Piping System Model
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This page is for SysCAD 9.3 Build 136.
Contents
General Description
The Piping System Model is used in dynamic projects with Transfer mode. It allows the user emulate a full piping system, including Pumps, Valves, Pipe lengths, etc in a single Piping System model. The user specifies the number and type of subunits in the piping system and can configure each subunit individually. The user must configure the individual subunits within the Piping System Model so that they comprise a reasonable system.
The piping system model calculates the pressure drop across each subunit, and hence across the entire system. If required it will also calculate the estimated flow through the system, based on the calculated pressure drop.
The available subunits in a Piping System Model are:
 Head  Elevation Head  the head due to the height of the liquid at the start of the piping system;
 Pipe  pipe lengths and fittings can be included  the pressure drop in the pipe due to change of height, friction losses, etc. will be calculated;
 Pump2  pressure boost provided by a pump; and
 Valve2  pressure drop provided by a valve.
Notes
 The Pump and the Valve have control settings that the user may dynamically change. These settings will change the calculated pressure drop of the system.
 The Piping System Model will NOT automatically adjust the flow, but can be set to calculate the estimated flow through the system. This estimate can then be used to set the actual flow in the system, if required.
 The Piping System Model is designed to emulate an entire piping length, without any split flows.
 The Piping System Model requires a single input and a single output and will not operate unless both of these streams are connected. The physical location of the connections is not important  the user may connect the streams to any position on the drawing.
Inputs and Outputs
Label  Required Optional 
Input Output 
Number of Connections  Description  
Min  Max.  
Input  Required  In  1  1  Input stream to Piping System Model. 
Output  Required  Out  1  1  Output stream from Piping System Model. 
Model Theory
For Valve and Pump theory please see:
 Valve Theory and
 Pump Theory.
Data Sections
The default access window consists of the following sections:
 PipingSystem tab  Allows the user to insert subunits and displays the calculated results.
 Control tab  Allows the user to set any valve positions and Pump speeds.
 Settings tab  Allows the user to specify the subunit methods and enter the required data.
 Info tab  contains general settings for the unit and allows the user to include documentation about the unit and create Hyperlinks to external documents.
 Links tab, contains a summary table for all the input and output streams.
 Audit tab  contains summary information required for Mass and Energy balance. See Model Examples for enthalpy calculation Examples.
Piping System Page
Unit Type: PipingSystem  The first tab page in the access window will have this name.
Tag / Symbol

