scholarly journals Mathematical Modelling the Drying Kinetics of Beetroot Strips during Convective Drying at Different Temperatures

2019 ◽  
Vol 4 (2) ◽  
pp. 140-149
Author(s):  
S. S. Manjunatha ◽  
P. S. Raju
Keyword(s):  
Air Temperature ◽  
Large Scale ◽  
Moisture Diffusivity ◽  
Effective Moisture Diffusivity ◽  
Convective Drying ◽  
Effective Moisture ◽  
Kinetic Coefficients ◽  
Thin Layer Drying ◽  
Drying Kinetic ◽  
Drying Behaviour

The thin layer drying of beetroot strips was evaluated at drying temperatures from 60 °C to 90 °C using convective dryer at inlet air velocity of 1.0 m/s. The different drying models were tested to evaluate the drying characteristics of beetroot strips. The investigations showed that Page’s and modified Page’s equations were satisfactorily describing the drying behaviour of beetroot strips during convective drying with appreciable high correlation coefficient (0.9971<r<0.9990) with low error values. The effective moisture diffusivity was increased from 3.563 x 10-10 m2/s to 8.038 x 10-10 m2/s with increase in drying temperature. The temperature dependency of effective moisture diffusivity was described by Arrhenius equation and activation energy for moisture diffusivity was 30.08 KJ/mol. The drying kinetic coefficients were significantly (p<0.05) affected by drying air temperature. The exponents of models were decreased linearly with drying air temperature during drying of beetroot strips. The equilibrium moisture content was markedly affected by drying air temperature and it decreased linearly with drying air temperature. The results were very useful in standardisation and optimisation of drying process of beetroot strips in large scale commercial production.

scholarly journals Influence of Drying Conditions on the Effective Moisture Diffusivity and Energy Requirements of Ginger Slices

2014 ◽  
Vol 3 (5) ◽  
pp. 103 ◽  
Author(s):  
Tinuade J. Afolabi ◽  
Toyosi Y. Tunde-Akintunde ◽  
Olusegun J. Oyelade
Keyword(s):  
Air Temperature ◽  
Energy Requirement ◽  
Ambient Air ◽  
Moisture Diffusivity ◽  
Effective Moisture Diffusivity ◽  
Slice Thickness ◽  
Drying Time ◽  
Effective Moisture ◽  
Thin Layer Drying ◽  
Drying Conditions

<p>The thin layer drying behaviour of ginger slices in a laboratory dryer was examined. The slices of 5 mm, 10 mm and 15 mm thicknesses were dried using heated ambient air at temperatures from 40 to 70 ºC and air velocity of 1.5 m/s. The effects of drying air temperature and slice thickness on the drying characteristics, drying time and energy requirement of drying process was determined. The results have shown that an increase in the drying air temperature causes shorter drying times. Thinner slices also causes a shorter drying time. The effective moisture diffusivity values increased from 3.36814 × 10<sup>-10</sup> m<sup>2</sup>/s to 5.82524 × 10<sup>-9</sup> m<sup>2</sup>/s while the activation energy values for different slice thickness of ginger varied from 196.15 to 198.79 kJ/mol. The total needed energy varied from 735.3 to 868.5 kWh while the value of specific energy requirement varied from 3676.6 to 4342.4 kWh/kg respectively.</p>

scholarly journals Mathematical modelling of thin layer drying of pear

2016 ◽  
Vol 22 (2) ◽  
pp. 191-199 ◽  
Author(s):  
Monika Lutovska ◽  
Vangelce Mitrevski ◽  
Ivan Pavkov ◽  
Vladimir Mijakovski ◽  
Milivoj Radojcin
Keyword(s):  
Experimental Data ◽  
Thin Layer ◽  
Moisture Diffusivity ◽  
Effective Moisture Diffusivity ◽  
Data Set ◽  
Effective Moisture ◽  
Air Temperatures ◽  
Thin Layer Drying ◽  
Drying Kinetic ◽  
Drying Conditions

