Numerical modeling of convective drying of food with spatially dependent transfer coefficient in a turbulent flow field

Ateeque, Md.; Udayraj,; Mishra, Ranjeet K.; Chandramohan, V.P.; Talukdar, Prabal

doi:10.1016/j.ijthermalsci.2013.12.003

Cited by 60 publications

(46 citation statements)

References 25 publications

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“…), and the velocity and pressure profiles of a fluid food and/or the drying fluid (Ateeque et al . ) when the dynamic flow is included in the governing equations.…”

Section: Introductionmentioning

confidence: 99%

“…Drying mathematical models are used for the design of new systems, for improving existing ones and for process control, and are able to describe the process kinetics. They can also provide the necessary information as regard to product's moisture and temperature when approaches that include the heat and mass transfer phenomena are used (Dinani et al 2014), and the velocity and pressure profiles of a fluid food and/or the drying fluid (Ateeque et al 2014) when the dynamic flow is included in the governing equations.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Process Parameters on Foam Mat Drying Kinetics of Yacon (Smallanthus sonchifolius) and Thin‐Layer Drying Modeling of Experimental Data

Franco

Perussello

Ellendersen

et al. 2015

J Food Process Engineering

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Because of the health benefits provided by the consumption of yacon and its perishability, the foam mat drying (FMD) was applied in order to increase its shelf life. Yacon juice foams formed by the addition of two different foaming agents (emulsifier and egg albumin) and incorporation of air were subjected to dehydration, with different air temperatures (50, 60 and 70C) and layer thicknesses (0.5, 1.0 and 1.5 cm). The drying rate and effective diffusivity increase with the rise in temperature and the thickness of foam, being higher for the foam formed with egg albumin rather than emulsifier. The experimental data were fitted to several thinlayer models, among which the logarithmic model was the most suitable to represent the process. The effect of temperature, thickness and foaming agent on the drying kinetics has not been studied previously; hence, this research can aid the design of optimized FMD processes. PRACTICAL APPLICATIONSYacon is a food with great potential for research because of its beneficial properties to human health, especially the prebiotic activity, which is ascribed to the high concentration of inulin and fructooligosaccharides in its composition. However, the high percentage of water renders this tuber extremely perishable, hindering transporting and processing. The foam layer drying reduces drying time and energy demand with respect to other drying techniques and allows the formation of products with excellent physicochemical and sensorial characteristics. The assessment of the process kinetics and application of mathematical models to predict it provides information for the process design, increasing the use of yacon in the agro industry.

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“…), and the velocity and pressure profiles of a fluid food and/or the drying fluid (Ateeque et al . ) when the dynamic flow is included in the governing equations.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of Process Parameters on Foam Mat Drying Kinetics of Yacon (Smallanthus sonchifolius) and Thin‐Layer Drying Modeling of Experimental Data

Franco

Perussello

Ellendersen

et al. 2015

J Food Process Engineering

View full text Add to dashboard Cite

show abstract

“…Recently, the use of computer simulation using modeling of various engineering processes has become very popular [11][12][13][14][15][16] . This approach is very powerful, cheap and fast for predicting variations in operational parameters such as temperature and moisture, air velocity and their effect on the mechanical properties of the product.…”

Section: Introductionmentioning

confidence: 99%

“…The application of this method for understanding the dynamics of thermal transport during rice grain drying could be very valuable for quality control of rice grains during storage. Reviews of the recent studies on the application of finite element modeling that describes heat and mass transport has been limited only to either two-dimensional (2D) or threedimensional (3D) single domain models [11,13,14,[16][17][18][19][20][21] . Many of these relevant studies attempted to simplify the complex process of the heat and mass transfer in the processing operation.…”

Section: Introductionmentioning

confidence: 99%

Three-Dimensional Numerical Modeling of Convective Heat Transfer During Shallow-Depth Forced-Air Drying of Brown Rice Grains

Pérez

Tanaka

et al. 2015

Drying Technology

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We describe here a three dimensional (3D) numerical study of the convective thermal transfer during forced-air drying of brown rice grains with the inclusion of moisture evaporation. Three levels of temperature were tested across a range from 40 to 60 o C. The objective of the study was to determine the temperature distributions in the drying chamber and as well as the surface and intra-kernel temperature gradients during convective drying of rice grains. The numerical model was based on the Navier-Stokes equation for the fluid flow and the Fourier's equation for heat transfer. Results of the numerical solution showed that temperature distribution in the air and brown rice grains during the early minutes of drying were significantly influenced by the direction of flow of the heated air. Air gaps between grains and at the periphery of the drying chamber affected the rate and direction of airflow. The temperature history of the rice grains showed variations at different levels within the layer of grains. Moreover, the stream of heated air showed regions with airflows eight times than the inlet air velocity. Downloaded by [FU Berlin] at 04:09 15 May 2015 2 KEYWORDS: 3D finite element model, convective heat transfer, rice grain drying, evaporation, thermal diffusion, numerical simulation Notation: BDF Backward Differentiation Formula CFD Computational Fluid Dynamics Cp a specific heat capacity at constant pressure of air, J/kg-K Cp specific heat capacity at constant pressure of brown rice, J/kg-K GMRES Generalized Minimal Residual method k a thermal conductivity of air, W/m-K k o thermal conductivity of brown rice, W/m-K k 1 drying rate constant of brown rice, s -1 l 3x3 identity matrix M moisture content, % d.b. MR moisture ratio, dimensionless M o initial moisture content, % d.b. M i instantaneous moisture content, % d.b. M e equilibrium moisture content, % d.b. P pressure, Pa Q st latent heat of vaporization, J/g Q heat lost from evaporation, W/m 3 Re Reynolds number, dimensionless t time, s Downloaded by [FU Berlin] at 04:09 15 May 2015 3 T temperature, K T o initial/ambient temperature of air, K T ∞ maximum drying temperature of air, K u velocity vector, m/s V t total volume of grains, m 3 W d weight of dry solids, kg x,y,z Cartesian coordinates, mm ∞ infinity, supremum of the temperature ρ a density of air , kg/m 3 ρ density of brown rice, kg/m 3 μ a dynamic viscosity of air, Pa-s

