Numerical Prediction and Analysis of Surface Transfer Coefficients on Moist Object During Heat and Mass Transfer Application

Chandramohan, V.P.

doi:10.1080/01457632.2015.1042341

Cited by 34 publications

(7 citation statements)

References 18 publications

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“…Such a 1:1 ratio lies within the typical range of values evaluated in previous studies(Kumar et al, 2014). The drying conditions for the base case are typical for forced convective drying(Ateeque et al, 2014;Chandramohan, 2015)(CHTC = 100 W/m 2 K) at elevated temperatures (T ref,d = 40°C) with dry air (RH ref,d = 10%). The conditions during tempering (CHTC = 10 W/m 2 K, T ref,t = 20°C) are typical for an ambient environment outside the dryer.…”

supporting

confidence: 74%

Towards more efficient intermittent drying of fruit: Insights from combined hygrothermal-quality modelling

Defraeye

2016

Innovative Food Science & Emerging Technologies

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Intermittent drying is a promising alternative to continuous drying, as it enables moisture redistribution during tempering periods, leading to higher effective drying rates when the process is started again. This strategy can effectively reduce the net residence time in the dryer, which can help save process energy and increase product throughput. The milder temperature conditions that occur during tempering can also be beneficial for fruit quality. Intermittent drying is analyzed, in a new way, by combining hygrothermal simulations of the drying process with a temperature-dependent kinetic model for fruit quality degradation during drying. This method enabled to quantify the total process time of the fruit, the effective residence time in the dryer but also product quality degradation. By means of a parametric study, we obtained new insights in the impact of tempering time, total cycle time for drying and the ambient humidity conditions during tempering. By intermittent drying, the residence time could be reduced successfully without compromising fruit quality. Industrial relevance. The modelling strategy provides combined information on the water activity level in the fruit and the fruit quality state during drying. This enables, in a unique way, to optimize the drying process conditions for intermittent drying in order to achieve fast drying and still obtain prime product quality. Thereby a better identification of possible savings in energy and processing time is possible for intermittent drying and their relation to the final quality of the fruits.

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supporting

confidence: 74%

Towards more efficient intermittent drying of fruit: Insights from combined hygrothermal-quality modelling

Defraeye

2016

Innovative Food Science & Emerging Technologies

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“…(2)) which is not accounted for in the wet bulb temperature predictions. Some modelling studies, which did not account for the latent heat of evaporation (Cai et al, 2014;Chandramohan, 2015;Esfahani et al, 2014), found a steadily increasing temperature without this initial temperature drop.…”

Section: General Drying Characteristicsmentioning

confidence: 99%

Convective drying of fruit: Role and impact of moisture transport properties in modelling

Defraeye

Verboven

2017

Journal of Food Engineering

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Continuum modelling of fruit dehydration relies on accurate predictions of moisture permeability or diffusivity. These properties are often taken from literature instead of being explicitly determined for the species, cultivar or drying application of interest. As a large variability on these moisture transport properties is reported, this study targets their role and impact on simulations of the fruit drying process. Using a validated hygrothermal model, significant differences in drying rate and internal moisture content distribution are quantified for a realistic range of tissue permeabilities. Particular differences in drying kinetics are identified between constant permeability and diffusivity formulations, but in general both exhibited roughly similar drying behavior. Previous contradictory findings on the impact of the air speed, thus convective transfer coefficients (CTCs), on the drying process are shown to be most likely related to the magnitude of the tissue permeability. A lower sensitivity of the drying process to the CTCs is found for low permeabilities. A new parameter is introduced to facilitate quantitative comparison of multiple drying processes, namely by characterizing each drying curve with a single characteristic value. This modelling study provides a better quantitative insight in the fruit drying behavior and its link to the moisture transport properties of the tissue. 2012; Kurnia et al., 2013), the diffusivity for liquid transport is difficult to determine separately for a complex soft material as fruit tissue. Furthermore, for modelling the rate of evaporation, also empirical rate constants are required if vapor and liquid phases are assumed to be not in equilibrium. As such, the accuracy of such more physically correct models still relies on the used parameters.

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“…Increase the drying temperature from 313 to 353 degrees Celsius, and you will save around 40% of the drying time, according to research [ 32 ]. Furthermore, with constant and varied surface transfer coefficients, the distribution of moisture did not change any more than before [ 33 ]. Tables 1 and Tables 2 provide the governing equations and boundary conditions, respectively, which are utilized in the food sector for modeling to dry products and ingredients.…”

Section: Main Textmentioning

confidence: 99%

A Comprehensive Review of Mathematical Modeling for Drying Processes of Fruits and Vegetables

Akter

Muhury

Sultana

et al. 2022

International Journal of Food Science

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Drying fruits and vegetables is a procedure of food preservation with simultaneous heat, mass, and momentum transfer, which increases the shelf life of the food product. The aim of this review was to provide an overview of the researches on mathematical modeling for drying of fruits and vegetables with the special emphasis on the computational approach. Various heat-mass transport models, their applications, and modern drying technologies to the food industry have been reported in this study. Computational fluid dynamics, a new approach for solving heat and mass transfer problems, increases the accuracy of the predicted values. To investigate the parameters of drying needs a significant amount of time as well as costly laboratory and experimental efforts. Therefore, computational modeling could be an effective alternative to experimental approaches. This review will be beneficial for future studies in drying processes, especially for modeling, analysis, design, and optimization of food science and food engineering.

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Numerical Prediction and Analysis of Surface Transfer Coefficients on Moist Object During Heat and Mass Transfer Application

Cited by 34 publications

References 18 publications

Towards more efficient intermittent drying of fruit: Insights from combined hygrothermal-quality modelling

Towards more efficient intermittent drying of fruit: Insights from combined hygrothermal-quality modelling

Convective drying of fruit: Role and impact of moisture transport properties in modelling

A Comprehensive Review of Mathematical Modeling for Drying Processes of Fruits and Vegetables

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