Research Article

Solid-Gas Flow Characteristics of Drilling Bit-Rod Integral Structure

Table 3

Physical parameters of coal and wall.


Coal densitykm·m−31450
Coal Poisson’s ratio0.201
Coal shear modulusPa1.4e9
Coal particle radiusmm1
Steel densitykm·m−37400
Steel Poisson’s ratio0.25
Steel shear modulusPa8.24e10
Coal restitution coefficient0.5
Coal static friction coefficient0.6
Coal rolling friction coefficient0.05
Coal steel restitution coefficient0.5
Coal steel static friction coefficient0.4
Coal steel rolling friction coefficient0.05