An existing closed-loop cooling system is to be modeled. The
flow path includes parallel pumps, parallel heat exchangers,
and multiple parallel cooling loads. The fluid is water, nominally
at 60 degrees Fahrenheit and 50 PSIA. The pump suction pressure
(at the connection from a surge tank) is approximately 20 PSIA.
combined supply header is 4 inch schedule 40. This header then
supplies two 2 inch lines as well as a 1 inch line. The question
is whether flow velocities throughout the system are maintained
less than the desired limit of 8 feet per second (this limit
being an arbitrary design limit based on the sound characteristics
of the system).
The first step is to build the network layout and define all
system hardware. Next the fluid information is entered. Finally,
the pressure at the suction of the pumps is defined. The system
will then solve for all system flow rates, pressures, and velocities.
By displaying velocities, it is easily seen whether the desired
criteria is met. If not, "what if" scenarios can be
readily analyzed to determine the best way to meet the desired
In the above case, nominal conditions were modeled. Further
analysis could include off-normal conditions and casualty situations
(e.g., failure of one pump, loss of surge tank level, et cetera).