View source for Pipe

[[Category:Models]]
{{Navigation|[[Models]]|[[Models#General Models|General Models]]}}

{| border="1" cellpadding="5" cellspacing="0"
!Width=250 font style="background: #ebebeb" |[[Pipe]]
!Width=250 |[[Pipe - Dynamic Mode]]
|}
----
{{TOC}}
== General Description ==

A '''Pipe''' (or '''Link''') is used to transfer material between two units. Each Pipe can have only one source and one destination. A large amount of information is contained in a pipe for reporting and control.

* In Steady State (ProBal) mode, the Pipe serves as a simple link, requiring very little configuration.
* In Dynamic mode the pipe contains additional fields relating to required flows and network configuration. Please see [[Pipe - Dynamic Mode]] for more information. 

=== Enabling Sub-Models ===

When a Pipe, or Link, is inserted, it will by default be a 'Simple' pipe, i.e. Flow conditions into the Pipe = Flow conditions out of the Pipe.  However, users may specify a pressure drop and/or enable sub-models in a pipe. The user can select the sequence in which the sub-models act, however the pressure drop is applied first. To enable sub-models the user must un-tick the 'Simplify' tickbox, as shown below:

[[Image:Pipe nonsimple.png]]

'''Available Sub-Models'''

Evaluation Block:

# [[Makeup Block (MU)|Makeup Blocks]] (one or more) may be enabled in a Pipe.  This allows the user to control the addition of streams such as reagents, water, air, etc. to the pipe, often without having to use a PID or General controller.
# The [[Reaction Block (RB)]] allows the user to configure any number of reactions within the pipe.
# The [[Environmental Heat Exchanger (EHX)|Environmental Heat Exchanger Block]] allows the user to add or remove energy from the pipe using a number of different methods.
# The [[Evaporation Block (Evap)|Evaporation Block]] allows the user to set the evaporation of either water only or a mixture of water and all other species that are specified as both liquid and vapour.
# The [[Vapour Liquid Equilibrium (VLE)|Vapour Liquid Equilibrium Block]] will attempt to ensure that the vapours and liquids of the selected species will be in equilibrium in the pipe.  For example, if the equilibrium species is water and the pipe is at atmospheric pressure, then SysCAD will maintain the temperature at, or below, the saturated temperature of 99.97°C by evaporating water if required.
# [[Discard Block (DB)|Discard Blocks]] (one or more) may be enabled in a Pipe. This allows the user to control the discarding of material from the Pipe, usually without having to use a PID or General controller. This is available in Build 138 or later.

=== Model Procedures ===

[[Model Procedures]] allows the user to implement code directly within the Pipe.  The code used is almost identical to the code in pgm files.

To enable this, on the "Info" tab page tick the "Procedures" tickbox, as shown below:

[[Image:Pipe-MP_Setup.png]]

== Flowchart ==

The following shows the sequence of events if the Pipe is not simplified and any sub model options are enabled.

[[Image:Pipe - ProBal.jpg]]

== Model Theory ==

=== Pressure Drop Equations ===

<u>'' Darcy Pressure Drop for slurry''</u>

:<math>
  \Delta P = \left( \rho \times g \times dZ \right)  + \left[ \cfrac {1}{2} \times \rho \times v^2 \times \left( \cfrac{f L}{D} + K_{m} \right) \right]
</math>
where
* <math>v</math> is the fluid velocity
* <math>dZ</math> is the elevation change (positive for increasing elevation)
* <math>K_m</math> is a term for minor losses typically due to fittings such as valves and other restrictions. Note that in some situations, much of the pressure drop is from such "minor losses".

*The ''Friction Factor'' <math>f</math>  can be specified or calculated <sup>[1]</sup> as: 

<math>
f/8 = \left[\left(\frac{8}{\mathrm{Re}}\right)^{12} + \frac{1}{(\Theta_1 + \Theta_2)^{1.5}}\right]^{\frac{1}{12}}
</math>
:where
:<math>\Theta_1 = \left[-2.457 \ln\left( \left(\frac{7}{\mathrm{Re}}\right)^{0.9} + 0.27\frac{\varepsilon}{D}\right)\right]^{16}</math>
:<math>\Theta_2 = \left(\frac{37530}{\mathrm{Re}}\right)^{16}</math>


*Reynolds number 
:<math>\mathrm{Re} = \cfrac{\rho v D }{\mu}</math> 
::Re has a lower limit of 1e-9.
::Viscosity has a lower limit of 1e-12.
*<math>\rho</math>  is density of the complete mixture (all phases)
*<math>D = D_i - (2 \times S)</math> where <math>D_i</math> is the inside pipe diameter and <math>S</math> is scale thickness. 
*<math>L</math> is the total length including fittings. 

[1] Churchill, S.W. (November 7, 1977). ''"Friction-factor equation spans all fluid-flow regimes"'' Chemical Engineering: 91–92.

