【作者】 李殿华；

【导师】 颜华；

【作者基本信息】 沈阳工业大学 ， 检测技术及自动化装置， 2006， 硕士

【摘要】 近年来,基于声层析成像的温度场检测技术逐渐被应用于工业炉炉内温度的测量中,并得到了快速的发展。本文对层析成像技术进行了简要介绍,对国内外声学高温计的研究现状做了概述,阐述了声学测温的基本原理,制定了声层析成像温度场检测系统的整体方案,确定了采用互相关函数分析的方法对声波飞渡时间进行测量。重点论述了声层析成像温度场检测系统中的关键——声波飞渡时间的测量。 本文分别以白噪声及扫频信号为信号源,采用计算机仿真软件MATLAB,对声波在声发射端和接收端之间的飞渡时间的互相关估计进行了计算机仿真研究。分析比较了信噪比、采样点数、采样频率取不同值时的相关系数曲线,探讨了上述参数对飞行时间互相关测量精度的影响。研究结果表明:采用白噪声或扫频信号作为信号源,应用互相关法测量声波飞渡时间具有很好的抗干扰能力,在采样点数及采样间隔选取适当的时候会得到满意的结果。 本文设计了以白噪声为声源,单片机控制的声学温度场检测系统下位机,实现了声波飞渡时间的互相关测量。对下位机系统进行了实验室测试,测试了在同一温度下声波飞渡时间与声波传播距离的关系,结果表明飞渡时间测量值与传播距离呈线性关系;测试了传播距离一定时声波飞渡时间与室温间的关系,结果表明声波飞渡时间随着室温的升高而减小,符合声速与气体介质温度间关系。下位机初步实验结果表明,所采取的声源和信号处理方可实现声波飞渡时间及声波飞行路径上平均温度的测量。论文还介绍了下位机硬件电路的各部分组成及软件程序流程图。更多还原

【Abstract】 Recently temperature field measurement based on acoustic tomography is applied to measurement of furnace temperature, and developed rapidly. This paper introduce the technology of acoustic tomography, summarize the research of acoustic pyrometer inside and outside, expatiate the keystone of acoustic temperature field measurement, establish the whole scheme of acoustic temperature field measurement, and make sure to adopt the method of correlation function analysis to measure the travel-time of sound wave. This paper mainly discusses the key point of the acoustic temperature field measurement—The travel- time of sound wave.In this paper we separately use White noise and chirp signal as signal source, and apply simulate software MATLAB to research the time delay between the transmitted signal and the received signal. The correlation coefficient curves corresponding to different SNR、 sampling number and sampling interval are analyzed and compared. The influences of these parameters to the precision of correlation measurement are discussed. The results of research indicate that the correlation measurement of delay time has good ability of anti-jamming with suitable sampling number and sampling interval when white noise or chirp signal is used as signal source.With White noise signal source and correlation function analysis, we design the acoustic temperature measurement system controlled by sing chip computer and implement the measurement of the travel-time of sound wave. The sound wave travel-time at different sound travel-distance is measured at a fixed temperature. The test results show that the relationship between the measured sound wave travel-time and the measured sensor’s distance is linearity. The sound wave travel-time at different medium temperature is also measured at a fixed sensor distance. The test results indicate that when gas medium temperature is higher, the sound wave travel-time will be smaller, which accords with the relationship of gas medium temperature and velocity of sound. The preliminary test resultsprove that the signal source and the signal processing method adopted can implement the measurement of the sound travel-time and the average temperature on sound travel-path. The hardware and software design are also given in this paper.更多还原