A fuel distribution terminal must be modeled to facilitate future
modifications to meet EPA requirements. The fuel mixture changes
with season, with the winter mixture being the most limiting
(from a fluid flow perspective). The fuel is stored in a vented
tank, with a minimum tank level of 8.2 feet.
supply piping to two parallel pumps is 10 inch. The pump discharge
header is 8 inch, with the diameter ultimately reducing to 4
inch at the individual discharge stations.
operation is to run one pump when one or two filling stations
are in use and both pumps when three or four stations are in
use. The minimum flow requirement to each station is 1000 GPM.
The first question is whether the current configuration meets
the desired criteria.
The first step is to build the network. Since the individual
filling station supply lines are identical, only one need be
built; the remaining three lines can simply be copies of the
fluid is then specified (as a user-specified custom fluid with
the known properties). Known flow information includes the pressures
at the inlet tank and the discharge pressures at the filling
stations. The system then solves for the flow rates.
Unfortunately this problem did not meet the specified criteria.
With DF DesigNet, however, it is easy to identify why and also
identify possible solutions. In this case, simply displaying
differential pressures identifies where the vast majority of
the pump discharge head is lost. A simply change to the pump
discharge header size will alleviate the problem.