On the Modeling of Drying Process in an Industrial Tunnel Dryer

2020 ◽  
Vol 400 ◽  
pp. 51-56
Author(s):  
Francisca Valdeiza de Souza Tavares ◽  
Atacy Maciel de Melo Cavalcante ◽  
Maria José de Figueiredo ◽  
Anderson Ferreira Vilela ◽  
Ana Raquel Carmo de Lima ◽  
...  
Keyword(s):  
Moisture Content ◽  
Mass Conservation ◽  
Convective Drying ◽  
Average Moisture Content ◽  
Drying Process ◽  
Governing Equations ◽  
Tunnel Dryer ◽  
Good Concordance ◽  
Volume Method ◽  
Hollow Bricks

This paper aims to study convective drying of industrial hollow bricks in a tunnel dryer. A transient mathematical model based on the heat and mass conservation equations applied to the air and brick was derived and the numerical solution (finite-volume method) of the governing equations is presented. Predicted and experimental data of the average moisture content and the temperature of the product during the drying process are compared and a good concordance was verified. Numerical results inside the bed confirm an almost null difference between the moisture content along the process. Similar behavior was verified to the product temperature. These results confirm an efficient drying process.

Heat and Mass Diffusion Including Shrinkage and Hygrothermal Stress during Drying of Holed Ceramics Bricks

2011 ◽  
Vol 312-315 ◽  
pp. 971-976 ◽  
Author(s):  
J. Barbosa da Silva ◽  
G. Silva Almeida ◽  
W.C.P. Barbosa de Lima ◽  
Gelmires Araújo Neves ◽  
Antônio Gilson Barbosa de Lima
Keyword(s):  
Moisture Content ◽  
Three Dimensional ◽  
Average Moisture Content ◽  
Stress Distributions ◽  
Drying Process ◽  
Convective Boundary ◽  
Volume Method ◽  
Hygrothermal Stress ◽  
Thermo Physical Properties ◽  
Good Agreement

The Aim of this Work Is to Present a Three-Dimensional Mathematical Modelling to Predict Heat and Mass Transport inside the Industrial Brick with Rectangular Holes during the Drying Including Shrinkage and Hygrothermalelastic Stress Analysis. the Numerical Solution of the Diffusion Equation, Being Used the Finite-Volume Method, Considering Constant Thermo-Physical Properties and Convective Boundary Conditions at the Surface of the Solid, it Is Presented and Analyzed. Results of the Temperature, Moisture Content and Stress Distributions, and Drying and Heating Kinetics Are Shown and Analyzed. Results of the Average Moisture Content and Surface Temperature of the Brick along the Drying Process Are Compared with Experimental Data (T = 80.0oC and RH = 4.6 %) and Good Agreement Was Obtained. it Was Verified that the Largest Temperature, Moisture Content and Stress Gradients Are Located in the Intern and External Vertexes of the Brick.

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.

scholarly journals A Framework and Numerical Solution of the Drying Process in Porous Media by Using a Continuous Model

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Hong Thai Vu ◽  
Evangelos Tsotsas
Keyword(s):  
Porous Media ◽  
Control Volume ◽  
Continuous Model ◽  
Control Volume Method ◽  
Drying Process ◽  
Transport Parameters ◽  
Governing Equations ◽  
Numerical Tools ◽  
Volume Method ◽  
The Continuum

The modelling and numerical simulation of the drying process in porous media are discussed in this work with the objective of presenting the drying problem as the system of governing equations, which is ready to be solved by many of the now widely available control-volume-based numerical tools. By reviewing the connection between the transport equations at the pore level and their up-scaled ones at the continuum level and then by transforming these equations into a format that can be solved by the control volume method, we would like to present an easy-to-use framework for studying the drying process in porous media. In order to take into account the microstructure of porous media in the format of pore-size distribution, the concept of bundle of capillaries is used to derive the needed transport parameters. Some numerical examples are presented to demonstrate the use of the presented formulas.

scholarly journals Development and performance evaluation of a solar tunnel date dryer in Oman

2012 ◽  
Vol 17 ◽  
pp. 21
Author(s):  
Mohammad Ali Basunia ◽  
Hamid H. Al-Handali ◽  
Mohammed Issa Al-Belushi ◽  
Mohammad Shafiur Rahman ◽  
Osman Maghoub
Keyword(s):  
Moisture Content ◽  
Initial Moisture Content ◽  
Average Moisture Content ◽  
Air Velocity ◽  
Sun Drying ◽  
Tunnel Dryer ◽  
Moisture Content Level ◽  
Collector Region ◽  
And Performance

Taking into consideration the date harvesting and landholding capacities of the marginalized rural farmers in Oman, a 12 meter long and 2 meter wide tunnel was designed and constructed to dry about 180-200 kg of freshly harvested dates per batch. Half of the tunnel base was used as a flat plate air heating solar collector and the other half as a dryer. The drying air was forced from the collector region (South side) to the drying region (North side) of the half circled tunnel where the product is to be dried. The drying temperature could be easily raised by some 5-30 oC above the ambient temperature inside the tunnel at an air velocity of approximately 0.5 m/sec. The test was conducted with 190.2 kg freshly harvested dates with initial moisture content of 32.8% (wet-basis) to analyze the performance of the dryer. The dates were dried to a final average moisture content of 18.6% (wet-basis) within two days (20 hours). The results indicated that the drying was faster in a solar tunnel dryer than the natural open air sun drying. It was possible to reach the moisture content level for safe storage within less than two days (20 hrs) with a solar tunnel dryer and 5-7 days in open air natural sun drying. The improvement in the quality of dates in terms of color and brightness was distinctly recognized. 

