Germinated Brown Rice Drying by Hot Air Fluidization Technique

Srisang, Naruebodee; Prachayawarakorn, Somkiat; Varanyanond, Warunee; Soponronnarit, Somchart

doi:10.1080/07373937.2010.482691

Cited by 35 publications

(17 citation statements)

References 31 publications

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“…9c. The appearance of multiple fissures along the cross axis of kernel corresponded to that reported by Chungcharoen et al [42] and Srisang et al [3] However, the mathematical model in this research was inadequate for the directional prediction of fissure propagation. Zhu et al [44] reported the propagation of fissure in corn kernel could obtain from mathematical model using fractal analysis.…”

Section: Stresses Inside Gbr Kernelsupporting

confidence: 68%

“…The GABA content of GBR was 2-7 times higher than that of brown rice. [1,2,3] The GABA provides many advantages to consumers such as prohibition of cancer cell proliferation [4] and treatment of the symptom of sleeplessness. [5] Since the GBR has high moisture content, almost 0.50 dry basis (d.b.)…”

Section: Introductionmentioning

confidence: 99%

“…[20,21,22] In this work, the previous stress model developed by Jia et al [20] was used to predict the stresses inside GBR during fluidized bed drying which is frequently operated at the high temperature drying (e.g., 90C or higher) and high air velocity. [3,23] However, the single kernel equations could not predict accurately the changes of temperature, moisture and stresses in the dryer since the amount of drying material in the dryer affected heat and moisture transport. This developed model can be used to control the drying operation precisely.…”

Section: Introductionmentioning

confidence: 99%

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Modeling heat and mass transfer–induced stresses in germinated brown rice kernels during fluidized bed drying

et al. 2015

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A study of stress distribution inside a germinated brown rice (GBR) kernel during drying is important to understand the fissure formation of GBR and hence control the drying process in order to improve the quality of GBR. In this study, a finite element method performed in three dimensions in conjunction with the heat and mass balance of the drying system was developed to describe moisture, temperature and stress distributions inside GBR kernels during fluidized bed drying. The modelling was carried out using the couple of heat and mass transfer and validated with the experimental data at 90-150C.The results of moisture and temperature predictions agreed well with the experiments.During drying, tensile stress occurred at the layers close to surface while compressive stress occurred at the inner portion of a kernel. The tensile and compressive stresses increased to the highest value at about 30 s of drying, corresponding to the highest moisture gradient, and then decreased afterwards. The tensile and compressive stresses were higher at a higher drying temperature. These stress prediction results corresponded Downloaded by [New York University] at 01:36 31 July 2015 2 to the experiments which show more severity of GBR fissuring at higher drying temperatures.

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Section: Stresses Inside Gbr Kernelsupporting

confidence: 68%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Modeling heat and mass transfer–induced stresses in germinated brown rice kernels during fluidized bed drying

et al. 2015

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“…It does not only require a great amount of energy to remove excess moisture in the product but also causes changes in the physical, chemical and mechanical properties of the final product [8][9][10] . Thus, it is very important to carry out the drying process properly to prevent undesirable changes in the grains.…”

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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“…[11][12][13][14][15][16][17] However, the information on vacuum-fluidized bed drying available in the technical literature is very limited. The first studies to employ a vacuum-fluidized bed dryer were carried out in the pharmaceutical industry.…”

Section: Introductionmentioning

confidence: 99%

Influence of Particle Size on Vacuum–Fluidized Bed Drying

et al. 2011

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The effect of particle size on the vacuum-fluidized bed drying process was experimentally studied using pepper seed particles with two distinct diameters. In the constant drying rate period, the small particles demonstrated stronger drying rates resulting from higher mass transfer coefficient values and larger contact area for per unit particle humidity.The experimental results also showed that the falling drying rate period was controlled in the beginning by the particle diameter and later by the effective porosity of the particle. Consequently, in the beginning of the falling drying rate period the small particles presented higher drying rates, whereas toward the end of the period, the large particles, with higher effective porosity, produced stronger drying rates than the small ones.The effects of the vacuum pressure and the superficial gas velocity throughout the process were only observed in the constant drying rate period, whereas the higher operating temperatures enriched the drying rates in both periods.

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Germinated Brown Rice Drying by Hot Air Fluidization Technique

Cited by 35 publications

References 31 publications

Modeling heat and mass transfer–induced stresses in germinated brown rice kernels during fluidized bed drying

Modeling heat and mass transfer–induced stresses in germinated brown rice kernels during fluidized bed drying

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

Influence of Particle Size on Vacuum–Fluidized Bed Drying

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