== Data Sections ==

The [[Pipe - Dynamic Mode|Dynamic Pipe]] contains additional fields relating to required flows and network configuration.  Only the fields shown for ProBal are described here.

=== Summary of Data Sections ===

The pipe access window may consist of a number of sections. This number may increase or decrease, based on user configuration and / or number of species.

# '''[[#Pipe Page|Pipe-1]]''' - The first section, contains general information relating to material flowing through the pipe, the Source and Destination units and allows the user to enable [[Demand]].  To enable the sub models (for example [[Reaction Block (RB)|Reactions]] or [[EHX|Environmental Heat Exchange]]) in a Pipe, the user must first disable ''Simplify'' and then the [[Evaluation Blocks|Evaluation Block (EB)]] will be visible.
# '''[[Phase Change (PC)|PC]]''' - Optional tab that is visible if EB.Solubility.On and/or EB.PhaseChange@T.On is enabled on the first tab.
# '''[[RB]]''' - Optional tab that is visible if Reactions are enabled.
# '''[[EHX]]''' - Optional tab that is visible if Environmental Heat Exchanger is enabled.
# '''[[Evap]]''' - Optional tab that is visible if Evaporator is enabled.
# '''[[VLE]]''' - Optional tab that is visible if Vapour Liquid Equilibrium is enabled.
# '''[[MU]]''' - Optional tab, or multiple tabs if more than 1 Makeup Block is selected, Only visible if one of more Makeup Blocks are enabled in the Evaluation Block.
# '''[[DB]]''' - Optional tab, or multiple tabs if more than 1 Discard Block is selected.  Only visible if one of more Discard Blocks are enabled in the Evaluation Block. Only available in Build 138 or later.
# '''[[#Qi and Qo Tab Pages|Qi]]''' - This and subsequent tab pages, e.g. Qi.. and Sp, shows the properties of the inlet stream.  This tab is only visible if ''Simplify'' is NOT enabled.
#* This is before any [[Evaluation Blocks|Evaluation Block]] sub-models are evaluated (see the Flowchart above).
# '''[[#Qi and Qo Tab Pages|Qo]]''' - This and subsequent tab pages, e.g. Qo.. and Sp, shows the properties of the outlet stream.  This tab is always visible.
#* This is before any [[Evaluation Blocks|Evaluation Block]] sub-models are evaluated (see the Flowchart above).
# '''[[Common Data Sections#Common Data on Info Tab Page|Info]]''' tab - contains general settings for the unit and allows the user to include documentation about the unit and create Hyperlinks to external documents.
# '''[[Model Procedures#MP Page|MP]]''' tab - Optional tab, only visible if ''Procedures'' have been enabled on the '''[[Common Data Sections#Common Data on Info Tab Page|Info]]''' tab page.
# '''[[Links Table|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.

===Pipe Page===
'''Unit Type: Pipe-1''' - The first tab page in the access window will have this name.
{|   border="1" cellpadding="5" cellspacing="0" 
|Width=150|'''Tag (Long/Short)'''||Width=140|'''Input / Calc'''||'''Description/Calculated Variables / Options'''
|-
{{Common Data on First Tab Page|ModelType=Pipe}}
|-
|  colspan="3" font style="background: #ebebeb"    |

