Abstract:

ESDU 87027 introduces a Fortran program, provided as an executable file, for a planar network modelled as an assembly of up to 100 straight lengths of pipe. Components that may be modelled are: centrifugal pumps (at steady speed or tripped), valves (closing, opening or constant open), dead ends, air vessels (at pump discharge or on-line) and air inlet/outlet valves (at pump discharge or in-line). Comprehensive guidance is given on the use of the program. The nature of input required is specified carefully, and may include the friction factor and wave speed in the liquid for each pipe or they may be calculated within the program. Steady-state conditions of head and flow are calculated by the program before the transient analysis proceeds, and the onset of column separation or gas release may be predicted, although the behaviour of vapour cavities is not modelled. The use of the program is illustrated by two worked examples, one of valve closure in a three-pipe network, and one of pump trip in a ten-pipe network.