# Selection of the diameter of the local mine ventilation duct(4)

2. Application
2.1 Actual case
The air volume Q of the excavation face of a mine is 3m3/s, the wind resistance of the mine ventilation duct is 0. 0045(N·s2)/m4, the ventilation power price e is 0. 8CNY/kwh; the price of the 800mm diameter mine ventilation duct is 650 CNY/pcs, the price of mine ventilation duct with a diameter of 1000mm is 850 CNY/pcs, so take b = 65 CNY/m; the cost coefficient k of the installation and maintenance of the duct is 0.3; the motor transmission efficiency is 0.95, and the operating point efficiency of the local fan is 80%. Find the economic diameter of the mine ventilation fan.

According to formula (11), the economic diameter of the mine ventilation duct can be calculated as:

2.2 Economical diameter mine ventilation duct for different air demands

According to formula (11) and other parameters in the actual case, calculate the diameter of economic mine ventilation duct with different air volume. See Table 4.

Table 4    Relationship between different air volumes required for working face and diameter of economical ventilation duct

 Air volume required for working face/( m3· s-1) 0.5 1 1.5 2 2.5 3 4 5 Economic duct diameter/mm 0.3627 0.513 0.6283 0.7255 0.8111 0.8886 1.0261 1.1472

From Table 4, it can be concluded that the diameter of the economical ventilation duct is basically larger than that of the common ventilation duct. The use of the economical diameter ventilationduct is beneficial to increase the air volume of the working face, reduce energy consumption, and reduce ventilation costs.

3. Conclusion

3.1 When the mine ventilation duct is used for local ventilation, the diameter of the ventilation duct is related to the purchase cost of the mine ventilation duct, the electricity cost of the mine ventilation duct, and the installation and maintenance cost of the mine ventilation duct. There is an optimal economic mine ventilation duct diameter with the lowest total cost.

3.2 When using the mine ventilation duct for local ventilation, according to the air volume required by the working face, the economic diameter ventilation duct is used to achieve the lowest total cost of local ventilation, and the ventilation effect is good.

3.3 If the section of the roadway allows, and the purchase cost of the mine ventilation duct is low, the diameter of the economic ventilation duct should be selected as much as possible to achieve the purpose of large air volume, small resistance and low ventilation cost on the working face.

Post time: Jul-07-2022

• #### Whatsapp

##### whatsapp
0086 15828151260