Agricultural Research Management Information System

Home
Research Summary
Search
About Us
- ARMIS
- Brochure
Contact Us
Report
User Request
Data Input
Help
- Operation Manual
  - PDF
  - Video
- Program Area & Commodity
We have reached 37600 number of research entries at this moment.

- Logout

Research Detail

Home
Research
Detail

Experimental Evaluation of a Near Equilibrium Simulation Model for Drying of Paddy.

M. Akhtaruzzaman
Department of Farm Power and Machinery,Bangladesh Agricultural University, Mymensingh.

V. K. Jindal
Division of Agricultural and Food Engineering, Asian Institute of Technology, Bangkok, Thailand.

Abstract/ Executive Summary:

In this study experimental validity of a near equilibrium simulation model for drying paddy with ambient air was investigated. The model was based on the simplified assumptions and linear heat and mass balance equations. The drying model predicted the moisture and the temperature changes in the bulk storage of paddy as a result of ambient air flow in the bed. A number of experimental tests were conducted with varying air flow rates and the height of grain beds. Air flow rate was varied from 1.52 to 6.9 m3/min/m2 in 610 mm and 889 mm deep beds. The initial moisture content was also varied in some selected tests. For simulation purpose, the grain bed was divided into 4 or 6 layers depending upon various considerations of the initial moisture content, temperature and grain depth. It was observed that the computed and the experimental results followed similar patterns. In general the predicted moisture contents were higher than the experimental values. This was primarily due to the non-homogenious conditions in the grain bed. This study, however, provided valuable insight into predictions of moisture contents in deep beds of paddy based on the drying simulation model.

Keywords: Drying paddy, Simulation model, Deep bed

Location:

Start Date: 00-01-1978

End Date: 00-03-1978

Program Area: Farm Mechanization

Commodity: Drier

Objectives:

To test the validity of a simulation model for drying paddy with ambient air.

Methodology:

A number of tests were conducted during the months from January to March 1978. The drying test bins consisted of 558.8 mm diameter metal drums to accommodate 609.6 mm and 889.0 mm grain beds. Each bin was provided with an air plenum and an air inlet pipe connecting the bin with holes at three different locations at a given depth for collecting grains for determination of moisture contents. Small tubes were inserted into the bins at different depths to hold the thermocouple wires for recording the grain temperatures inside the bed. A KENT 16 point potentiometer recorder equipped with a timer switch was used to record the air and grain temperatures at an interval of 1 hour, The air flow rate was measured by a vane-type anemometer. The moisture content of paddy was determined by air oven method. Both freshly harvested paddy and remoistened paddy were used for testing. The grains in the test bins were divided into 152.4 mm thick layers, each layer having different initial moisture content and temperature. Air flow rate, initial moisture content and temperature of grains and ambient air conditions during the tests were as follows: Air flow rate: 1.52 ... 6.09 m3/min/m2 Initial moisture content: 14.7 ... 31.9 percent w.b. Initial grain temperature: 21.8…31.1 deg. C. Drybulb temperature: 21.8......35.9 deg. C. Relative humidity : 61.4….99.2 percent. The moisture changes in the experimental drying columns were predicted using mean values of ambient temperature and relative humidity for assumed drying time interval of 3 hours. The grain beds of 610.0 mm and 889.0 mm height were divided into 4 and 6 layers, respectively.

Source of Information: Bangladesh J. Agril. Sci. 16 (1): 41- 47 : 1989

Article Link (Online Journal):

Funding Source:

Total Budget (Tk.) :

Achievement/Findings:

The computed and the experimental drying results followed similar patterns. In general, the predicted drying rates were slower than those experimentally observed in the test bins. This was primarily due to the non-homogeneous conditions in the grain bed. The results of this study, however, provided valuable insight into predictions of moisture contents in the beds of rough rice based on the drying simulation model.

Knowledge Management: Journal