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•In pipelines of gasses flow functional reliance l = f(De,Re) is valid.It means ,that friction depend from the equivalent roughness and flow regime. | COMPRESSIBLE FLOW FRICTION Friction in gas pipelines Coefficient In pipelines of gasses flow functional reliance l = f(De,Re) is valid.It means ,that friction depend from the equivalent roughness and flow regime. For steel material of gas pipes equivalent roughness De = 0,1 mm . For copper or plastic gas pipes De = 0,0015–0,003 mm only.(see Table) According the Moody chart,5 zones of friction factor is valid: 1) Laminar flow.For laminar flow friction factor is independent of relative roughness,and can be estimated by formula: (1) Where : Re 4000 ,and Re 4000, and 10 4000, and Re e/d >500) surface roughness completely dominates the character of the flow near the wall.( = f ( e/d))From the (5) formula we can find in that case: (6) Equivalent Roughness efor New Pipes Pipe Equivalent Roughness, in mm Riveted steel 0.9 – 9.0 Concrete 0.3 – 3.0 Wood stave 0.18 – 0.9 Cast iron 0.26 Galvanized iron 0.15 Commercial steel or wrought iron 0.045 Drawn tubing 0.0015 Plastic, glass 0.0 (hydraulically smooth) NOTE: Even for hydraulically smooth pipes the friction factor is not zero.That is,there is a head loss in any pipe,no matter how smooth the surface is made.This is a result | COMPRESSIBLE FLOW FRICTION Friction in gas pipelines Coefficient In pipelines of gasses flow functional reliance l = f(De,Re) is valid.It means ,that friction depend from the equivalent roughness and flow regime. For steel material of gas pipes equivalent roughness De = 0,1 mm . For copper or plastic gas pipes De = 0,0015–0,003 mm only.(see Table) According the Moody chart,5 zones of friction factor is valid: 1) Laminar flow.For laminar flow friction factor is independent of relative roughness,and can be estimated by formula: (1) Where : Re 4000 ,and Re < 105,and Re e/d<10) the Blazius formula is fit: (3) In the same III zone when pressure is medium or high and .