Research On Measurement Method For Thermal Conductivity Of Thin Samples Based On TPS Technology

Thermal conductivity,as an important parameter to characterize the heat transfer performance of materials,is widely used in many fields.There are two main methods for measuring the thermal conductivity of materials,steady-state methods and transient-state methods.Transient plane source method(TPS method for short),as an important branch of transient-state methods,has the advantages of short measurement time,high precision and wide range,so it has some advantages in practical application.The measurement method of thermal conductivity of slab samples based on TPS theory(TPS slab method for short)is an important part of TPS method.It is mainly used to measure the slab samples with thermal conductivity greater than 10 W/(m·K).At present,the research on this method is very limited throughout the world.Although there are some instruments based on TPS technology in the domestic market,most of them are not suitable for the measurement of thermal conductivity of slab samples.Based on this,a thermal conductivity measurement system based on TPS method was designed in this thesis,and a mathematical model which can effectively compensates the heat loss of the boundary of TPS slab method was established,which improved the measurement accuracy of the thermal conductivity significantly.The main content of this thesis includes:1.The basic theory and main measuring methods of thermal conductivity were introduced in this part.Then the development status and deficiencies of TPS method were expounded.At last,the research purpose and content of the thesis were put forward.2.This part introduced the derivation process of temperature rise model of the TPS probe.Then the main sources of measurement error of TPS slab method was analyzed,and the theoretical model of TPS slab method was corrected.3.The boundary heat loss is the main source of systematic error in the measurement of thermal conductivity by TPS slab method.Thus a boundary heat loss compensation model was established on the basis of steady heat transfer theory.4.The detail description of the overall design scheme of the thermal conductivity measurement system based on TPS method was given in this part.And then introduced emphatically the designation of the digital adjustable voltage source and the PC software based on Labview5.In this part,the repeatability and relative error of the measurement results of TPS slab method were evaluated by measuring experiments,and the performance of the TPS slab method was studied.At last,the effectiveness of the boundary heat loss compensation model for the TPS slab method was researched6.The overall work of this subject was summarized in this part,and some suggestions for improvement of TPS slab method were put forward.