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 5 000~8 000 Hz and the most suitable slant angle of the sound sensor is 20°.