Drying Behavior of Polyester Based Yarn Bobbins in a Hot-Air Bobbin Dryer

2011 ◽  
Vol 312-315 ◽  
pp. 848-853
Author(s):  
Ahmet Cihan ◽  
Kamil Kahveci ◽  
Ugur Akyol ◽  
Dinçer Akal
Keyword(s):  
Mass Transfer ◽  
Diffusion Coefficient ◽  
Textile Industry ◽  
Diffusion Mechanism ◽  
Moisture Ratio ◽  
Transfer Model ◽  
Hot Air ◽  
Air Temperatures ◽  
Drying Behavior ◽  
Good Agreement

Drying behavior of polyester based yarn bobbins (67% polyester, 33% viscose) was simulated for different drying air temperatures by a simultaneous heat and mass transfer model. In the model, it was assumed that mass transfer is occurred by the diffusion mechanism. In the study, firstly drying behavior of polyester bobbins for different drying air temperatures has been determined experimentally. The experiments were conducted on an experimental hot-air bobbin dryer designed and manufactured based on hot-air bobbin dryers used in textile industry. In the experimental setup, temperatures of different points of the bobbins were measured by thermocouples placed inside the bobbins and weight of the bobbins during the drying period were determined by a load cell. Then moisture ratio and temperature values of the model have been fitted to the experimental ones. The fit was performed by selecting the values for the diffusion coefficient and the thermal diffusivity in the model in such a way that these values make the sum of the squared differences between the experimental and the model results for moisture ratio and temperature minimum. The results show that there is a good agreement between the model results and the experimental ones. The results also show that temperature has a significant effect on mass transfer and temperature dependence of the diffusion coefficient may be explained by an Arrhenius type relation.

Simulation of Drying Behavior of Cotton Bobbins by a Simultaneous Heat and Mass Transfer Model

2011 ◽  
Vol 312-315 ◽  
pp. 854-859
Author(s):  
Ugur Akyol ◽  
Kamil Kahveci ◽  
Ahmet Cihan ◽  
Dinçer Akal
Keyword(s):  
Mass Transfer ◽  
Diffusion Coefficient ◽  
Heat And Mass Transfer ◽  
Textile Industry ◽  
Moisture Ratio ◽  
Transfer Model ◽  
Mass Transfer Model ◽  
Air Temperatures ◽  
Drying Behavior ◽  
Simultaneous Heat

In this study, the drying process of cotton bobbins for different drying air temperatures has been simulated by a simultaneous heat and mass transfer model. In the model, the mass transfer is assumed to be controlled by diffusion. In order to make the simulation, firstly, drying behavior of cotton bobbins for different drying air temperatures has been determined on an experimental bobbin dryer setup which was designed and manufactured based on hot-air bobbin dryers used in textile industry. In the experimental setup, temperatures of different points in cotton bobbins were measured by thermocouples placed inside the bobbins, and weights of the bobbins during the drying period were determined by means of a load cell. Then, moisture ratio and temperature values of the model have been fitted to the experimental ones. The fit was performed by selecting the values for the diffusion coefficient and the thermal diffusivity in the model in such a way that these values make the sum of the squared differences between the experimental and the model results for moisture ratio and temperature minimum. Results show that there is a good agreement between the model results and the experimental measurements. The results also show that temperature has a significant effect on mass transfer and the temperature dependence of the diffusion coefficient may be expressed by an Arrhenius type relation.

Mass Transfer Parameters and Modeling of Hot Air Drying Kinetics of Dill Leaves

2016 ◽  
Vol 12 (2) ◽  
Author(s):  
Hosain Darvishi ◽  
Zanyar Farhudi ◽  
Nasser Behroozi-Khazaei
Keyword(s):  
Activation Energy ◽  
Mass Transfer ◽  
Moisture Content ◽  
Moisture Diffusivity ◽  
Drying Kinetics ◽  
Transfer Model ◽  
Hot Air ◽  
Drying Behavior ◽  
Kinetics Of ◽  
Best Fit

