Tools › Fluids and Heat Transfer › Pipe Flow

Pipe Flow

3 tools in the Fluids and Heat Transfer area.

Pipe Flow

Incompressible flow of a liquid in a pipe: Reynolds number and regime, the Darcy friction factor by the Colebrook equation (iterated to 1e-12) with the Swamee–Jain and Haaland explicit values beside it and 64/Re in laminar flow, major and minor head losses (fittings by the Crane TP-410 K = n f_T method or a fixed K, entered K or equivalent length), pressure drop, total dynamic head with the elevation change, hydraulic and pump power; or the flow for a given head loss (with White's explicit solution beside the iteration), or the diameter for a given flow and head loss (with the Swamee–Jain explicit formula). Water properties come from the NIST WebBook table at the entered temperature, any other liquid from an entered density and viscosity; standard Schedule 40 and 80 inside diameters and the Moody roughness values are built in. A pasted pump curve gives the operating point against the system curve and the NPSH available. The default case is Moody's 1944 chart illustration, 200 ft of 6-in asphalted cast-iron pipe at 6 ft/s (White, Fluid Mechanics, Example 6.7): head loss about 4.5 ft, pressure drop about 280 lbf/ft². The HVAC area's Hydronic Pipe Sizing tool covers multi-segment water circuits by the usual sizing limits.

1 worked example reproduced, listed on the tool page.

Water Hammer and Pipe Expansion

Two pipe-line checks. Surge: the pressure-wave speed in a liquid-filled pipe from the fluid bulk modulus and the pipe elasticity (thin or thick wall, the three axial-restraint cases, entrained air), the Joukowsky pressure rise and the critical closure time 2L/a, the slow-closure estimates (rigid column, Michaud, Allievi), the method of characteristics for a reservoir, pipe and valve with Darcy friction (head at the valve against time, maximum and minimum head envelope along the pipe, linear or entered closure curve), a pump-trip check by rigid column (downsurge, column separation, check-valve return surge), surge-tank and air-chamber sizing by the rigid-column closed forms, and the surge pressure against the pipe rating and hoop allowable. Thermal expansion: the free expansion of a run with the MIL-HDBK-1003/8A table beside it, the anchor force and stress of a fully restrained line, guided-cantilever L-bend, Z-bend and U-loop sizes, the ASME B31.3 flexibility criterion, expansion-joint travel and support spacing. Water properties from the IAPWS-IF97 library. Defaults are illustrative: a 1,000 m 12-in steel main at 2 m/s closed in 1 s under 50 m of head, and a 100 ft steel steam line heated 300 °F.

1 worked example reproduced, listed on the tool page.

Flow Measurement: Orifices, Nozzles, Weirs and Flumes

1 worked example reproduced, listed on the tool page.

Other Fluids and Heat Transfer sections

Pumps and Fans · Compressible Flow · Conduction · Convection · Radiation · Heat Exchangers · Thermodynamic Cycles · Fluid Properties