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Ratthasak Prommas - One of the best experts on this subject based on the ideXlab platform.
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theoretical and experimental study of heat and mass transfer mechanism during Convective Drying of multi layered porous packed bed
International Communications in Heat and Mass Transfer, 2011Co-Authors: Ratthasak PrommasAbstract:Abstract In this paper, the experimental validation of a combined mass and thermal model for a Convective Drying of multi-layered packed beds composed of glass beads, water and air is presented. The effects of the Drying time, particle size and the layered structure on the overall Drying kinetics are clarified in detail. Based on a completed model combining the temperature, total pressure and moisture equations, the results show that the Convective Drying kinetics strongly depend on the particle size as well as hydrodynamic properties and layered structure, considering the interference between capillary flow and vapor diffusion in the multi-layered porous packed bed. The predicted results are in a good agreement with the experimental results.
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energy and exergy analyses in Convective Drying process of multi layered porous packed bed
International Communications in Heat and Mass Transfer, 2010Co-Authors: Ratthasak Prommas, Pornthip Keangin, Phadungsak RattanadechoAbstract:This paper is concerned with the investigation of the energy and exergy analyses in Convective Drying process of multi-layered porous media. The Drying experiments were conducted to find the effects of multi-layered porous particle size and thermodynamics conditions on energy and exergy profiles. An energy analysis was performed to estimate the energy utilization by applying the first law of thermodynamics. An exergy analysis was performed to determine the exergy inlet, exergy outlet, exergy losses during the Drying process by applying the second law of thermodynamics. The results show that the energy utilization ratio (EUR) and the exergy efficiency depend on the particle size as well as the hydrodynamic properties and the layered structure, by considering the interference between capillary flow and vapor diffusion in the multi-layered packed bed.
G P Sharma - One of the best experts on this subject based on the ideXlab platform.
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dehydration kinetics of onion slices in osmotic and air Convective Drying process
Research in Agricultural Engineering, 2018Co-Authors: V A Revaskar, Pankaj B Pathare, P S Pisalkar, G P SharmaAbstract:Revaskar V.A., Pisalkar P.S., Pathare P.B., Sharma G.P., 2014. Dehydration kinetics of onion slices in osmotic and air Convective Drying process . Res. Agr. Eng., 60: 92–99. The effect of different pre-treatments ( i.e. osmotic dehydration in 10, 15 and 20°Brix NaCl solution and Drying air temperature of 50, 60 and 70°C) on Drying behaviour of onion slices were investigated. The onion slices were dried in a laboratory model tray dryer. Drying of onion slices occurred in falling rate period. Five thin-layer Drying models (Ex ponential, Page, Henderson and Pabis, Logarithmic and Power law) were fitted to the moisture ratio data. Among the Drying models investigated, the Page model satisfactorily described the Drying behaviour of onion slices. The effective moisture diffusivity of pre-treated samples was higher than that of non-treated samples.
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effective moisture diffusivity of onion slices undergoing infrared Convective Drying
Biosystems Engineering, 2006Co-Authors: Pankaj B Pathare, G P SharmaAbstract:Drying experiments of onion slices (6 mm thickness) were carried out by using infrared Convective Drying. Infrared Convective Drying of onion slices was observed to be a falling rate process. The average effective moisture diffusivity of onion slices ranged between 0·2514×10 −10 and 0·3233×10 −10 m 2 s −1 . The values of average effective moisture diffusivity increased for the same values of Drying air temperature and air velocity as applied radiation intensity was increased. Average effective moisture diffusivity decreased at all air temperature and applied radiation intensity with increase in air velocity. The activation energy in infrared Convective Drying between 5·06 and 10·63 kJ mol −1 . It has been indicated that decrease in energy of activation caused an increase in Drying rate.
