Experimental Investigation And Simulation On The Combined Heating Measurement Of Conductivity Apparatus With Guarded Plane

The paper makes a comprehensive instruction and analysis to the methods of the conductivity coefficient and educes the instruction of the plate thermal conductivity apparatus. Then the study analyses the shortcomings of the apparatus: or it needs too long time, or its precision is lower. After that, the ways to solve the problems were worked out. The study made the mathematic models of the different heating ways and did a lot of simulations by means of the ANSYS software. Through the simulation it is found out the effects of the different heating ways to the apparatus's capability—including: the constant power heating needs too long time but has the high precision. The constant temperature heating can measure the thermal conductivity coefficient quickly but its precision is lower. The combined heating of the constant power can greatly shorten the time of the measurement. The combined heating of the constant power and constant temperature can conquer the shortcoming of the huge change. The combined heating of the constant temperature and constant power can promote the precision and make the judge to the balance state more easily. After above all, the study introduce the design of the apparatus, including electrical source, controlling circuit, the signal magnifying circuit, A/D conversion circuit and so on. In the end the study design the special program to testify the correctness of the simulation. According to the characteristic of the temperature, including nonlinear characteristic and lag, the design took the arithmetic of fuzzy and PID, and got a good effect. Through the experiments the study found out the different use fields of the different heating ways, and supply different directive ideas for the design of the apparatus.