Network and pipe flow
The figure on the left shows a simple Flowmaster network of a foul water pumping
station, pumping to a treatment plant 10km away. The usual starting point
for this and most hydraulic studies is to carry out a series of steady state
analyses modelling the various flow scenarios. Flow systems are not always
steady state for instance when a pump starts or a valve opens the flow will
change and the system has a transient response. However for may systems the
transient response is not significant and so can be ignored.
The theory of flow in pipes and open channels is well documented. For a simple
pipe system the analysis is relatively straightforward and the equations can
be easily solved using a spreadsheet. For more complex systems such as networks
a number of simultaneous equations need to be solved making a solution more
difficult to find. Today there are a number of software tools designed to
solve these flow problems such Flowmaster and Wanda.
A flow analysis can only be as accurate as the model that is used. Errors
usually occur in modelling fittings such as bends, tees, non-standard components
and in determining appropriate roughness factors. Getting the model right
and knowing that the results are correct comes with experience.
Analysing the behaviour of pre designed systems may only confirm what you
already know. At Fluid Mechanics we have the necessary experience to offer
a lot more. For new systems we can assist in the design process, providing
recommendations on system design and control, optimise pipe and fitting sizing,
provide performance specifications for pumps and valves and assist in supplier
selection. For existing systems we can assist in identification of problems
and recommend solutions or improvements, for example how energy consumption
can be reduced.