Development Of A Device For Measuring Thermal Conductivity Of Materials Heated By Saturated Water At A Constant Temperature

As we known,the thermal conductivity is one of the key indicators of material thermal physical properties,and its accurate and efficient measurement is of great significance for the research and application of thermal insulation materials in the chemical,aerospace and construction industries.The GHP method is the criteria method for measuring thermal conductivity at domestic and international,but,the widely used GHP method based on constant power heating still suffers from slow testing speed and difficulty in meeting high accuracy measurements.So,the study of thermal conductivity measurement devices based on this method is of great importance to change the status quo of thermal conductivity measurement technology at home and abroad.This article aims to develop a new thermal conductivity measuring device based on constant temperature heating of saturated water,which can realize high-efficiency and high-precision measurement of thermal insulation materials in the temperature range of 100-300℃.The main tasks completed in this paper are as follows:1.Designed a thermal conductivity measurement device based on saturated water constant temperature heating,with novel design of main heating surface,cooling surface and side insulation design.With the support of.Xiangtan Instrument Company,the experimental platform was set up,and several groups of measurement experiments were carried out on the standard reference plate of insulation material with the newly developed measuring device,and the measurement experiment was compared with a high precision guarded hot plate thermal conductivity instrument.The experimental results show that in the temperature measurement range of 100 ～ 300℃,the accuracy of the newly developed measuring device is ±1.5%,the repeatability is within ±2%,and the measuring time is more than 60% shorter than the widely used constant power heating method heat conduction instrument.2.In view of the shortcomings of the long test time of the guarded hot plate thermal conductivity meter,which is widely used in constant power heating,a lot of simulation studies are conducted on different heating modes by using simulation software,so as to find the influence of different heating modes on the test time of the guarded hot plate thermal conductivity meter.The simulation results show that the combined heating method can shorten the test time,and the constant temperature method can shorten the test time best.