Due to the characteristics of the medium transported by medium speed coal mill and the limitations of the inlet pipeline and space

the testing method under cold pure air conditions cannot guarantee the timeliness of the calibration test for the inlet air volume. Under hot conditions

the outlet pipeline of the coal mill was selected as test object for its stable flow field. The dynamic pressure and pulverized coal distribution characteristics of each powder pipe were tested by the equal cross-section grid method. The flow velocity of the air-powder mixture was obtained by the cyclic iterative method. Finally

the inlet air volume of the coal mill was compared and calibrated by the difference between the measured air-powder mixture flow rate

the coal quantity and the design sealing air volume. The practical results show that

on the basis of the same measured original data

the inlet flow rate obtained by the method above is closer to the real value

the accuracy can be improved by about 15percentage points compared with the calculation results with cold conditions method. This method is simple to test and practical

which can effectively improve the timeliness and accuracy of the inlet air volume calibration results of medium-speed coal mill under hot conditions

and at the same time

it also has a certain guiding role in test of the flow rate of powder-containing gas in similar industrial environments.