Abstract Moisture diffusivity (Dem), mass transfer coefficient (hm), activation energy and drying kinetics of the dill leaves were studied and modeled as a function of temperature (40–70 °C) and moisture content (0.20–5.67 kg water/kg dry matter). Results showed that the Dem and hm significantly depend on the temperature and moisture content (p < 0.05). The average of Dem and hm varied between 4.02 × 10–9 to 9.65 × 10–9 m2/s, and 2.38 × 10–7 to 6.33 × 10–7 m/s, respectively. Activation energy showed a significant dependence on the moisture content and estimated as 16.84 kJ/mol for diffusion model and 28.70 kJ/mol for mass transfer model. Out of the six models considered, the logarithmic model showed the best fit to drying behavior of the dill leaves.

scholarly journals Numerical Simulation of Heat and Mass Transfer Along with Shrinkages in Brinjal (Eggplant/Solonummelongena)

2019 ◽  
Vol 8 (4) ◽  
pp. 2867-2872
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Food Quality ◽  
Drying Shrinkage ◽  
Moisture Distribution ◽  
Transfer Model ◽  
Drying Process ◽  
Ambient Conditions ◽  
Food Material ◽  
Hot Air

Heat and mass transfer plays a major role in food processing. During storage of food due to environmental conditions, the food is dehydrated and leads to a loss in weight. To maintain the food quality, basically drying method is used. Food material with a high quantity of moisture content experiences shrinkage during the drying process. The main aim of this present work was to simulate the drying shrinkage-deformation mechanism of Solonum Melongena (Eggplant/Brinjal) during the drying process. Heat and mass transfer model is coupled with structural mechanics and solved by COMSOL Multi physics tool. The mathematical model is validated by hot air drying experiment, for different temperature condition was conducted to study the heat and mass transfer along with deformations, including stresses. Temperature and moisture distribution of brinjal (eggplant) during drying were uniform, during drying material changes in shapes/dimensions. This prediction of results will help maintain the ambient conditions and preserve food quality.

The Effects of Micro Scale Solute Redistribution on the Macro Scale Heat and Mass Transfer During Casting Processes

2005 ◽  
Author(s):  
Hong Nie ◽  
Yan-Hui Feng ◽  
Xin-Xin Zhang
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Transfer Model ◽  
Back Diffusion ◽  
Mass Transfer Model ◽  
One Dimensional ◽  
Solidification Model ◽  
Casting Technology ◽  
Macro Scale ◽  
Good Agreement

One-dimensional plate-like dendritic model is built to describe the microsegregation during binary alloy solidification with solid back-diffusion and complete diffusion in the liquid. The specialties of microsegregation for Al-Cu and Fe-C alloys are analyzed and compared by simulation. Moreover, the microsegregation model is developed to couple with the macro solidification model which simulates the heat and mass transfer with phase change for the new Inverse Casting Technology. The numerical results are proven to be in good agreement with experimental data. It shows that the microsegregation numerical model can reflect the micro mass transfer accurately and can be coupled reliably with macro heat and mass transfer model for solidification. In addition, both the micro and macro investigation shows that the solidification of Fe-C alloy progresses almost in equilibrium.

Mass transfer coefficients for an autotrophic and a heterotrophic biofilm system

1995 ◽  
Vol 32 (8) ◽  
pp. 199-204 ◽  
Author(s):  
H. Horn ◽  
D. C. Hempel
Keyword(s):  
Mass Transfer ◽  
Diffusion Coefficient ◽  
Transfer Coefficient ◽  
Transfer Model ◽  
Mass Transfer Model ◽  
Transfer Coefficients ◽  
Mass Transfer Coefficients ◽  
Heterotrophic Microbes ◽  
Oxygen Microelectrodes ◽  
Oxygen Profiles

To evaluate the mass transfer coefficients at the interface bulk/biofilm two biofilm systems with autotrophic and heterotrophic microbes were investigated with oxygen microelectrodes over a longterm period (1 year). To determine the transfer coefficient the oxygen profiles were simulated with a mass transfer model and compared with the measured substrate flux. The oxygen profiles at flow velocities &gt;10 cm/s yielded concentration layers of about 100 μm and transfer coefficients &gt; 10−4 m/s. These evaluated transfer coefficients were one magnitude higher than those known from hydrodynamics without biofilm reactions. Thus, the assumption, which determines the transfer coefficient as a quotient of the diffusion coefficient through the thickness of the laminar sublayer is oversimplified.

