodynamic Theory ◽  
Convective Drying ◽  
Internal Mass ◽  
Drying Process ◽  
Mass Source

Based on non-equilibrium thermodynamic theory and combined with the conservation laws, a comprehensive theoretical model was established to describe heat and mass transfer during convective drying process, and numerical calculation was performed. The results show that: (a) the external convective heat and mass transfer may be treated as the conductive heat transfer with internal heat source and the molecular mass diffusion with internal mass source, respectively, and the ability of heat and mass transfer mainly depends on the strength of the heat source and mass source; the higher the temperature of the drying media, the lower the strength of the internal heat source, but the higher that of the internal mass sources; (b) the evaporation of internal water takes place inside the whole material, and the molecular mass diffusion of the internal vapor is in the direction of decreasing mass transfer potential, not along the decreasing partial pressure of vapor.

scholarly journals 3D simulation on convective drying process for cylindrical tea particle using CFD software to analyze the heat and mass transfer phenomena

2020 ◽  
Author(s):  
Eflita Yohana ◽  
Nazaruddin Sinaga ◽  
Haryo Pachusadewo ◽  
M. Irfan Nugraha ◽  
M. Endy Yulianto ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
3D Simulation ◽  
Convective Drying ◽  
Drying Process

scholarly journals A modification of the CABARET scheme for numerical simulation of multicomponent gaseous flows in two-dimensional domains

2015 ◽  
pp. 436-445
Author(s):  
А.В. Данилин ◽  
А.В. Соловьев ◽  
А.М. Зайцев
Keyword(s):  
Numerical Simulation ◽  
Initial Conditions ◽  
Experimental Studies ◽  
Two Dimensional ◽  
Governing Equations ◽  
Cabaret Scheme ◽  
Gaseous Flows ◽  
Multicomponent Gas ◽  
Good Agreement ◽  
Made In

Предложен явный численный алгоритм для расчета течений смесей идеальных газов в двумерных областях. Приведены физическая модель и уравнения движения смеси в консервативной и характеристической формах. Дискретизация уравнений движения произведена по методике Кабаре. Алгоритм испытан на задачах о прохождении ударной волны в воздухе через неоднородности из легкого и тяжелого газов, начальные условия для которых адаптированы из рассмотренных другими авторами натурных и численных экспериментов. Показано хорошее совпадение расчетов по предложенному алгоритму с результатами этих экспериментов. An explicit numerical algorithm for calculation of two-dimensional motion of multicomponent gas mixtures is proposed. A physical model as well as conservative and characteristic forms of governing equations are given. The discretization of the governing equations is made in accordance with the CABARET (Compact Accurately Boundary Adjusting-REsolution Technique) approach. The proposed algorithm is tested on problems of air shock waves passing through dense and dilute volume inhomogeneities with initial conditions adopted from numerical and experimental studies of other authors. A good agreement between the results of these studies and those obtained by the CABARET approach is shown.

scholarly journals RESEARCH OF HEAT AND MASS TRANSFER DURING CONVECTIVE DRYING OF COLLOID CAPILLARY-POROUS MATERIALS

2020 ◽  
Author(s):  
Kateryna Slobodianiuk ◽  
◽  
Kateryna Samoilenko ◽  
Keyword(s):  
Mass Transfer ◽  
Porous Materials ◽  
Heat And Mass Transfer ◽  
Raw Materials ◽  
Biochemical Properties ◽  
The Body ◽  
Biologically Active ◽  
Convective Drying ◽  
Drying Process ◽  
Vegetable Raw Materials

The article presents a reasonable analysis and relevance of the study of the drying process of vegetable raw materials (colloidal capillary-porous materials). Drying is an energy-intensive industrial process that is defined from a technological point of view: on the one hand by heat and moisture exchange between the body surface and the environment, on the other hand by heating the body and transferring moisture inside it due to the form of moisture. One of the most effective ways to increase the shelf life of food is to dry it to equilibrium humidity. Very important are the technological parameters of the drying regimes, which, when used rationally, are able to preserve the biochemical properties and nutrients of the raw material at a high level in the obtained dry product. The study of dehydration of vegetable raw materials is widely practiced around the world, especially in countries such as Germany, France, USA, Argentina, Hungary, Brazil, Poland, Korea, China, Malaysia. However, the obtained processed products lose their biologically active components and nutrients, and the processing process is energy consuming. Therefore, the problem is relevant and needs an effective solution. In this paper, the kinetics of the drying process, thermogravimetric studies and a mathematical model for colloidal capillary-porous materials of plant origin were analyzed. According to the results of the highlighted research, the process of convective drying of colloidal capillary-porous materials was intensified above 21% due to the use of innovative step regimes. The developed beet-rhubarb composition is a colloidal capillary-porous material that stabilizes and protects at the biochemical level betanin of the beet from the effects of temperature during convective drying, has in comparison with the components of the composition lower heat of dehydration and increased thermal-stability. Prolonged high-temperature exposure causes instant complete destruction of sugars, proteins and other nutrients components. Derivatographic studies have confirmed that the use of the temperature range of 100 ° C in a stepwise mode of 100/60 ° C for the developed soybean-spinach composition is safe for biologically active substances and it is justified by experimental temperature curves. Numerical modeling of heat and mass transfer during convective drying of crushed beets and crushed soybeans using the known model by A.V. Lykov satisfactorily describes the process and can be used to model the convection drying of colloidal capillary-porous materials.

