scholarly journals Analisis Sudut Lempar Gabah Pada Mesin Pembersihan Gabah Dengan Media Aliran Udara

2015 ◽  
Vol 8 (1) ◽  
pp. 29-40
Author(s):  
Suhendra Suhendra ◽  
Budi Setiawan
Keyword(s):  
Bulk Density ◽  
Flow Rate ◽  
Air Flow ◽  
Prediction Equation ◽  
Cleaning Process ◽  
Air Flow Rate ◽  
Cleaning Machine ◽  
Flow Through ◽  
Grain Bulk ◽  
The Relationship

Abstrak. Penanganan pasca panen padi merupakan salah satu upaya untuk meningkatkan produksi padi, dengan semaksimal mungkin menekan kehilangan hasil panen. Salah satu faktor yang mempengaruhi kehilangan hasil panen padi adalah proses pembersihan gabah. Berdasarkan hal tersebut, diperlukan suatu upaya untuk mendapatkan proses pembersihan gabah yang optimal dengan cara menganalisis variabel yang berpengaruh pada proses pembersihan gabah. Penelitian ini bertujuan untuk menghasilkan suatu persamaan matematika untuk memprediksi besar sudut lempar gabah, mengetahui hubungan antar variabel yang mempengaruhi proses pembersihan gabah secara mekanis serta untuk mendapatkan variabel yang diperlukan dalam rancang bangun mesin pembersih gabah dengan media pembersih berupa aliran udara. Melalui pendekatan analisis dimensi diperoleh persamaan prediksi sudut lempar gabah (θ) sebagai fungsi dari bulk density gabah (ρ), diameter saluran udara (D), laju aliran udara (V), kapasitas (Kp), diameter gabah (d), kadar air gabah (α) serta jarak saluran udara dan gabah jatuh (l) yaitu :       θ = 0,0661.(ρ.d^2.V/Kp)^0,643 . (dxα/t)^0,0618Hasil validasi persamaan prediksi sudut lempar gabah menunjukkan bahwa hasil prediksi tidak berbeda nyata dengan hasil observasi sehingga persamaan prediksi yang dibuat dapat diterima. Hasil simulasi persamaan prediksi menunjukkan bahwa diameter saluran udara dan jarak saluran udara saat gabah jatuh memiliki pengaruh tetapi tidak signifikan terhadap besarnya sudut lempar gabah, sedangkan laju aliran udara dan kapasitas memiliki pengaruh yang signifikan terhadap besarnya sudut lempar gabah. Throw Angle Analysis of Grain on Grain Cleaning Machine With Air FlowAbstract. Post-harvest handling of rice is one of the efforts to increase rice production, with maximum pressing crop yield loss. One of the factors that influence the loss of the harvest is the process of cleaning of the grain. Based on this, we need an effort to obtain optimal grain cleaning process by analyzing the variables that affect in the grain cleaning process. This research aims to produce a mathematical equation to predict the large grain throwing angle, determine the relationship between the variables that affect in the mechanical cleaning process grain and to obtain the necessary variables in the design of grain cleaning machine with cleaning media in the form of air flow. Through the dimensional analysis approach derived prediction equations throwing grain angle (θ) as a function of grain bulk density (ρ), the diameter of the airways (D), the air flow rate (V), capacity (Kp), grain diameter (d), water content grain (α) and distance airways and grain fall (l), namely:θ = 0,0661.(ρ.d^2.V/Kp)^0,643 . (dxα/t)^0,0618The result of prediction equation from grain throwing angle show that prediction result is not different significant with observation result. Simulation result of prediction equation show that the diameter  of airways and distance airways when grain fall has influence but not significant on the value of  grain throwing angle, whereas the air flow rate and capacity has significant influence on the value of  grain throwing angle.

scholarly journals Effects on the Ventilation of a Two-Storey Building under Different Thermal Conditions

2019 ◽  
Vol 111 ◽  
pp. 02009
Author(s):  
Tim Röder ◽  
Paul Mathis ◽  
Dirk Müller
Keyword(s):  
Flow Rate ◽  
Static Pressure ◽  
Air Flow ◽  
Thermal Conditions ◽  
Volume Flow ◽  
Air Flow Rate ◽  
Static Pressure Difference ◽  
Flow Through ◽  
Flow Pressure ◽  
Storey Building

In this paper it is shown how the air flow rate of decentralized ventilation devices can be affected by a staircase of a two-storey building under different thermal conditions. Since these devices need local fans for supplying the requested volume flow, pressure loads have a significant impact on the delivered volume flow rates. Regarding this, the study comprises two analyses: First, a CFD-model is developed to simulate the ventilation air flow through a simplified staircase. By varying parameters for rooms’ temperature and ventilation direction, the hydrostatic pressure in the staircase is evaluated. The simulations – characterized by high Archimedes numbers – are successfully validated with findings from preliminary work. In a second part, the pressure conditions inside the staircase are referred to outside conditions. Consequently, a static pressure difference at the ventilation device on each storey can be observed. We found that the deliverable volume air flow rate can decrease up to 10 % from the nominal flow rate due to temperature differences between the storeys and outside. Therefore, heat recovery and ventilation effectiveness may also be impaired.