scholarly journals Validation and Optimization of Heat and Mass Transfer Model for Mushroom Convection Drying

2021 ◽  
Vol 293 ◽  
pp. 03011
Author(s):  
Huimin Shan ◽  
Kongqing Li
Keyword(s):  
Resistance Coefficient ◽  
Transfer Model ◽  
Hot Air Drying ◽  
Drying Time ◽  
Simulation Accuracy ◽  
Hot Air ◽  
Air Supply ◽  
Computational Fluid Dynamics Cfd ◽  
Drying System ◽  
Good Agreement

In order to solve the problems of time consuming, energy consumption and low simulation accuracy in the hot air-drying system of food drying. Using computational fluid dynamics (CFD) to simulate the drying process of mushrooms can provide a reference for its technology research and development (R&D). The porous media approach was used to model the flow resistance offered by the mushroom. The resistance coefficient and porosity were determined through the experiments. Different air supply ways (wind speed, temperature, fresh air volume, reverse air supply period) were simulated and two optimize ways were suggested according the shortest possible drying time. The simulation results are in good agreement with the experimental results. The air supply way of periodic with reverse (SMPR), which means timed alternate the direction of air flow, or the way of mix in fresh air intermittently can effectively shorten the drying time. Considering comprehensively, the optimal air supply way was the mix in fresh air intermittently with fresh air accounts for 30% or SMPR with the period of 2h under the condition of the hot air temperature of 55°C and wind velocity of 0.6m/s.

A Transient Heat and Mass Transfer Model of Residential Attics Used to Simulate Radiant Barrier Retrofits, Part I: Development

1998 ◽  
Vol 120 (1) ◽  
pp. 32-38 ◽  
Author(s):  
M. A. Medina ◽  
D. L. O’Neal ◽  
W. D. Turner
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Heat Fluxes ◽  
Dew Point ◽  
Weather Data ◽  
Transfer Model ◽  
Mass Transfer Model ◽  
Air Temperatures ◽  
Gain Loss ◽  
Heating Loads

This paper describes a transient heat and mass transfer model of residential attics. The model is used to predict hourly ceiling heat gain/loss in residences with the purpose of estimating reductions in cooling and heating loads produced by radiant barriers. The model accounts for transient conduction, convection, and radiation and incorporates moisture and air transport across the attic. Environmental variables, such as solar loads on outer attic surfaces and sky temperatures, are also estimated. The model is driven by hourly weather data which include: outdoor dry bulb air temperature, horizontal solar and sky radiation, wind speed and direction, relative humidity (or dew point), and cloud cover data. The output of the model includes ceiling heat fluxes, inner and outer heat fluxes from all surfaces, inner and outer surface temperatures, and attic dry bulb air temperatures. The calculated fluxes have been compared to experimental data of side-by-side testing of attics retrofit with radiant barriers. The model predicts ceiling heat flows with an error of less than ten percent for most cases.

scholarly journals Mathematical model of germinated paddy drying

2019 ◽  
Vol 1 (1) ◽  
pp. 48-52
Author(s):  
Hathaichanok Netkham ◽  
Supawan Tirawanichakul ◽  
Sirinuch Chindaruksa ◽  
Yutthana Tirawanichakul
Keyword(s):  
Mathematical Model ◽  
Moisture Content ◽  
Empirical Model ◽  
Infrared Radiation ◽  
Radiation Power ◽  
Drying Temperature ◽  
Hot Air ◽  
Air Temperatures ◽  
Drying Behavior

The objective of this research was to predict the moisture content of Sang Yod germinated paddy with infrared radiation power value of 1,000 watts at 60, 80 and 100 °C and hot air temperatures of velocity 1.1 m/s at 60, 80 and 100°C using empirical model. In this research, the moisture content of the dried samples was compared with the moisture content of the drying using the empirical model. The results showed that Verma model was most suitable to describe the drying behavior of germinated paddy at 60, 80 and 100 °C drying temperature when dried with infrared and hot air.

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