In this study, a thin - layer drying of pear slices as a function of drying conditions were examined. The experimental data set of thin - layer drying kinetics at five drying air temperatures 30, 40, 50, 60 and 70?C, and three drying air velocities 1, 1.5 and 2 m s-1 were obtained on the experimental setup, designed to imitate industrial convective dryer. Five well known thin - layer drying models from scientific literature were used to approximate the experimental data in terms of moisture ratio. In order to find which model gives the best results, numerical experiments were made. For each model and data set, the statistical performance index, (?), and chi-squared, (?2), value were calculated and models were ranked afterwards. The performed statistical analysis shows that the model of Midilli gives the best statistical results. Because the effect of drying air temperature and drying air velocity on the empirical parameters was not included in the base Midilli model, in this study the generalized form of this model was developed. With this model, the drying kinetic data of pear slices can be approximated with high accuracy. The effective moisture diffusivity was determined by using Fick?s second laws. The obtained values of the effective moisture diffusivity, (Deff), during drying ranged between 6.49 x 10-9 and 3.29 x 10-8 m2 s-1, while the values of activation energy (E0) varied between 28.15 to 30.51 kJ mol-1.

Modeling Some Drying Characteristics of Cantaloupe Slices

2012 ◽  
Vol 45 (2) ◽  
pp. 5-14 ◽  
Author(s):  
R. Chayjan ◽  
H. Agha-Alizade ◽  
H. Barikloo ◽  
B. Soleymani
Keyword(s):  
Air Temperature ◽  
Specific Energy ◽  
Specific Energy Consumption ◽  
Initial Moisture Content ◽  
Moisture Diffusivity ◽  
Convective Drying ◽  
Drying Characteristics ◽  
Thin Layer Drying ◽  
Temperature Levels ◽  
Drying Conditions

Modeling Some Drying Characteristics of Cantaloupe Slices This study investigated thin layer drying of cantaloupe slices under different drying conditions with initial moisture content about 18.53 (d.b.). Air temperature levels of 40, 50, 60 and 70°C were applied in drying of samples. Fick's second law in diffusion was applied to compute the effective moisture diffusivity (Deff) of cantaloupe slices. Minimum and maximum values of Deff were 4.05x10-10 and 1.61x10-9 m2/s, respectively. Deff values increased as the input air temperature was increased. Activation energy values of cantaloupe slices were found between 30.43 and 36.23 kJ/mol for 40°C to 70°C, respectively. The specific energy consumption for drying cantaloupe slices was calculated at the boundary of 1.01x105 and 9.55x105 kJ/kg. Increasing in drying air temperature in different air velocities led to increase in specific energy value. Results showed that applying the temperature of 70°C is more effective for convective drying of cantaloupe slices. The aforesaid drying parameters are important to select the best operational point of a dryer and to precise design of the system.

scholarly journals Kinetics, energy efficiency and mathematical modeling of thin layer solar drying of figs (Ficus carica L.)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lahcen Hssaini ◽  
Rachida Ouaabou ◽  
Hafida Hanine ◽  
Rachid Razouk ◽  
Ali Idlimam
Keyword(s):  
Energy Efficiency ◽  
Thin Layer ◽  
Air Flow ◽  
Moisture Diffusivity ◽  
Energy Utilization ◽  
Ficus Carica ◽  
Effective Moisture Diffusivity ◽  
Drying Time ◽  
Effective Moisture ◽  
Thin Layer Drying

AbstractFirst convectional thin layer drying of two fig (Ficus carica L.) varieties growing in Moroccan, using partially indirect convective dryer, was performed. The experimental design combined three air temperatures levels (60, 70 and 80 °C) and two air-flow rates (150 and 300 m3/h). Fig drying curve was defined as a third-order polynomial equation linking the sample moisture content to the effective moisture diffusivity. The average activation energy was ranged between 4699.41 and 7502.37 kJ/kg. It raised proportionally with the air flow velocity, and the same pattern were observed for effective moisture diffusivity regarding drying time and velocity. High levels of temperature (80 °C) and velocity (300 m3/h) lead to shorten drying time (200 min) and improve the slices physical quality. Among the nine tested models, Modified Handerson and Pabis exhibited the highest correlation coefficient value with the lowest chi-square for both varieties, and then give the best prediction performance. Energetic investigation of the dryer prototype showed that the total use of energy alongside with the specific energy utilization (13.12 and 44.55 MWh/kg) were inversely proportional to the velocity and drying temperature. Likewise, the energy efficiency was greater (3.98%) higher in drying conditions.

scholarly journals Drying characteristics of eggplant (Solanum melongena L.) slices under microwave-convective drying