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“…Tren Kenaikan Temperatur (Milan B. Stakic) dan Simulasi Validasi [4] Dengan adanya kesesuaian pada aliran maupun pada grafik distribusi temperatur ini dapat dikatakan bahwa metode komputasi pada simulasi kentang dapat digunakan untuk material teh. Metode komputasi yang sesuai dengan validasi dapat dilihat pada Tabel 1.…”

Section: Gambarunclassified

Analisa Pengeringan Secara Konveksi Butiran Teh pada Fluidized Bed Dryer Menggunakan Computational Fluid Dynamic (CFD)

Utomo¹,

Yanuar²

2017

Rot.

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AbstrakSimulasi numerik perpindahan panas pada teh dilakukan dengan menempatkan material teh pada domain komputasi sebuah aliran eksternal. Penurunan massa pada teh dihitung secara analitik dengan menggunakan persamaan laju penurunan massa. Teh dimodelkan dengan bentuk menyerupai bola setelah dilakukan pelayuan untuk kemudian dikeringkan. Kecepatan masuk aliran udara divariasikan sesuai dengan batas kecepatan minimum dan maksimum fluidisasi pada fluidized bed dryer. Kecepatan yang divariasikan yaitu 3 m/s, 5 m/s, dan 7 m/s. Temperatur masuk aliran udara juga divariasikan berdasarkan temperatur pengeringan teh untuk fluidized bed dryer yaitu 92 0 C, 95 0 C, dan 100 0 C. Model aliran yang digunakan yaitu aliran laminar dengan Re < 10 5 untuk aliran external. Hasil penelitian menunjukkan bahwa perpindahan panas dan perpindahan massa terjadi dengan cepat untuk material teh. Berdasarkan variasi kecepatan aliran udara dan temperatur, maka semakin tinggi kecepatan dan temperatur masuk aliran udara mengakibatkan semakin menurunnya waktu yang dibutuhkan untuk mengurangi kadar air pada teh. Waktu yang digunakan untuk menurunkan kadar air hingga 3% berdasarkan temperatur pada kecepatan 3 m/s secara berurutan adalah 515 s ( Kata kunci: Kadar air, kecepatan aliran masuk, penurunan massa, temperatur pengeringan, waktu pengeringan PendahuluanPerkebunan merupakan salah satu sektor pertanian yang mempunyai peranan cukup penting dalam kegiatan perekonomian Indonesia. Indonesia merupakan salah satu negara dengan hasil perkebunan terbesar di dunia. Sektor ini berperan cukup besar dalam memberi konstribusi penyediaan lapangan kerja dan sumber devisa. Bidang usaha perkebunan terdiri dari usaha budidaya perkebunan dan usaha industri perkebunan. Usaha budidaya perkebunan adalah serangkaian kegiatan pengusahaan tanaman yang meliputi pra tanam, penanaman, pemeliharaan dan pemanenan termasuk perubahan jenis tanaman. Usaha industri perkebunan meliputi industri gula pasir dari tebu, teh hitam, dan teh hijau, kopi, kakao, karet, kelapa sawit, lada serta industri perkebunan lainnya. Teh merupakan minuman yang sudah dikenal dengan luas di Indonesia dan di dunia, sehingga meminum teh merupakan kegiatan yang sering dilakukan masyarakat Indonesia pada pagi hari maupun waktu tertentu.Sebelum teh bisa dinikmati oleh masyarakat, tentu teh tersebut telah melalui berbagai macam proses salah satunya yaitu proses pengeringan. Pengeringan adalah pemisahan sejumlah kecil air atau zat cair dari bahan sehingga mengurangi kandungan atau sisa cairan di dalam zat padat itu sampai suatu nilai yang dikehendaki. Proses pengeringan telah dikenal manusia sejak lama. Melalui proses pengeringan berbagai hasil pertanian, perkebunan, kehutanan dan hasil laut dapat disimpan lama sehingga kehilangan pascapanen yang merugikan petani dapat dihindari.Di Indonesia untuk mengeringkan teh dengan menggunakan mesin pengering masih terbatas pada industri menengah dan industri besar sedangkan untuk industri kecil proses pengeringan masih dilaksanakan dengan cara konvensional atau ...

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Numerical modeling of convective drying of food with spatially dependent transfer coefficient in a turbulent flow field

Cited by 60 publications

References 25 publications

Effect of Process Parameters on Foam Mat Drying Kinetics of Yacon (Smallanthus sonchifolius) and Thin‐Layer Drying Modeling of Experimental Data

Effect of Process Parameters on Foam Mat Drying Kinetics of Yacon (Smallanthus sonchifolius) and Thin‐Layer Drying Modeling of Experimental Data

Three-Dimensional Numerical Modeling of Convective Heat Transfer During Shallow-Depth Forced-Air Drying of Brown Rice Grains

Analisa Pengeringan Secara Konveksi Butiran Teh pada Fluidized Bed Dryer Menggunakan Computational Fluid Dynamic (CFD)

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