Development Of Device For Measuring Thermal Conductivities

Infrared thermal imager can measure the temperature of the measured target,certain thermal parameters can be obtained through the processing of a given algorithm according to internal(or boundary) point’s or multi-points’ temperature information of the measured target,which is called the inverse problem of thermal parameters.Through the temperatures measured by infrared thermal imager and some other known parameters,the thermal physical parameters of the measured target can be estimated by the inversion algorithm,however this problem involves many subjects.The paper aims at the problem of one dimensional heat transfer,the establishment of inverse heat conduction problems occurred in positive platform using transient method,develops a device for measuring thermal conductivity aiming at building materials,industrial materials and composites with regular shape,develops the software system of data acquisition and processing, provides one hand and accurate experimental data for the inversion algorithm.On the basis of knowing the project’s background and research’s significance,the paper fully investigates the research progress of thermal conductivity measurement device at home and abroad.According to the technical requirements of the subject,the transient method is used to detect the temperature information of the material in real time,complete the inversion of thermal conductivity in dynamic measurement and display it.In the process of building the experimental platform,Firstly,constructing the mathematical model,then setting up the corresponding equations to solve the heat conduction coefficient according to the mathematical model,so that the conditions required are known,such as the temperature information of each layer on the side,heat flux,heating power and so on.Making forward experiment platform according to the above mentioned premise condition,There must be technical indicators,an overall design schematic diagra,manufacture of mechanical parts,production of circuit parts,PC software system and so on.In building the software platform,the paper mainly use LabVIEW 2013 software,use the graphical interface for data acquisition of 8 four PT100 temperature acquisition modules,which can be integrated into a whole with the inversionalgorithm,and then achieve the effect of reading the thermal physical parameters directly.Based on the build of the above hardware and software part,we carry out a large number of repeated tests.We use constant temperature tank to filter sensor,to make the consistency of the sensor higher; use thermal imager to screen all kinds of heating film,to make the heat flux more uniform,for the better heating;the sample size is set as350×350×30mm through repeated tests,to meet the heat transfer conditions in semi infinite;the position of punch holes is determined,to make no influence between the holes,to get accurate measurement of the temperature information of each layer.And then a large number of repeated trials are done,in order to ensure the stability and repeatability of the experimental data of the device,to provid a hand and accurate data for the inversion algorithm.