2016 ◽  
Vol 62 (No. 4) ◽  
pp. 170-178 ◽  
Author(s):  
R.A. Chayjan ◽  
M. Kaveh
Keyword(s):  
Air Temperature ◽  
Microwave Power ◽  
Specific Energy Consumption ◽  
Solanum Melongena ◽  
Moisture Diffusivity ◽  
Moisture Ratio ◽  
Convective Drying ◽  
Air Velocity ◽  
Drying Time ◽  
Thin Layer Drying

A laboratory scale microwave-convection dryer was used to dry the eggplant fruit, applying microwave power in the range of 270–630 W, air temperature in the range of 40–70°C and air velocity in the range of 0.5–1.7 m/s. Six mathematical models were used to predict the moisture ratio of eggplant fruit slices in thin layer drying. The results showed that the Midilli et al. model had supremacy in prediction of turnip slice drying behavior. Minimum and maximum values of effective moisture diffusivity (D<sub>eff</sub>) were 1.52 × 10<sup>–9</sup> and 3.39 × 10<sup>–9</sup> m<sup>2</sup>/s, respectively. Activation energy values of eggplant slices were found between 13.33 and 17.81 kJ/mol for 40°C to 70°C, respectively. The specific energy consumption for drying eggplant slices was calculated at the boundary of 86.47 and 194.37 MJ/kg. Furthermore, in the present study, the application of Artificial Neural Network (ANN) for predicting the drying rate and moisture ratio was investigated. Microwave power, drying air temperature, air velocity and drying time were considered as input parameters for the model.

Drying Simulation of Shrinkable Clay Tiles Using Variable Diffusivity Model

2013 ◽  
Vol 837 ◽  
pp. 506-510 ◽  
Author(s):  
Miloš Vasić ◽  
Zagorka Radojević
Keyword(s):  
Moisture Diffusivity ◽  
Time Dependent ◽  
Effective Moisture Diffusivity ◽  
Experimental Investigations ◽  
Variable Diffusivity ◽  
Effective Moisture ◽  
Drying Kinetic ◽  
Constant Diffusivity ◽  
Drying Model ◽  
Clay Tiles

This paper represents the upgrade of our previous study in which we have presented a model for simulation of the drying kinetic and estimation of the effective moisture diffusivity of clay tiles using a constant diffusivity model. The main objective of this study is to determine the time - dependent effective moisture diffusivity of shrinkable clay tiles. Experimental investigations were carried out, on clay tiles, in a laboratory recirculation dryer in which drying parameters (humidity, temperature, and velocity) could be programmed, controlled and monitored during drying. Results presented in this study have shown that the proposed drying model describes and correlates accurately drying kinetics and gives a reliably estimation of the time - dependent effective moisture diffusivity.

Drying Kinetic Simulation of Clay Tiles Made from the Raw Material Having Less Clay Fraction

2014 ◽  
Vol 1036 ◽  
pp. 3-8
Author(s):  
Miloš Vasić ◽  
Zagorka Radojević
Keyword(s):  
Clay Fraction ◽  
Effective Diffusivity ◽  
Moisture Diffusivity ◽  
Effective Moisture Diffusivity ◽  
Diffusivity Coefficient ◽  
Moisture Movement ◽  
Effective Moisture ◽  
Drying Kinetic ◽  
Clay Tiles

In order to describe the internal moisture rate and to take all different mechanisms of moisture movement into account, it is suitable to use effective diffusivity as a measure of moisture rate, irrespectively of the mechanisms really involved. This means that all different mechanisms and driving forces for internal moisture transport are lumped together and introduced into effective moisture diffusivity. Hence, diffusion equations are retained and reused with the effective diffusivity coefficient as a measuring parameter of internal moisture ratio. In our previous studies we have presented the calculation method which assumed constant diffusivity. The next goal was to estimate effective diffusivity at various moisture contents, in a real case of non-linear drying curves, and to predict drying kinetic. In our last study we have developed a model for determination of the variable effective diffusivity and identification of the exact transition points between possible drying mechanisms. In this paper we have tried to develop more accurate tool for determination of time dependent effective moisture diffusivity. An analytical model and computing procedure were developed to evaluate mass transfer properties and describe drying kinetic of clay tiles having less clay fraction. The proposed procedure was validated with experimental drying data. Presented results have demonstrated that the proposed dying model can be applied for the accurate description of experimental drying kinetics and a reliable estimation of effective diffusivity.

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