Table 2 Experimental ventilation fan frequency combination scheme (Hz).

From: Experimental study on variable frequency control and air leakage control of multi-fan combination in subway tunnels

Fan combinations

Fan number

Experiment number

1

2

3

4

20

Dual-supply zero-exhaust

1#

6.0

6.9

7.5

8.4

25.2

2#

7.8

8.8

9.8

10.8

26.8

Dual-supply left-side exhaust

1#

7.4

7.4

7.4

7.4

7.4

2#

7.8

7.8

7.8

7.8

7.8

4#

6.5

7.5

8.5

9.5

25.5

Dual-supply right-side exhaust

1#

7.4

7.4

7.4

7.4

7.4

2#

7.8

7.8

7.8

7.8

7.8

3#

6.5

7.5

8.5

9.5

25.5

Dual-supply dual-exhaust

1#

7.4

7.4

7.4

7.4

7.4

2#

7.8

7.8

7.8

7.8

7.8

3#

6.5

7.5

8.5

9.5

25.5

4#

6.5

7.5

8.5

9.5

25.5