摘要基于一文无限大平板稳态传热模型开发改进平板式稳态导热仪。设计了一种新型平板保护法导热系数测定仪,由双平板装置和智能控制模块构成。介绍了导热系数微机测控方法,详述了微机测控系统软、硬件的组成,实现了导热系数的自动测量。采用K级热电偶进行温度数据采集,将PID控制技术用于导热系数测定仪的温度控制,有效实现了温度自动跟踪,摆脱了过去人工调节控制稳定温度的弊端。用VB软件编写了仪器的软件程序,实现实时显示测量过程中的冷板、主加热板和防护板的温度,计算得出试件的导热系数。7260
关键词 导热系数 平板导热仪 PID温度控制
毕业设计说明书(论文)外文摘要
Title Method of Plane Table Thermo-conductivity Meter’s Temperature Difference Detection and Control
Abstract
The plane table thermo-conductivity meter was developed and improved based on the steady thermal conductivity model of 1D unlimited large plane-wall. Designed a new plane table thermo-conductivity meter, which is made up of double plate apparatus and intelligent measuring-controlling system. The microcomputer control system for the plane table thermo-conductivity meter has been introduced. The software and hardware has been described. The measurement for thermal conductivity has been realized. The temperature data were gathered by means of the K-level thermocouple. PID technology was used in this instrument, and it solved the problem of manual operation. Compile the program which was designed for the instrument using VB, which included the PID algorithm. It made the circuit communicate with the PC. This part realized the functions such as displaying the temperature of the three plates in real-time and calculating the experimental results.
Keywords Thermal conductivity, The plane table thermo-conductivity meter, PID temperature control
目 次
1 引言 1
1.1 导热系数及其测定方法 1
1.2 国内外导热仪的现状 1
1.3 平板导热仪存在的缺陷与不足 2
1.4 本设计主要研究内容 3
2 双平板保护法导热系数测定仪的测量原理 4
2.1 傅立叶导热定律 4
2.2 一文稳态导热分析 4
2.3 平板法测导热系数的原理 6
2.4 双平板保护法导热系数测定仪的总体设计 8
3 测量控制部分的硬件设计 10
3.1 温度传感器的选择 10
3.2 温度信号的A/D转换 11
3.3 主加热板和护加热板的控制 12
4 控制算法和软件程序设计 14
4.1测控方法及应用 14
4.2 测控模块的程序设计 16
结 论 21
致 谢 22
参 考 文 献 23
1 引言
随着工业发展和能源危机的出现,保温材料的品种不断增多,性能亦不断提高。对作为表征保温材料主要参数的导热系数的测量已成为人们日益关注的工作。测量保温和绝热材料导热系数的双试件保护环式平板法,是国际上通用的标准测试方法。
为了节约能源,很多工业领域、建筑领域都在研究、生产耐热保温材料。导热系数是用来衡量耐热材料的导热特性和保温性能的重要参数,耐热保温材料的性能由材料的导热系数决定。物质的导热系数取决于材料的成分、空隙度、吸水性、含水量、内部结构和热传导时的环境与温度等诸多因素[1]。导热性能的精确测定对于环境工程、建筑工程、工业工程、科研、节能等都有重要意义。 平板导热仪温差检测与控制的方法研究:http://www.youerw.com/wuli/lunwen_5137.html