A Computing Method for Sand Inrush Quantity through a Borehole in Longde Coal Mine

Table 7

Computing result.

Flow condition	Laminar flow	Effectively smooth flow	Transition region	Rough flow
Velocity (m/s)	5.87 × 10^4	21.14	15.32–17.78	15.43–18.19
Re	2.62 × 10^9	9.44 × 10^5	6.84 × 10^5–7.94 × 10^5	6.89 × 10^5–8.13 × 10^5
Re range	<2300	4000–4.23 × 10^4/2.01 × 10^5	4.23 × 10^4/2.01 × 10^5–2.95 × 10^6/1.44 × 10^7	>2.95 × 10^6/1.44 × 10^7
Verification result	Wrong	Wrong	Right	Wrong