CFD-DEM Simulation of Reverse Circulation Pneumatic Cuttings Removal during Coal Seam Drilling

Table 1

Settings of simulation parameters.

Item	Parameter	Unit	Value
Drill cuttings	Poisson ratio	—	0.3
	Shear modulus	Pa	1 × 10^9
	Density	kg/m^3	1400
Drill pipe	Poisson ratio	—	0.29
	Shear modulus	Pa	7.9 × 10^10
	Density	kg/m^3	7800
Contact of cuttings and cuttings	Contact model	—	Hertz-mindlin
	Recovery coefficient	—	0.5
	Static friction coefficient	—	0.6
	Rolling friction coefficient	—	0.05
Contact of drill cuttings and drill pipe inner wall	Contact model	—	Hertz-mindlin
	Recovery coefficient	—	0.5
	Static friction coefficient	—	0.4
	Rolling friction coefficient	—	0.05
Atmosphere	Density	kg/m^3	1.225
	Dynamic viscosity	kg/(m·s)	1.7894 × 10^−5