Design of Thermal Conductivity Apparatus Base on Transient-state Radial Cylinder Method

Abstract

Thermal properties i.e. thermal conductivity (k) of agricultural products provide critical information and data for the design and manufacture of equipment and machines for their processing. Literature generally abounds in information on wide and common agricultural products but lack on some locally grown products. The aim of the present study was to design and construct the thermal conductivity apparatus embedded with controlled temperature system and equipped with record system supported with personal computer as data processor. The apparatus designed based on transient-state radial cylinder method, consist of three main parts i.e. measurement chamber, controls panel and data acquisition processor. Measurement chamber was cylinder equipped by radially sixteen node of thermocouple with controlled temperature heater on center cylinder axis. It was placed in temperature controlled box generated by air flow system to eliminate the effect of surrounding temperature outside chamber. Controls panel functioned as link bridge and control unit that connect the measurement chamber to data acquisition processor. It consists of some electronic circuit e.g. analog to digital converter (ADC) to control and acquire data from some thermocouple and sensors. Personal computer as data acquisition processor embedded with software developed with Borland Delphi. Developed software featured with calibrating, recording, calculating mode and displaying all obtained data graphically. Testing procedure was conducted with empty and filled chamber condition to adjust and calibrate data captured by thermocouples and sensors and displayed on personal computer, compared with actual condition. After some adjustment and calibration, all system was well functioned. The outcomes were in good agreements with thermal conductivity (k) of agricultural products reported in the literatures.Keywords—