step 1: set the desired flow rate for each pipe. step 2: click on the stream which you wish to size...
Post on 17-Dec-2015
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Step 2: Click on the stream which you wish to size the pipe. Select Sizing from the menu, then select Pipes
Step 4: Click on Typical sizing for single phase. Then enter the Pipe Schedule. Schedule 40 is used for pipes less than 150 psig.
Step 5: Note the Nominal Dia. If it is in feet, you can change the units to inches under the Engineering Units menu
Insert a control valve in the stream, then enter the Valve flow coefficient (Cv), select Fix valve position, adjust flow rate in the Operating mode, and then enter 50 for the Valve position %. Enter the downstream pressure even if it is not known.
For the upstream node, set the Mode to Fixed Pressure, and enter the pressure at the node. Select Free inlet stream for the inlet and Flow set by UnitOp for the outlet
Enter the outlet pressure for the outlet node, and Flow set by UnitOP for the inlet and Free Outlet stream for the outlet.
Open up the control valve menu and delete the Downstream pressure. Then enter the node number for the Destination ID and Node Pressure for the variable
Click on the pipe, and enter the Method, the Sizing option, the Pipe diameter, Pipe Schedule, Pipe Length, and Pipe Material
Activate the controller, enter the desired set point, the sensor min and max, the proportional band, the control valve ID number, select Reverse for the controller action, and select what is to be measured. Make sure the Engineering Units are set for the units that you desire for the set point.
Start off with a large Integral time for the PID controller and decrease it until a stable value is obtained as quickly as possible.
Assignment: Set up a piping network that can deliver 20 gpm of water at 75 F to each of three floors of a building. One floor is at a 50 ft elevation, the second is at 30 ft, and the third is at 15 ft. Water is available at 60 psia. The outlet pressure at each floor will be at 14.7 psia. Size the piping and control valves under steady state conditions without using the nodes. Once the pipes and valves are sized, begin to optimize the PID tuning one valve at a time. If you try to do it all at once, you will be guaranteed to have problems.
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