11 research outputs found

    Effect of Distributed Superficial-Velocity in Deep-Bed Grain Drying

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    This paper deals with influence of velocity field distribution to heat and mass transfer process in deep bed grain dryers. Two-dimensional (2D) models of deep-bed grain dryers were built by considering simultaneously momentum, heat, and mass transfer in the drying air phase. The Navier-Stokes momentum equations are applied to simulate pressure drop and velocity field of the drying airflow. Effect of velocity distribution to the heat and mass transfer coefficient distribution were simulated along the height of grains bed. The dynamic equations are solved numerically by using finite difference method by utilization of alternating direction implicit method, while the momentum equations are solved numerically by utilization of SIMPLE algorithm. The simulation results showed that velocity distribution along the grains bed - 5 cm of bed height - did not so influenced to the heat and mass transfer coefficient. Further, the vector plot of drying air superficial velocity field and contour of pressure distribution along deep bed of grain was simulated

    A Comprehensive Mathematical and Numerical Modelling of Deep Bed Grain Drying

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    This paper deals with comprehensive mathematical and numerical modeling of deep-bed grain drying. In order to build the process model, it is necessary to analyze the transport in both grain and gas phases. Experimental works were carried out for a layer of grain bed in order to validate the models. The models consider momentum, energy, and mass conservation within grain and drying air phase. The twodimensional dynamic equations of energy and mass conservation are solved numerically by finite-difference method (FDM) and utilizing alternating direction implicit algorithm within grain and drying air phase, while momentum conservation are solved by finite difference method by utilizing Semi-Implicit Method for Pressure-Linked Equations (SIMPLE) algorithm. Furthermore, the models will be applied in consideration with developing and designing dryer in order to simulate humidity and temperature profiles of the drying gas together with moisture content and temperature of grain across dryer in term of the dryer performance. The simulations show that the models can be used to predict the dynamic drying characteristic profiles as well as the superficial velocity of drying air phase across dryer

    ALTERNATING DIRECTION IMPLICIT METHOD FOR SOLVING EQUATIONS OF 2-D HETEROGENEOUS MODEL OF DEEP-BED GRAIN DRYING

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    In this paper, numerical studies of two-dimensional mathematical model are presented for deep-bed grain drying based on heat and mass transfer. The two-dimensional dynamic equations are solved numerically by finite difference method with alternating direction implicit algorithm and then applied to simulate humidity and temperature profile of drying gas across dryers together with moisture content and temperature of grain. Line by line algorithm was applied to overcome multidimensional direction. The capabilities of these models were compared with experimental data had been conducted, under variable conditions such as temperature and absolute humidity of drying gas and moisture content of grains. The simulation results show that the two-dimensional dynamic modelling of corn-grain drying can predict the dynamic of drying process

    MODELING AND SIMULATION OF DEEP-BED GRAIN DRYERS

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    This paper concerns with heterogeneous modeling of deepbed grain dryers based on two-phase model by taking into account coupled heat and mass transfer within grains. This model also consider axial mass and heat dispersion in the fluid phase. The dynamictwo-phase equations are solved numerically by finite difference with alternating direction implicit method algorithm, and then applied to simulate humidity and temperature profile of drying gas across dryers together with moisture content and temperature of grains. The capabilities of these models were compared with experimental data obtained from available literatures, under drying conditions such as temperature and absolute humidity of drying gas and moisture content of grains. The simulation results show that the dynamic of corn drying within the bed is well predicted by the two-phase model

    Modelling and Simulation of Momentum, Heat, and Mass Transfer in a Deep-Bed Grain Dryer

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    This article concerns the modelling and simulation of a deep-bed grain dryer in a large diameter-column. Two-dimensional (2D) models of deep-bed grain dryers were built by considering simultaneously momentum, heat, and mass transfer in the drying phase together with coupled heat and mass balance in the grain phase. The dynamic equations are solved numerically by using finite difference method. The momentum equations are applied to simulate pressure drop and velocity field of the drying air across the bed. The mass and heat balance in the two phases determine the profile of temperature and moisture content in both phases. Further, drying rate curves for various temperature of inlet drying gas together with moisture content of grain were simulated. The simulated profiles are in close agreement with experimental data

    NON-LINEAR PARAMETER ESTIMATION OF EMC/ERH CORRELATIONS FOR GRAIN-TYPE PRODUCTS

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    A mathematical prediction of corn sorption isotherm was developed for three-parameter EMC correlation such as Modified-Henderson, Modified-Chung-Pfost, Modified-Oswin, and Modified-Halsey. Moisture sorption experimental data were determined using a dynamic method at temperature 30 oC, 40 oC and water activity range from 0.07 to 0.75. The vapor pressure regulation of air surrounding the grains was adjusted by varying sulfuric acid solution. Non-linear regression algorithms such as Simplex and/or Rosenbrock algorithm were used to fit the measured data to the EMC relations. The generalized correlation coefficient (R2) and the mean relative deviation were in the range of 0.90-0.99 and 2 % - 8 % respectively, in which comparison between predicted and experimental sorption isotherms. From the parameters of correlation, it is possible to get the best equations among them to represent equilibrium moisture content of corn grains. The Modified-Henderson and Modified-Oswin equations give the best model for predicting the adsorption and desorption EMC of corn grain for given range of temperature and water activity