Input / Calc

Description/Calculated Variables

Options  
On  Tick Box  This allows the user to disable the unit. If the unit is Off then the pressure drop across the unit = 0. 
Options (Flow Estimate Calculations)  
FlowEstimateMethod  None  The user does not wish to calculate the estimated of the flow through the unit. The pressure drop WILL be calculated. 
Simple  The flow through the unit will be calculated with no time delays or transient effects. This is useful for short piping systems.  
User Damping  The flow through the unit will be calculated with a time delay, or transient effect. The user may set the fraction of damping required.  
Length Damping  The flow through the unit will be calculated with a time delay, or transient effect, based on the length of the piping system. This is useful where the user wishes to emulate a long pipeline so that a change in feed pressure does produce an instantaneous flow change in the pipe system.  
DampingRate  Input  Visible if User Damping is the Flow Estimate Method selected. The required amount of damping on the estimated flow. 0% represents no damping (changes are instantaneous  so equal to using Simple), and 99% represents large damping. 
SpecifyTargetP  Tick Box  The user may specify a target outlet pressure from the system. If this is NOT enabled, then the outlet pressure is assumed to be the system inlet pressure. This is not visible if the user selects None as the Flow Estimate Method. 
TargetExitP  Input  If SpecifyTargetP is enabled then this field is visible and the user may set the required outlet presusre from the piping system. 
Subunit Selection  
SegmentCount  Input  The user may define the number of subunits in the Piping System Model. For example, if a system consists of a Valve, Pump, Valve and pipe then the number of subunits, or segments = 4. 
ReNumber  Button  This renumbers all of the subunits so that they are all in ascending order. 
Segment Specification  
Type  List  The user may choose any of the subunits that are available, i.e. Head, Pipe, Valve or Pump. 
Insert  Button  The user may insert a new subunit above the current subunit. This will automatically increase the Segment Count. The default subunit that is inserted is a Pipe, but the user may change this by selecting any of the available subunits from the drop down list. 
Remove  Button  The user may remove the subunit from the Piping System Model. This will automatically decrease the Segment Count. 
Up  Button  The user may move the current subunit up in the order of subunits. The subunit number will NOT change, i.e. Pipe3 can be moved above Pipe1. The user may click on the ReNumber button to automatically number the subunits in ascending order. 
Down  Button  The user may move the current subunit down the order of subunits. The subunit number will NOT change, i.e. Pipe1 can be moved below Pipe2. The user may click on the ReNumber button to automatically number the subunits in ascending order. 
Results  
Overview  
Feed.Qm  Display  The mass flow through the Piping System Model. 
Feed.T  Display  The inlet temperature to the Piping System Model. 
Feed.P  Display  The inlet pressure to the Piping System Model. 
Subunit(i).Po  Calc  The pressure from subunit(i), where this could be Head, Valve, Pump or Pipe. The pressure from each subunit will be displayed. 
Prod.P  Calc  The exit pressure from the Piping System Model. 
Prod.T  Calc  The exit temperature from the Piping System Model. 
Totals  
Subunit(i).dP  Calc  The pressure change across subunit(i), where this could be Head, Valve, Pump or Pipe. The pressure change across each subunit will be displayed. 
dP  Calc  The total pressure change across the Piping System Model. 
PDrop  Calc  The pressure drop across the entire Piping System Model. 
PBoost  Calc  The pressure boost across the entire Piping System Model. 
Closed  Tick Box  If this is True, then a subunit, either a Valve or Pump, is set to 0% and is the flow estimate = 0. 
Head  Calc  The calculated Head from the Piping System Model. 
HeightChange  Calc  The calculated change in Height across the Piping System Model (ve indicates a drop from Feed to Product) 
Relative Heights  
Feed  Calc  The relative height of the feed to the Piping System Model. 
Subunit(i).Out  Calc  The relative height of subunit(i), where subunit can be Head or Pipe. All Head and Pipe subunits will be displayed. 
Prod  Calc  The relative height of the product of the Piping System Model. 
Flow Estimate These fields are only visible if the user has selected a Flow Estimate method.  
Qm  Display  The actual mass flow through the Piping System Model. 
QmEstState  Display  The state of the Piping System Model estimate. This lets the user know what state the model is in, i.e. OK, No Flow, subunits closed, etc. 
ExtraTarget.dP  Calc  The extra pressure drop required IF the user has specified a Target Exit Pressure from the unit. 
TotalK  Calc  The calculated resistance, or loss coefficient value, K, of the Piping System Model. 
TotalHead.dP  Calc  The total pressure change across the Piping System Model. 
DiamUsed  Calc  The piping diameter used to calculate the velocity and estimated flow through the Piping System Model. 
VelocityEst  Calc  The estimated velocity in the Piping System Model. 
QmEst  Calc  The estimated mass flow rate through the Piping System Model. 
QvEst  Calc  The estimated volumetric flow rate through the Piping System Model. 
PrevVelEst  Calc  The velocity in the Piping System Model estimated in the previous iteration. (This is only useful if Damping is used.) 
Control
If the user selected either a Pump or a Valve as one of the subunits and a controlled mode for either of these, then this tab will allow these units to be controlled.
Please see the relevant subunit for a description of the fields:
Settings
The user must configure each subunit that is specified on the first tab.
Please see Valve Settings and Pump Settings for the configuration of the Valves and Pumps.
The settings for Heads and Pipes are described below.
Symbol / Tag

