The Lineups feature in PIPE-FLO and FLOW OF FLUIDS is typically used to show different operating conditions for a piping system model, but it can also be used to evaluate modifications to the system to understand how the modifications will affect system operation. This functionality is available in both software programs. Here we will use PIPE-FLO for the remainder of the article to describe the use of lineups.
For any device that has a "Lineup Setting", the setting can be changed between lineups. For example, tank levels and pressures, control valve set points and manually set positions, and demand flow rates and pressures can be changed between lineups. Pipelines can also be opened and closed between lineups, and it is this feature that allows the user to use the lineup feature to show the effect of a modification to an existing system.
The "Design Case" lineup is the default lineup that is created when a PIPE-FLO model is created. Additional lineups can be created and device lineup settings changed between lineups. For each new lineup, the lineup settings default to he <Design Case> values.
Version 2009 and Before
Create new lineups by going to the "System" menu, and selecting "Lineups…", then clicking on the "New" button and giving the lineup a name, as shown in Figure 1 and 2.
Figure 1: Creating a new lineup.
Figure 2: Lineups created to show system operation with modifications to expand the system.
Example System Modification
Let's say that the original system in Figure 3 needs to be expanded by adding an additional heat exchanger and flow control valve and transmitter.
The lineups feature can be used to model the modifications. To show the original operation of the system, isolate the modifications in the "Design Case" lineup as shown in Figure 4.
Figure 3: Original system that needs to be expanded.
Figure 4: Modifications modeled but isolated to show the original operation of the system.
Now, to see the effect of adding the expansion of the system, a "System Expansion" lineup is created and the modifications are placed on line by opening the pipe lines to the expansion.
Figure 5: Modifications on-line to show the effects on the original system.
The system can be evaluated to determine if the expansion will have an adverse effect on the overall system. For example, FCV-271 went from 61% to 72% open, but what would happen if a higher flow rate is required to either heat exchanger? To answer that question, an additional lineup is created to show the modifications on line with a higher flow rate required at FCV-271 and the results are shown in Figure 6.
Figure 6: Modifications on line with higher flow required at FCV-271.
The calculated results show that the flow rate at FCV-271 cannot be achieved, and instead of a pressure drop across the valve, there would have to a pressure gain, or energy would have to be added at the control valve. Since this is not physically possible, the results are invalid. Also, there is a "Range" status error for FCV-272, which means that the valve would have to be more than 100% open in order to achieve its flow rate.
But management says "We need that flow rate to increase production. You're the engineer, make it happen!" Now is a good time for another lineup. Two possible solutions are increasing the impeller size or increasing the pump speed. Since these are not lineup settings, a copy of the pump can be placed on the model and the impeller size or speed increased. The pump can be tied into the existing system and the original pump isolated in a new lineup that shows the larger impeller pump on line, as shown in Figure 7.
The calculated results can be evaluated to see the impact of all the modifications on the original system.
Figure 7: Lineup showing the supply pump with a larger impeller installed. Flow can be achieved to both heat exchangers.