Because of the short distance between the hot-cold air mixed segment and the measuring cross section

the hot air was unable to fully mixed with the cold air

so the stability and accuracy of measurement for primary air at inlet of the coal mill was relatively low.Through numerical simulation

the guide blade was installed in primary air pipe where hot and cold air mixed together

to increase the penetration depth of the cold air.The temperature difference of the measured cross section dropped from 166 ℃ to 22 ℃

and the variation range of speed on it decreased from 13-25.8 m/s to 20-22 m/s.After the flow mixed device was installed

the hot and cold air were fully mixed

effectively improving the uniformity of speed and temperature distribution on the measuring cross section.The air flow measurement coefficient was stable and the accuracy was improved obviously.