Input / Calc

Description/Calculated Variables

Head  
On  Tick Box  This allows the user to disable the Head. If the Head is Off then Head = 0. 
EquipID  Input  This field is optional. The user may type in an unique ID for this, example Head Tank. 
Height / H  Input  The actual Elevation Head required. This calculates the pressure boost due to elevation as material enters the Piping System. 
Pipe  
On  Tick Box  This allows the user to disable the Pipe. If the Pipe is Off then pressure drop across the pipe = 0. 
EquipID  Input  This field is optional. The user may type in an unique ID for the Pipe. 
OpType  Fixed dP  The user specifies a fixed pressure change across the Pipe. This will be independent of flow. 
Fixed Drop  The user specifies a fixed pressure drop across the Pipe. This will be independent of flow.  
Fixed Boost  The user specifies a fixed pressure boost across the Pipe. This will be independent of flow.  
Darcy  Use the Darcy equation to calculate pressure drop. With this method pressure drop is a function of flow.  
DeltaHeight / dH  Input  The required height difference between the pipe entry and exit. A negative values indicates that the exit is lower than the entry. 
Fixed dP Fixed Drop and Fixed Boost  The following field is visible for these three modes.  
Fixed.dP/Drop/Boost  Input  The required pressure change, drop or boost (depending on the mode selected) across the Pipe. 
Darcy The following fields are visible with this mode.  
Diameter / Diam  Input  The required internal pipe diameter. 
ScaleBuildup / Scale  Input  The required scale build up thickness in the pipe. Note, this values will be multiplied by 2 and then used to decrease the actual internal diameter of the Pipe. 
MinorK  Input  The K value for any fittings on the pipe. 
KMethod  User Pipe K  The user specifies a K value for the pipeline. 
Length and Friction F  The user specifies the pipe length and a friction factor. SysCAD will then calculate the equivalent K value.  
Length, Colebrook FricF  The user specifies the pipe length, Viscosity and roughness. SysCAD will then calculate the friction factor using the Colebrook equation.  
Length, Churchill FricF  The user specifies the pipe length, Viscosity and roughness. SysCAD will then calculate the friction factor using the Churchill equation.  
User Pipe K The following field is visible if this method is chosen.  
UserPipeK  Input  The required K value for the Pipe. 
The following 2 fields are visible for the other methods.  
Length / L  Input  The required Pipe Length. 
FittingsLength / FitL  Input  The equivalent pipe fittings Length. Please do not include a value here for fittings if they are already included under MinorK. 
Length and Friction F The following field is visible for this method.  
UserFricFactor / UserFricF  Input  The required friction factor. 
Length, Churchill and Colebrook Friction Factor The following fields are visible for both of these methods.  
Viscosity  Input  The viscosity of the material flowing through the pipe. 
Roughness  Input  The roughness of the pipe. 
Valve  
Valve Settings  
Pump  
Pump Settings 
Adding this Model to a Project
Insert into Configuration file
Sort either by DLL or Group.

DLL: 
Piping2.dll 
→ 
Units/Links 
→ 
Piping: Piping System 
or 
Group: 
Mass Transfer 
→ 
Units/Links 
→ 
Piping: Piping System 
See Project Configuration for more information on adding models to the configuration file.
Insert into Project

Insert Unit 
→ 
Piping 
→ 
Piping System 
See Insert Unit for general information on inserting units.
Example  Entering Elevation Information
 Feed_Tank  Assume at 0 m elevation
 Feed_Pump  Piping System : Seg06 (Pipe4  Pipe to Head tank) has delta height (dH) of 15 m
 Head_tank  Assume at 15 m elevation (tank height 2m)  NOTE that we can't enter an elevation for the tank here, so we need to provide the information in the next unit where the change of height occurs.
 FCV_001  Piping System : Flow control valve to Area1 (See first picture above)
 Head  16.7m (this reflects the elevation head from head_tank, assuming tank is 85% full )  this will calculate the pressure at the start of the FCV_001 piping system.
 Destination elevation is 5m higher