Research Of Acoustic Temperature Field Measurement

Temperature field measurement based on acoustic tomography is a new technology developing in recent years. As a new temperature measurement technology, acoustic method has many advantages such as non-contact, wide temperature range (0～1900℃), large space of measuring object (up to a few decameters) , high-precision, real-time, continuous measurement, easy maintenance and so on. Abroad, it has been matured, and applied to industry furnace for temperature measurement online.This paper briefly introduces the temperature field measurement based on acoustic tomography, summarizes the application present situation and important meaning of acoustic tomography technology at home and abroad, introduces the acoustics temperature measurement basic principle and the acoustic travel-time metering measurement. This paper also introduces the basic philosophy of the acoustic method temperature field reconstruction algorithm and the influence of the acoustic bending effect to the temperature field reconstruction.The measurement of the acoustic travel-time between the sound emitter and receiver is studied with emphasis. The accuracy of acoustic travel-time measurement by directly cross-correlating of the transmitted and received sampling signals is restricted by the sampling interval. This paper used the method of the cross-correlation and the interpolation algorithm to reduce the equivalent sampling interval, and increased the acoustic travel-time measuring accuracy. This method and the detailed simulation experiment result are elaborated in this article.One kind of the exponential reconstruction algorithm based on the pre-optimized transformation is proposed, considering the influence of the acoustic bending effect to the temperature field reconstruction. This paper also gave the detailed simulation results of this temperature field reconstruction algorithm.The acoustic method temperature field examination experiment system and the work process are introduced in detail. The system is tested on the condition of room temperature in lab. The method of the acoustic travel-time measurement using the cross-correlation and interpolation algorithm applies in the actual system. It confirmed that this method is validity. The interpolation method and the exponential reconstruction algorithm based on the pre-optimized transformation are applied in PC software system, and it realized the temperature reconstruction of the measured region. The experimental result indicated that the acoustic method temperature field examination experiment system can well reconstruct the temperature of the measured temperature field, and it confirmed that the acoustic method temperature field examination system is feasible.