On-line Emissivity Measuring System By Dual-detector Method

Emissivity is an important parameter to describe the characteristic of thermal radiation. It is extensive used in the field of aerospace, non-contact temperature measurement, military stealth and solar energy. On-line measurement of emissivity is significant to the non-contact temperature measurement, but application environment of high temperature and strong vibration makes the measurement more difficult. Therefore, researchers all around the world have developed emissivity detectors based on various kinds of theories with enthusiasm. Measurement system based on dual-detector method has been a new high-performance emissivity detector due to simple structure, high sensitivity, anti-electromagnetic interference and other advantages.Firstly, this thesis introduces the basic law of thermal radiation, and illustrates the fundamental principle of dual-detector method. Determine the infrared thermopile as the radiation energy sensor by comparing with the photon sensitive device. And build a system error factor model through the error analysis of on-line emissivity measurement model based on the dual-detector method. Secondly, according to the measuring principle confirmed system overall scheme that the system consists of three parts, sensor system, electronic circuit and software system. Design the sensor system considering the requirement of application environment. Design the measuring circuit also, including the energy measurement module, the temperature measurement module, CPU module and the power-communication module. And analyze the circuit reliability and accuracy of the system. Meanwhile, introduce the overall flow chart of embedded software, computer display software and data filtering algorithm. Finally, verify the accuracy of the compensation coefficient and test the consistency and repeatability of the measuring system through the test platform.The results of comparison experiments with method of thermal imager and field experiments showed that: measuring system can meet online measurement of emissivity needs in certain conditions and adapt to application environment of high temperature and strong vibration.