    MODEL HETEROGEN PENGERINGAN BUTIRAN JAGUNG DALAM UNGGUN DIAM

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    Makalah ini mempelajari pemodelan dinamik dan simulasi satu dimensi pengeringan butiran jagung dalam pengering unggun diam (deep-bed) dengan Model Heterogen. Pemodelan pengeringan ini mempertimbangkan peristiwa perpindahan massa dan panas di dalam butiran maupun di udara pengering serta meninjau dispersi aksial di unggun, serta meninjau adanya gradien kadar air dan temperatur dalam butiran jagung. Persamaan-persamaan diferensial parsial yang terbentuk diselesaikan secara simultan dengan metode numerik beda hingga dengan algoritma Alternating Direction Implicit Method. Dalam simulasi ini, dipelajari dinamika pengeringan, baik kelembaban, kadar air maupun temperatur dalam fasa udara pengering maupun fasa butiran. Profil dinamika pengeringan seperti: temperatur dan kelembaban udara keluar pengering serta kadar air rerata butiran jagung sebagai fungsi waktu dibandingkan dengan data eksperimen yang diambil dari literatur yang tersedia untuk mendapatkan parameter-parameter model yang sesuai. Model ini dapat menggambarkan proses pengeringan butiran jagung dalam pengering unggun diam. Modifikasi parameter-parameter model dengan optimasi dilakukan untuk mendapatkan profil karakteristik pengeringan yang lebih mendekati eksperimen

    STUDI EKSPERIMENTAL PENGERINGAN BUTIRAN JAGUNG DALAM PENGERING UNGGUN DIAM

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    This paper concerns with experimental study of deep-bed grain drying in a 0.75 meter diameter dryer-column. The experimental work were carried out in the range of drying conditions such as drying air flow rate (0.08 - 0.12 m/s), drying air temperature (50 - 70 oC), and thickness of bed layer (2.5 - 5 cm). The experimental data presents the dynamic of moisture content of corn grain corresponding with drying condition. The dynamic of moisture content has been analyzed for the variable condition to carry out drying of corn grain. The drying-rate curve was shown at the various drying-air temperatures. Furthermore, the experimental data will be used to validate the developed model. For the dry grain load of 12 kg, we need about 2.25, 2.8 and 4.2 hours of drying time for drying air temperature 70, 60, and 50 oC respectively. The experimental results show that this dryer can be used to accommodate the agricultural grain drying, especially for corn grain

    PEMILIHAN KORELASI KANDUNGAN AIR SETIMBANG (TIGA PARAMETER) UNTUK PRODUK PERTANIAN PADI

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    This paper concerns about selection of equilibrium moisture content-correlation of paddy, based on non-linear parameter estimation. The mathematical prediction of paddy sorption isotherm was developed for three-parameter EMC correlations such as that of Modified-Henderson, Modified-Chung-Pfost, Modified-Oswin, and Modified-Halsey. Moisture sorption experimental data were determined using a dynamic method at temperature 30 oC, 40 oC and water activity range of 0.07 - 0.75. The vapor pressure variations of air surrounding the grains were adjusted by varying sulfuric acid solution. Non-linear regression algorithms such as Simplex and/or Rosenbrock were used to fit the measured data to the EMC correlations. The study found that generalized correlation coefficient (R2) and the mean relative deviation were in the range of 0.85-0.99 and 1 % - 11 % respectively. In view of selection, it will be able to get the best equations among them to represent equilibrium moisture content of paddy grains. Furthermore, the Modified-Henderson correlation gives the best model for predicting the adsorption and desorption EMC for the range of temperature and water activity studied

    Journal of Engineering and Technological Sciences : Volume 47, Nomor 3, July 2015

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    1. Production of Methyl Laurate from Coconut Cream through Fractionation of Methyl Ester J.P. Sitompul, A.N. Istyami, R. Muhtadi, H.W. Lee & H. Rahman 2. Enhancement of Chlorella vulgaris Biomass Cultivated in POME Medium as Biofuel Feedstock under Mixotrophic Conditions M.M. Azimatun Nur & H. Hadiyanto 3. Alkaline Treatment of Oil Palm Frond Fibers by Using Extract of Oil Palm EFB Ash for Better Adhesion toward Polymeric Matrix Warman Fatra, Randi Sanjaya, Zulfansyah, Hari Rionaldo & Zuchra Helwani 4. Partial Hydrogenation of Calophyllum Inophyllum Methyl Esters to Increase the Oxidation Stability Joelianingsih, P. Putra, A.W. Hidayat & R. Fajar 5. Layer-by-Layer Fabrication of High-Performance Broadband Anti-reflection Coatings Coprising Oppositely Charged Nanosheets and Nanoparticles Xin Wu, Jinjuan Xue, Yuming Zhou, Shuaishuai Ma & Man He 6. Modeling of Dynamic Responses in Building Insulation Anna Antonyova, Peter Antony & Endra Joelianto 7. Thermal Energy Storage Optimization in Shopping Center Buildings Totok R. Biyanto, Akhmad F. Alhikami, Gunawan Nugroho, Ridho Hantoro, Ridho Bayuaji, Hudiyo Firmanto, Joko Waluyo & Agus Imam Sonhaji 8. Performance Calculation of Floating Wind Turbine Tension Leg Platform in the South China Sea Hai Feng Wang & You Hua Fa
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