Compressible Gas-Flow in Commercial Pipes

Abstract

The main object has been to facilitate economic design of pipework for compressible flow; it being recollected that the cost of pipework in a given installation may not infrequently exceed the cost of compressor plant. It is found that the conclusion reached by Keenan and Neumann, namely, that compressible, subsonic flow in ‘smooth’ pipes is independent of Mach number and depends upon Reynolds number exactly as for incompressible flow, may be extended to commercial pipes of appreciable wall-surface roughness. While non-adiabatic flow is also examined, attention is mainly given to adiabatic flow; and various devices, tabular, graphical, and nomographical, are proposed to assist rapid estimation of such quantities as flow rate, pressure drop, maximum power transmitting capacity, etc. Encouraging correlation is found to exist between directly measured wall-surface roughness, as represented by the British Standard centre-line average index, and roughness as expressed hydrodynamically by the equation of Colebrook and White. This points to the practicability of predicting the flow characteristics of large pipes, for which flow tests may be difficult until in situ, by surface measurement alone.