Influence of Operating Parameters on Physicochemical Properties of Fruit Juice Powders Produced by Spray Drying

2014 ◽  
Vol 941-944 ◽  
pp. 1196-1200
Author(s):  
Li Li Zhang ◽  
Chuan Chuan Ma
Keyword(s):  
Moisture Content ◽  
Physicochemical Properties ◽  
Bulk Density ◽  
Air Temperature ◽  
Flow Rate ◽  
Fruit Juice ◽  
Air Flow ◽  
Compressed Air ◽  
Operating Parameters ◽  
Air Flow Rate

This paper investigated the influence of operating parameters such as inlet air temperature, compressed air flow rate, concentration of carrier agent and type of carrier on the physicochemical properties of fruit juice powders produced by spray drying.The results indicated that increasing inlet air temperature resulted in the larger size particles with smoothly spherical appearance, and to lower bulk density and moisture content. The bulk density of powders also decreased with increasing carrier agent concentration, decreasing compressed air flow rate. The higher feed flow rate negatively affected process yield and positively influenced moisture content, and occurring the wall deposition easily. Additionally, the anthocyanin retention mainly depends on the inlet air temperature and type of carrier. Moreover, the novel methods and ideas to this problem in the next studies were presented.

Analytical and Numerical Modeling of Solar Chimney

2017 ◽  
Vol 139 (3) ◽  
Author(s):  
Mohammad Raghib Shakeel ◽  
Jihad Al-Sadah ◽  
Esmail M. A. Mokheimer
Keyword(s):  
Flow Rate ◽  
Volume Flow Rate ◽  
Air Flow ◽  
Incident Radiation ◽  
Analytical Models ◽  
Air Flow Rate ◽  
Solar Chimney ◽  
Trombe Wall ◽  
Flow Through ◽  
Induced Flow

Solar chimney or Trombe wall has been studied numerically and analytically. Analytical results available in the literature overestimate air flow rate by 46–97%. While insulated walls are used in the experiments, there might still be loss from the chimney walls, which is not usually considered in the available analytical models. It is found that the overestimation of air flow rate can be reduced to 3–14% by including heat losses from the glass and wall side of the chimney in the analytical model. The presently developed numerical model is validated against experimental data from literature. The conditions within which the analytical solution can give good approximate results regarding the air volume flow rate have been identified and discussed. We found that the analytical method simulates solar chimneys well for gap widths of up to 0.3 m and incident radiation above 500 W/m2. The present numerical results revealed that the optimum value of chimney gap width that maximizes the induced flow through the chimney is 0.3 m.

A Method for Determining the Volatility of Herbicides

Weed Science ◽  
1975 ◽  
Vol 23 (6) ◽  
pp. 529-532 ◽  
Author(s):  
R. Grover
Keyword(s):  
Flow Rate ◽  
Flow System ◽  
Air Flow ◽  
Butyl Ester ◽  
Air Flow Rate ◽  
Technical Grade ◽  
Time Flow ◽  
Effects Of Temperature ◽  
Dichlorophenoxy Acetic Acid ◽  
The Relationship

The effect of time, flow rate, and temperature on the volatilization of technical grade n-butyl ester of 2,4-D [(2,4-dichlorophenoxy)acetic acid] in a closed air-flow system was evaluated. The amount of ester volatilized was linear with time, at constant temperature and air flow. Volatility increased approximately 8-fold when the temperature was increased from 30 C to 50 C. At 30 C, volatility increased with each doubling of air flow rate from 0.86 nmole/cm2 per hr at 14 L/hr to 1.62 nmole/cm2 per hr at 57.6 L/hr. The effects of temperature, flow rate, and the relationship between vapor pressure and rate of volatilization were also analyzed. The system provided a simple and quantitative method for determining the relative volatilities of both technical and formulated herbicides.

scholarly journals Results of the Experimental Studies of Grain Cleaning with an Air-Spiral Separator