Analysis of Mass Transfer during Loose Material’s Convective Drying

2011 ◽  
Vol 317-319 ◽  
pp. 2018-2021
Author(s):  
Xue Ping Wang ◽  
Wei Wei Cao ◽  
Yong Song ◽  
Zhen Wei Zhang
Keyword(s):  
Mass Transfer ◽  
Moisture Transfer ◽  
Convective Drying ◽  
Drying Rate ◽  
Drying Process ◽  
Moisture Migration ◽  
Phenomenological Equations ◽  
Heat And Moisture ◽  
The Mathematical Model ◽  
The Relationship

Abstract. The thesis focuses on how to get the mathematical model of mass transfer under some certain simplified conditions and how to gain the moisture content of materials under drying. In this process, authors utilized phenomenological equations of heat and moisture transfer and analyzed the relationship and cross effects between force and flow, which were about various kinds of heat and mass transfer. In addition, the authors also used computer simulation in drying process. The result of the study is that drying rate depends on the speed of the internal moisture migration. The conclusions of this thesis have great significance for selecting the dryer and in the actual production.

scholarly journals Kazantsev model in non-helical 2.5-dimensional flows

2016 ◽  
Vol 806 ◽  
pp. 627-648 ◽  
Author(s):  
K. Seshasayanan ◽  
A. Alexakis
Keyword(s):  
Turbulent Flows ◽  
Three Dimensional ◽  
Analytical Calculation ◽  
Reynolds Numbers ◽  
Two Dimensions ◽  
Two Dimensional ◽  
Control Parameters ◽  
Governing Equations ◽  
Field Correlation ◽  
Good Agreement

We study the dynamo instability for a Kazantsev–Kraichnan flow with three velocity components that depend only on two dimensions $\boldsymbol{u}=(u(x,y,t),v(x,y,t),w(x,y,t))$ often referred to as 2.5-dimensional (2.5-D) flow. Within the Kazantsev–Kraichnan framework we derive the governing equations for the second-order magnetic field correlation function and examine the growth rate of the dynamo instability as a function of the control parameters of the system. In particular we investigate the dynamo behaviour for large magnetic Reynolds numbers $Rm$ and flows close to being two-dimensional and show that these two limiting procedures do not commute. The energy spectra of the unstable modes are derived analytically and lead to power-law behaviour that differs from the three-dimensional and two-dimensional cases. The results of our analytical calculation are compared with the results of numerical simulations of dynamos driven by prescribed fluctuating flows as well as freely evolving turbulent flows, showing good agreement.

Analytical Study of Heat and Mass Transfer in Porous Sheets During Contact Drying Process

2008 ◽  
Author(s):  
Mohammad R. Izadpanah ◽  
Amir R. Ansari Dezfooli
Keyword(s):  
Mass Transfer ◽  
Temperature Distribution ◽  
Moisture Content ◽  
Close Agreement ◽  
Analytical Study ◽  
Numerical Data ◽  
Drying Process ◽  
Governing Equations ◽  
Sturm Liouville ◽  
Contact Drying

Contact drying process has gained wide application in different industries including paper, ceramics and construction industries. Suitable control over temperature distribution will result in required moisture content and its distribution. In the present study, governing equations for a porous sheet are derived using Luikov equation. These equations are then converted into sturm-liouville equations and solved simultaneously. Comparison of temperature and moisture distributions with numerical data shows a close agreement.

scholarly journals NUMERICAL RESEARCH OF THE CHANGE OF REGIME FOR UNSTABLE MASS TRANSFER IN A TERNARY GAS MIXTURE HYDROGEN- NITRIC OXIDE-NITROGEN

2020 ◽  
Vol 72 (4) ◽  
pp. 112-116
Author(s):  
A.B. Kalimov ◽  
◽  
O.V. Fedorenko ◽  
V.N. Kossov ◽  
◽  
...  
Keyword(s):  
Mass Transfer ◽  
Finite Size ◽  
Pressure Change ◽  
Gas Mixture ◽  
Governing Equations ◽  
Diffusion Channel ◽  
Numerical Research ◽  
Pressure Changes ◽  
Matter Transfer ◽  
Good Agreement

On the basis of the software package "MathCad", by solving the Stefan-Maxwell diffusion equations, the evolution of the features of mass transfer in a three-component gas mixture, depending on pressure changes, has been numerically studied. In this analysis, the mixing process is studied in a vertical cylindrical channel of a finite size and at the isothermal conditions. The governing equations are solved at the boundary conditions assuming the absence of matter transfer through the walls of diffusion channel. Through the Rayleigh partial numbers, the influence of the pressure change on the behaviour of diffusion and convective flows is examined. The numerical results reveal that an increase in the pressure leads to a change of modes in ternary gas mixture. The present results are in good agreement with the existing experimental data.

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