Numerical Investigation of Gas Mixture Length of Nitrogen Replacement in Large-Diameter Natural Gas Pipeline without Isolator

Table 1

Simulation cases.

Case	The length of straight pipe, 𝐿1 (m)	Pipe diameter, 𝐷 (mm)	Inlet rate, 𝑣 (m/s)	Inclination angle, 𝜃 (°)	The length of inclined pipe, 𝐿2 (m)
1	50	647.2	3	0	0
2	150	647.2	3	0	0
3	300	647.2	3	0	0
4	400	647.2	3	0	0
5	500	647.2	3	0	0
6	600	647.2	3	0	0
7	700	647.2	3	0	0
8	800	647.2	3	0	0
9	900	647.2	3	0	0
10	1000	647.2	3	0	0
11	600	346.0	3	0	0
12	600	851.2	3	0	0
13	600	1000.2	3	0	0
14	600	647.2	2	0	0
15	600	647.2	4	0	0
16	600	647.2	5	0	0
17	600	647.2	3	10	600
18	600	647.2	3	20	600
19	600	647.2	3	30	600
20	600	647.2	3	40	600