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effective moisture diffusivity of garlic cloves undergoing microwave Convective Drying
Journal of Food Engineering, 2004Co-Authors: G P Sharma, Suresh PrasadAbstract:Abstract Drying of garlic cloves was done using microwave-Convective technique, using microwave power of 10–40 W, air temperature of 40–70 °C and at air velocity of 1–2 m/s. The effective moisture diffusivity varied from 1.29 to 31.68 × 10 −10 m 2 /s. A third order polynomial relationship was found to correlate the effective moisture diffusivity ( D eff ) with moisture content. The D eff increased for the same values of Drying air temperatures and velocities as the applied microwave power was increased. However, D eff decreased at all temperatures and applied microwave power with increase in air velocity. The activation energy in the microwave-Convective Drying ranged between 4.08 and 10.50 kJ/mol, which was much lower than the convectionally heating activation energy values for moisture diffusivities for most vegetables.
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Drying kinetics of garlic cloves under Convective Drying conditions
Journal of Food Science and Technology-mysore, 2003Co-Authors: G P Sharma, Suresh Prasad, Ajanta DattaAbstract:Convective Drying of garlic cloves was carried out at Drying air temperatures of 40, 50, 60 and 70°C at air velocities of 1 m/s and 2 m/s, respectively. Peeled garlic cloves weighing about 100 g were used in each Drying experiment. The cloves were almost of uniform size having length of 20.1mm and diameter of 7.2 mm. The Drying rate increased with the increase in Drying air temperature, thus reducing the Drying time. Air velocity showed no significant effect on the Drying time. The moisture diffusivity of the garlic cloves ranged between 0.348 x 10 -10 and 2.36 x 10 -10 m 2 /s. The moisture diffusivity increased with increase in air temperature and velocity, and with decrease in moisture content. The activation energy in the convectional Drying ranged between 9.48 and 10.46 kJ/mole. The modified logarithmic Page's equation fitted well and described the Convective Drying behaviour of the garlic cloves.
Phadungsak Rattanadecho - One of the best experts on this subject based on the ideXlab platform.
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energy and exergy analyses in Convective Drying process of multi layered porous packed bed
International Communications in Heat and Mass Transfer, 2010Co-Authors: Ratthasak Prommas, Pornthip Keangin, Phadungsak RattanadechoAbstract:This paper is concerned with the investigation of the energy and exergy analyses in Convective Drying process of multi-layered porous media. The Drying experiments were conducted to find the effects of multi-layered porous particle size and thermodynamics conditions on energy and exergy profiles. An energy analysis was performed to estimate the energy utilization by applying the first law of thermodynamics. An exergy analysis was performed to determine the exergy inlet, exergy outlet, exergy losses during the Drying process by applying the second law of thermodynamics. The results show that the energy utilization ratio (EUR) and the exergy efficiency depend on the particle size as well as the hydrodynamic properties and the layered structure, by considering the interference between capillary flow and vapor diffusion in the multi-layered packed bed.
Jan Carmeliet - One of the best experts on this subject based on the ideXlab platform.
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influence of uncertainty in heat moisture transport properties on Convective Drying of porous materials by numerical modelling
Chemical Engineering Research & Design, 2013Co-Authors: Twj Thijs Defraeye, Bje Bert Blocken, Jan CarmelietAbstract:The influence of uncertainties in heat-moisture transport properties, due to measurement errors and material heterogeneity, on the numerical simulation results of Convective Drying of two capillary-saturated porous materials is investigated by a transport-property parameter analysis (TP-PA), based on the Monte Carlo method. Here, the heat-air-moisture transfer model is evaluated many times, each time using a random set of one or multiple input parameters (i.e. transport properties), by which a stochastic model output is generated. The propagation of these transport-property uncertainties to the hygrothermal behaviour of the Drying system is evaluated by statistical analysis of the model simulation output. The spread on the hygrothermal response is found to be strongly material dependent and is related to the dominant mode of moisture transport in the material, i.e. liquid or vapour transport. The TP-PA results clearly indicate that uncertainties in the heat-moisture transport properties can lead to significant differences in Drying behaviour predictions, where differences of the total Drying time with respect to its mean value up to 200% are found for the materials considered. Therefore, numerical modelling of heat and moisture transport in porous materials should preferably include a quantification of the propagation of these uncertainties, for example by means of the proposed transport-property parameter analysis. Such analysis however additionally requires detailed (a-priori) experimental material characterisation to determine realistic uncertainty ranges.
