在不影响烟气管道原有流场的前提下,基于声学技术对电站锅炉烟气流速进行了非接触式实验测量.实验采用扫频信号作为信号源,声源和声音传感器分别布置在流道上下2个端面,倾斜一定角度并呈一条直线;根据时差法求气体流速原理,分别运用基本互相关算法和基于相位变换(PHAT)加权广义互相关算法对声波飞渡时间进行测量;比较不同算法和不同倾斜角的测量结果,找到最合适的倾斜角度,并与涡街流量计测得的结果进行比较,验证其可行性.结果表明:非接触式声波法可以在不影响管道流动的情况下准确测得烟气流速;PHAT加权广义互相关算法在测量准确性和灵敏度方面明显优于基本互相关算法;非接触式声波法声源扫频频率5000～8000 Hz、倾斜角20°时测量结果最准确,精确度高.%The non-contact measurement of flue gas velocity for utility boilers can be realized by using acoustic technology. In this experiment, the swept signal was used as the signal source, the sound source and sound sensors were arranged at the up and down end faces of the flow channel respectively, with a certain titling angle and in a straight line. On the basis of the time-difference method, the sound travel time was measured by the basic cross correlation algorithm and the phase transformation (PHAT) weighted generalized cross correlation algorithm respectively. The results of different algorithms and different slant angles were compared to find the most suitable slant angle, and the gas velocity measured by the acoustic technology were also compared with that measured by the vortex flowmeter, to verify its feasibility. The results show that the acoustic method can accurately measure the flue gas velocity without affecting the flow field in the pipeline. The PHAT weighted generalized cross correlation algorithm is superior to the basic cross correlation algorithm in terms of measurement accuracy and sensitivity. The optimal sweep frequency of the sound signal is 5000～8000 Hz and the most suitable slant angle of the sound sensor is 20°.
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