The Study On Key Technology Of Acoustic Pyrometer

The measurement temperature field of internal furnace for online real-time control, safe and stable operation, diagnostics and optimize the combustion process of the boiler has extremely important practical significance. However, the large size of temperature field, the poor environment characteristics and transient changes and random turbulence in the furnace combustion process, which make the online real-time measurement of furnace gas temperature difficult. The acoustic method of gas temperature detection technology is a new type of non-contact furnace gas temperature measurement method, with fast, accurate, wide measurement range, real-time continuous measurement as well as easy maintenance characteristics, which make it able competent the task of boiler gas temperature measurement in scientific research and industrial production, and the measurement results for optimized combustion and reduce pollution, guarantee the equipment safe and efficient operation, and furnace optimization design and so on has an important guiding significance.First, this paper study the principle of the acoustic method of gas temperature detection technology, and analyze its theoretical basis, and eventually obtained a function of temperature and speed of sound.Secondly, a circuit system was designed, which hardware system including the analog circuit and the digital circuit was described in detail. Besides, the article introduce the mechanical structure and installation of the cooling system, analyze the cooling system’s working mechanism, describe the influence of acoustic duct and give the modified method.Again, the article research of the delay estimation algorithm based on the cross-correlation theory, analyze the theory and calculation process of algorithm with the weighting function as the core of the generalized cross correlation delay estimation in depth. To improve the precision of measuring the time-of-flight, interpolation methods were introduced based on the cross-correlation theory, moreover study the possibility to improve the signal to noise ratio used spectral subtraction, which commonly used in voice enhancement field. Meanwhile, described and analyze of related software design.Finally, a series of related experiments was carried out in the laboratory, which makes the relevant parameters of acoustic measurement system, and the same time analyze potential measurement errors and put forward the solutions. Interpolation and spectral subtraction were applied on the key issues of the system to improve the measurement precision, and the experimental results show that the system measurement precision is better than using generalized cross-correlation algorithm.