2020 ◽  
Vol 210 ◽  
pp. 10002
Author(s):  
Sergey Shepelev ◽  
Maksim Cheskidov ◽  
Vladimir Chumakov ◽  
Aleksandr Gritsenko ◽  
Natalia Shepeleva
Keyword(s):  
Flow Rate ◽  
Air Flow ◽  
Experimental Studies ◽  
Output Parameter ◽  
Laboratory Studies ◽  
Air Flow Rate ◽  
Working Element ◽  
Product Delivery ◽  
Flow Pressure ◽  
The Relationship

We have developed an air-spiral separator with a screw aspiration channel, which allows us to reduce the air consumption and specific quantity of metal per structure. We have established that the separation process is ensured at an air flow rate V = 7.1…7.9 m/s and the diameter of the working element D = 0.3 m/ To ensure a pressure of 120.7…133.4 Pa in the working element of the separator, the fan should ensure the initial air flow pressure P = 158.7…175.4 Pa. Our laboratory studies have established that the change in the product delivery volume uniformly affects the change in the output parameter at any speed value. We have found that the change in the product delivery volume has a larger effect on the change in the output parameter when the air flow rate increases. The relationship between the product delivery point and the air flow rate is almost linear and uniform.

scholarly journals Model of thermal buoyancy in cavity-ventilated roof constructions

2021 ◽  
pp. 174425912098418
Author(s):  
Toivo Säwén ◽  
Martina Stockhaus ◽  
Carl-Eric Hagentoft ◽  
Nora Schjøth Bunkholt ◽  
Paula Wahlgren
Keyword(s):  
Analytical Model ◽  
Flow Rate ◽  
Numerical Study ◽  
Air Flow ◽  
Wind Pressure ◽  
Air Flow Rate ◽  
Test Set ◽  
Air Cavity ◽  
Thermal Buoyancy ◽  
The Impact

Timber roof constructions are commonly ventilated through an air cavity beneath the roof sheathing in order to remove heat and moisture from the construction. The driving forces for this ventilation are wind pressure and thermal buoyancy. The wind driven ventilation has been studied extensively, while models for predicting buoyant flow are less developed. In the present study, a novel analytical model is presented to predict the air flow caused by thermal buoyancy in a ventilated roof construction. The model provides means to calculate the cavity Rayleigh number for the roof construction, which is then correlated with the air flow rate. The model predictions are compared to the results of an experimental and a numerical study examining the effect of different cavity designs and inclinations on the air flow rate in a ventilated roof subjected to varying heat loads. Over 80 different test set-ups, the analytical model was found to replicate both experimental and numerical results within an acceptable margin. The effect of an increased total roof height, air cavity height and solar heat load for a given construction is an increased air flow rate through the air cavity. On average, the analytical model predicts a 3% higher air flow rate than found in the numerical study, and a 20% lower air flow rate than found in the experimental study, for comparable test set-ups. The model provided can be used to predict the air flow rate in cavities of varying design, and to quantify the impact of suggested roof design changes. The result can be used as a basis for estimating the moisture safety of a roof construction.

scholarly journals Modeling and optimization of radish root extract drying as peroxidase source using spouted bed dryer

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shahrbanoo Hamedi ◽  
M. Mehdi Afsahi ◽  
Ali Riahi-Madvar ◽  
Ali Mohebbi
Keyword(s):  
Kinetic Parameters ◽  
Flow Rate ◽  
Air Flow ◽  
Cost Effective ◽  
Industrial Applications ◽  
Interactive Effects ◽  
Root Extract ◽  
Air Flow Rate ◽  
Spouted Bed ◽  
Radish Root

AbstractThe main advantages of the dried enzymes are the lower cost of storage and longer time of preservation for industrial applications. In this study, the spouted bed dryer was utilized for drying the garden radish (Raphanus sativus L.) root extract as a cost-effective source of the peroxidase enzyme. The response surface methodology (RSM) was used to evaluate the individual and interactive effects of main parameters (the inlet air temperature (T) and the ratio of air flow rate to the minimum spouting air flow rate (Q)) on the residual enzyme activity (REA). The maximum REA of 38.7% was obtained at T = 50 °C and Q = 1.4. To investigate the drying effect on the catalytic activity, the optimum reaction conditions (pH and temperature), as well as kinetic parameters, were investigated for the fresh and dried enzyme extracts (FEE and DEE). The obtained results showed that the optimum pH of DEE was decreased by 12.3% compared to FEE, while the optimum temperature of DEE compared to FEE increased by a factor of 85.7%. Moreover, kinetic parameters, thermal-stability, and shelf life of the enzyme were considerably improved after drying by the spouted bed. Overall, the results confirmed that a spouted bed reactor can be used as a promising method for drying heat-sensitive materials such as peroxidase enzyme.

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