Research On Material Heat Transfer Performance Testing System

With the rapid green development of the building industry,all kinds of thermal insulation materials are constantly emerging.The traditional thermal insulation materials can not meet the green and efficient development of the construction industry.The light,high efficiency and good insulation performance have become the necessary conditions for the new generation of thermal insulation materials.Thermal conductivity is an important index to measure thermal insulation performance of material.Its measurement is mainly divided into steady state method and non steady state method.The material heat transfer performance testing system of new double plate structure model studied in this paper is based on Fu Liye’s one dimensional steady heat conduction law to measure thermal conductivity,which has wide range and no need for each.Compared with the disadvantages of the existing instrument,such as single function and low automation,the secondary calibration method can accurately and quickly measure the thermal resistance and thermal conductivity of the specimen.The system is mainly divided into hardware design part and software design part,and the calculation formula of the thermal conductivity is obtained by the theoretical basis of the one-dimensional steady heat conduction principle.The hardware part of the system is based on ATmega64 microcontroller,and its hardware circuit mainly includes multi-channel temperature acquisition unit,USB data transmission unit,PID heating control unit,sample tightening device,drive control unit and so on.The software part of the PC using Labwindows/CVI software platform based on C language,the C language and control technology professional tool combination,mainly completes the function of communication module,set permissions set,curve display,data display,menu button control,fuzzy PID algorithm and so on.The slave platform adopts ICCAVR development platform which integrates the editor and Engineering Manager integrated development environment.It mainly realizes the initialization,PWM control,data processing and collection,solenoid valve control,current and voltage signal acquisition,serial port communication and so on.The system also takes slag rock cotton as an example to verify the accuracy of the system.The test error of the instrument is less than 0.5%,which fully meets the design target.