Applied Research of Water Jet Technology in Preventing Rock Burst Occurred in Roadways

Table 8

The flow coefficients under different models of nozzles.

Models of nozzles	Flow coefficient
Thin-wall orifice	0.62
Extension stub	0.82
Internal extension stub	0.71
Conical convergence model (contraction angle 13°-14°)	0.95
Conical expansion model (5°-7°)	0.45
Streamline model	0.98