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analysis of Convective heat and mass transfer coefficients for Convective Drying of a porous flat plate by conjugate modelling
International Journal of Heat and Mass Transfer, 2011Co-Authors: Twj Thijs Defraeye, Bje Bert Blocken, Jan CarmelietAbstract:Convective Drying of an unsaturated porous flat plate at low Reynolds numbers (103) is analysed by means of conjugate modelling of heat and mass transport in the air flow and the porous material. Conjugate modelling does not require knowledge of Convective transfer coefficients (CTCs) but allows determining the CTCs a posteriori, hence identifying their spatial and temporal variability, which is the main focus of this study. Comparison is made with porous-material modelling using spatially and/or temporally constant CTCs. Both spatial and temporal variations of the Convective boundary conditions are found to have a distinct impact on the Drying behaviour: the spatial CTC variation results in two-dimensional Drying of the porous material due to leading-edge effects; the temporal CTC variation identifies distinct maxima in the Drying rates at the surface right before the surface dries out locally. The CTCs obtained with conjugate modelling remain approximately constant during the constant and decreasing Drying rate period (CDRP and DDRP, respectively), but a distinct variation is noticed at the transition of CDRP to DDRP. The heat and mass transfer analogy is found to be valid during the CDRP and to a lesser extent during the DDRP but large discrepancies are found during the transition of CDRP to DDRP. The advantages of conjugate modelling are indicated in this study but the need for detailed modelling of Convective boundary conditions is however strongly dependent on the Drying behaviour of the porous material and is not always required.
Suresh Prasad - One of the best experts on this subject based on the ideXlab platform.
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effective moisture diffusivity of garlic cloves undergoing microwave Convective Drying
Journal of Food Engineering, 2004Co-Authors: G P Sharma, Suresh PrasadAbstract:Abstract Drying of garlic cloves was done using microwave-Convective technique, using microwave power of 10–40 W, air temperature of 40–70 °C and at air velocity of 1–2 m/s. The effective moisture diffusivity varied from 1.29 to 31.68 × 10 −10 m 2 /s. A third order polynomial relationship was found to correlate the effective moisture diffusivity ( D eff ) with moisture content. The D eff increased for the same values of Drying air temperatures and velocities as the applied microwave power was increased. However, D eff decreased at all temperatures and applied microwave power with increase in air velocity. The activation energy in the microwave-Convective Drying ranged between 4.08 and 10.50 kJ/mol, which was much lower than the convectionally heating activation energy values for moisture diffusivities for most vegetables.
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Drying kinetics of garlic cloves under Convective Drying conditions
Journal of Food Science and Technology-mysore, 2003Co-Authors: G P Sharma, Suresh Prasad, Ajanta DattaAbstract:Convective Drying of garlic cloves was carried out at Drying air temperatures of 40, 50, 60 and 70°C at air velocities of 1 m/s and 2 m/s, respectively. Peeled garlic cloves weighing about 100 g were used in each Drying experiment. The cloves were almost of uniform size having length of 20.1mm and diameter of 7.2 mm. The Drying rate increased with the increase in Drying air temperature, thus reducing the Drying time. Air velocity showed no significant effect on the Drying time. The moisture diffusivity of the garlic cloves ranged between 0.348 x 10 -10 and 2.36 x 10 -10 m 2 /s. The moisture diffusivity increased with increase in air temperature and velocity, and with decrease in moisture content. The activation energy in the convectional Drying ranged between 9.48 and 10.46 kJ/mole. The modified logarithmic Page's equation fitted well and described the Convective Drying behaviour of the garlic cloves.