Research Article
Solid-Gas Flow Characteristics of Drilling Bit-Rod Integral Structure
Table 3
Physical parameters of coal and wall.
| | Parameter | Unit | Value |
| | Coal density | km·m−3 | 1450 | | Coal Poisson’s ratio | — | 0.201 | | Coal shear modulus | Pa | 1.4e9 | | Coal particle radius | mm | 1 | | Steel density | km·m−3 | 7400 | | Steel Poisson’s ratio | — | 0.25 | | Steel shear modulus | Pa | 8.24e10 | | Coal restitution coefficient | — | 0.5 | | Coal static friction coefficient | — | 0.6 | | Coal rolling friction coefficient | — | 0.05 | | Coal steel restitution coefficient | — | 0.5 | | Coal steel static friction coefficient | — | 0.4 | | Coal steel rolling friction coefficient | — | 0.05 |
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