scholarly journals Mathematical description of super-high frequencies drying process of free-running food media in device with combined energy input

2020 ◽  
Vol 175 ◽  
pp. 05021
Author(s):  
Sergey Antipov ◽  
Andrey Klyuchnikov ◽  
Dmitry Kazartsev
Keyword(s):  
Moisture Content ◽  
Heat Input ◽  
High Frequency ◽  
Practical Interest ◽  
Optimal Solution ◽  
Food Products ◽  
Convective Drying ◽  
Drying Process ◽  
High Frequencies ◽  
Free Running

At the present time the maim quantity of free-running food products, including grains, are dried in units with convective method of heat input. To intensify convective drying, general attention is paid to improving the method of moving and mixing the product with drying agent, to guarantee fast and quality drying. The use of high and super-high frequency allows can significantly intensify the drying processes, because the phenomenon of super-high frequencies energy into heat conversion throughout the processed material volume contributes to the most uniform heating of the product, compared to other heat input methods. The optimal solution for drying free-running food products is a combination of convective and high-frequency heat input methods. This combination allows controlling gradients of moisture content and temperature, changing its directions, which significantly affects quality of the resulting dry product. In this regard, combined approach to drying process modeling is of practical interest: on the one hand, there are used analytical solutions, based on physical laws application or phenomenological equations, and, on the other hand, experimentally established a relationship between temperature and moisture content of media, which is considered as a heat and mass transfer characteristic for each material.

scholarly journals NUMERICAL AND EXPERIMENTAL STUDY OF A FREE INCOMPRESSIBLE ISOTHERMAL TURBULENT COAXIAL JET

2010 ◽  
Vol 9 (1-2) ◽  
pp. 98 ◽  
Author(s):  
G. R. Ströher ◽  
C. A. Martins ◽  
C. R. De Andrade
Keyword(s):  
Experimental Data ◽  
Turbulence Model ◽  
Velocity Ratio ◽  
Radial Profile ◽  
Mass Conservation ◽  
Experimental Measurements ◽  
Governing Equations ◽  
Self Similarity ◽  
Mean Velocity ◽  
Volume Method

In the present study the free incompressible isothermal turbulent coaxial jet problem is numerically solved, and compared with experimental measurements for different velocity ratio between the inner and the outer streams of the jet. The radial profile of the axial mean velocity was obtained with hot anemometry at different axial positions. Governing equations (mass conservation, momentum, turbulence model) were discretized employing the finite volume method with a segregated solver. The analysis of the experimental results showed that coaxial jet flow fields did not present self-similarity up to z/D=25, and the numerical solution using the Shih’s k ε turbulence model did not match reasonably with the experimental data, with a difference of about ± 10%.

Simulation of Drying Hevea brasiliensis Wood

2015 ◽  
Vol 1088 ◽  
pp. 802-806 ◽  
Author(s):  
Cláudio de Conti ◽  
Andrea Cressoni de Conti ◽  
Maristela Gava ◽  
Luiz Oliveira Veriano dalla Valentina ◽  
Glaucia Aparecida Prates
Keyword(s):  
Moisture Content ◽  
Statistical Method ◽  
Temperature Increase ◽  
Gravimetric Method ◽  
Average Moisture Content ◽  
Drying Process ◽  
Chi Square ◽  
Drying Time ◽  
Kiln Temperature ◽  
Drying Curve

The Simpson model proposes that the rate of wood drying is directly proportional to average moisture content. In this work was done the fitting and the reproduction of drying curve forHeveabrasiliensiswood through of Simpson model and the chi-square statistical method. The curves were obtained by drying 108 specimensHeveabrasiliensiswood with size 10 mm x 20 mm x 100 mm that were drying in a laboratory kiln. The drying control was performed through gradual temperature increase in order to minimize the errors arising due the drastic loss of moisture by wood. The gravimetric method was used to evaluate the drying process, the specimens have theirs mass measured every 6 hours until the timber reached the theoretical anhydrous state. The drying curve of rubber wood obtained here can be used to estimate the drying time of this species for different kiln temperature settings.

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.

Energetic and Exergetic Analysis of the Clay Bricks Drying in an Industrial Tunnel Dryer

2016 ◽  
Vol 369 ◽  
pp. 104-109 ◽  
Author(s):  
G.S. Almeida ◽  
F.V.S. Tavares ◽  
W.M.P.B. Lima ◽  
A.G. Barbosa de Lima
Keyword(s):  
Experimental Data ◽  
Theoretical Model ◽  
Moisture Content ◽  
Theoretical Study ◽  
Clay Bricks ◽  
Tunnel Dryer ◽  
Energy And Exergy ◽  
Exergetic Analysis ◽  
Good Agreement ◽  
Hollow Bricks

The purpose of this paper is to present a theoretical study of industrial hollow bricks drying in across flow tunnel dryer. The theoretical model is based on the 1st and 2nd laws of Thermodynamic applied to the system. To validate the methodology, numerical and experimental data of the moisture content of the brick during the drying in an industrial scale are compared and a good agreement was obtained. Results of moisture content and temperature of the product and air, and energy and exergy efficiencies are presented and analysed.

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