Study On Several Key Technologies Of Thermal Conductivity Coefficient Measuring Instrument

Today, as energy becomes one of the key issues of the world, more and more attention has been paid on energy saving. One of the main ways to save energy is the use of thermal insulation material. The material's thermal insulation property is determined by its Thermal Conductivity Coefficient (TCC). The material with low TCC normally has good heat insulation. And the measurement of TCC plays an important role in the research, development and manufacture of the thermal insulation material. There are mainly two methods to measure the TCC, the steady state method and the transient method. At present, the GHP (Guarded Hot Plate method), which belongs to steady state method, has been widely used. But its three key technologies: the thermal equilibrium, the power compensation and the automatic measurement, which can affect the measurement accuracy and efficiency, have not been well resolved; Meanwhile, the steady state method has some disadvantages such as the fixed measurement time and the narrow measurement range.In this study, the GHP thermal conductivity coefficient measuring instrument has been improved with the use of Labview software, optimization algorithm and model correction, and its key technologies of the thermal equilibrium, the power compensation and the automatic measurement have been intensively investigated; Besides, the transient thermal conductivity coefficient measuring instrument based on the TPS(Transient Plane Source technique) has been developed with attentions paid to the TPS senor design and the measuring circuit.The main work of this thesis is as follows:1. The basic concepts and measurement methods of TCC was introduced, the status and problem of GPH and TPS thermal conductivity coefficient measuring instrument was described.2. The measurement principle of GPH and TPS thermal conductivity coefficient measuring instrument was described.3. The correction methods of thermal equilibrium and power compensation for the GHP thermal conductivity coefficient measuring instrument system were researched, and that effectively improved the instrument's accuracy. 4. Corresponding methods to determinate the system steady state of GHP thermal conductivity coefficient measuring instrument was provided, which greatly increased its measuring efficiency and the degree of automation.5. The complete set of measure and control software for GHP thermal conductivity coefficient measuring instrument system was designed, it can do the jobs of Data Acquisition and Processing, parameters controlling, measurement report generating and so on.6. The TPS thermal conductivity coefficient measuring instrument and its whole hardware are initially developed, then the TPS senor and the measuring and controlling circuit were designed, finally its software was developed and gave some data processing methods.7. Some experiments are carried out. The accuracy and feasibility of thermal equilibrium compensation method, power correction method and automatic measurement algorithm of GHP thermal conductivity coefficient measuring instrument were tested and verified; the TPS senor and the measuring and controlling circuit of TPS thermal conductivity coefficient measuring instrument were tested, some measure results of kinds of material's thermal conductivity coefficient were gave.8. The problems and the further research direction of this paper are pointed out.