Page 43 - Advanced Mine Ventilation

26 Advanced Mine Ventilation

2.6.1 Direct Calculation of Shock Loss
V 2
The shock loss, H S , is a direct function of the velocity head, H V ¼ ; the shock loss.
2g
H S can be expressed as
V 2
H S ¼ K L (2.13)
2g
The velocity head, H V , can be again expressed in familiar units.
H V is in inches of water, and velocity in ft/min.

WV 2
H V ¼
2
5:2ð64:4Þð60Þ
Where V ¼ velocity in ft/min. W ¼ density of air in lbs/ft 3
Hence,

WV 2
H S ¼ K L (2.14)
2
ð1098Þ
where K L is a dimensionless, shock loss factor. The value of K L can be mathematically
calculated.
An example:
Fig. 2.1 shows a rounded bend in an airway of a cross section b d.
Assume:
Deflection angle ¼ q
Bend radius ¼ r
Airway width ¼ b

Figure 2.1 Rounded bend in cross-sectional airway.