====Results: Inlet Flow Conditions====
|-
| MassFlow / Qm || font style="background: #ebebeb" | Calc || The total mass of material flowing through the pipe.
|-
| VolFlow / Qv || font style="background: #ebebeb" | Calc || The total volumetric flow through the pipe.
|-
| VolFlow / NQv || font style="background: #ebebeb" | Calc || The normalised volumetric flow through the pipe. The volume is calculated at '''N'''ormal '''T'''emperature and '''P'''ressure (NTP), default values are 25°C and 101.325kPa.   This is only relevant for flows containing vapours.<br> NTP can be specified by the user in the configuration file (see [[General Configuration|Project Configuration]]).
|-
| TemperatureIn / Ti || font style="background: #ebebeb" | Calc || The temperature of the material flowing into the pipe.
|-
| Temperature / T || font style="background: #ebebeb" | Calc || The temperature of the material flowing into the pipe.
|-
| Density / Rho || font style="background: #ebebeb" | Calc || The density of the material flowing into the pipe.
|-
| NDensity / NRho || font style="background: #ebebeb" | Calc || The normalised density of the material flowing through the pipe (using inlet conditions). The normalised density is calculated at '''N'''ormal '''T'''emperature and '''P'''ressure (NTP), default values are 25°C and 101.325kPa. This is only relevant for flows containing vapours. <br>NTP can be specified by the user in the configuration file (see [[General Configuration|Project Configuration]]).
|-
| PressureIn / Pi || font style="background: #ebebeb" | Calc || The pressure into the pipe. 
|-
|   colspan="3" font style="background: #ebebeb"  |
====Outlet Flow Conditions====
|-
| TemperatureOut / To || font style="background: #ebebeb" | Calc || The temperature of the material flowing out of the pipe.
|-
| PressureOut / Po ||font style="background: #ebebeb" | Calc || The pressure out of the pipe.
|-
|   colspan="3" font style="background: #ebebeb"   |
==== Connections ====
|-
| SourceLink / SrcIO ||  font style="background: #ebebeb"  | Display || The tag of the pipe's source unit, including the I/O connection point (PortID) of that unit. <br> E.g. If the source is a Thickener, this will show whether the pipe is connected to the Overflow or the Underflow.
|-
| DestinationLink / DstIO || font style="background: #ebebeb" | Display || The tag of pipe's destination unit, including the I/O connection point (PortID) of that unit.
|-
| SourcePortID / SrcPortID || font style="background: #ebebeb"  | Display || The I/O connection point of the source unit.
|-
| DestinationPortID / DstPortID || font style="background: #ebebeb" | Display || The I/O connection point of the destination unit.
|-
| SourceFlange / SrcFlange || font style="background: #ebebeb" | Display || The tag of pipe's source [[Flange]]. <br> If the pipe is a tear stream (i.e. if the associated source Flange has a [[Tear]]), this will be noted by the tag comment "Has a Tear".
|-
| DestinationFlange / DstFlange || font style="background: #ebebeb" | Display || The tag of pipe's destination [[Flange]].
|-
| ConnectDescription / ConnectDesc || font style="background: #ebebeb" | Display || A description of the pipe based on the source and destination units, useful for reporting. This includes the Port ID if unit has more than one type available. <br> SysCAD will copy this field into the ''[[Common Data Sections#Common Data on First Tab Page|GenDesc]]'' field IF the ''EqpDesc'' field on the ''[[Common Data Sections#Common Data on First Tab Page|Info]]'' tab is blank. 
|-
|  colspan="3" font style="background: #ebebeb"  |

==== Requirements ====
|-
| Configuration.Exists || font style="background: #ebebeb" | Display || This field indicates if the pipe can be simplified. 0 = no configuration (can be simplified), 1 = configured (cannot be simplified). Types of configuration include reactions, makeups, qualities or species model configuration.
|-
| Simplify || Tick Box || By default this state is enabled, causing the pipe to be a 'simple' pipe with only the ''Qo'' tabs being visible.  The ''Qi'' tags are unavailable for reporting, etc.  If the user wishes to set anything in the pipe or enable reactions, heat loss, etc., then this tick box must be disabled.  Additional fields will then become visible and the user may set sub-models in the pipe.
|-
| Simplify.Blocked || font style="background: #ebebeb" | Display || This field indicates if a pipe has been blocked from being simplified due to some configuration in the pipe. 1 = Simplify has been ticked but pipe is not simplified due to some configuration (Configuration.Exists = 1). 0 = Simplify is not ticked or pipe has been simplified.
|-
| Show.Qi || Tick Box || This tickbox is only visible if the pipe is NOT Simplified.  The user may enable this to view both the Qi (flow into the pipe) and Qo (flow out of the pipe) tabs, which may be useful if the user has added reactions, heat exchange, etc. to the pipe. When the pipe is not simplified and Show.Qi is off the Qi tags are still accessible for reporting, trends, etc.
|-
|font style="background: #ebebeb" colspan="3" |

==== EB (Flow Evaluation Block) ====
'''Note''' This section is only visible if ''Simplify'' is Disabled.
{{EB Evaluation Data Section | Makeups = Yes | Reactions = Yes | HeatXChg = No | EnvironHX = Yes | Evaporation = Yes | VLE = Yes | Discard = Yes}}
|-
|font style="background: #ebebeb" colspan="3" |

==== General Demand ====
|-
|  valign="top"  | Qm_Avail.Source / Src || font style="background: #ebebeb" | Display || The mass flow available at the source, such as a Feeder or a Flash Tank.  This field is only useful when Demand mode is used, either in a Feeder or as part of the [[Flash Train]] macro model.<br>
'''Note''' This field will only be visible if ''ShowDemandAvail'' is enabled in [[Plant_Model_-_FlwSolve#Demand_Configuration|Plant Model - FlwSolve - Demand Configuration]].
|-
|  valign="top"  | Qm_Avail.Dest / Dst || font style="background: #ebebeb" | Display || The mass flow available for the destination.<br>
'''Note''' This field will only be visible if ''ShowDemandAvail'' is enabled in [[Plant_Model_-_FlwSolve#Demand_Configuration|Plant Model - FlwSolve - Demand Configuration]].
|-
|  valign="top"  | Qm_Demand.Source / Src || font style="background: #ebebeb" | Display || The flow required at the source, i.e. upstream.
|-
| Qm_Demand.Block / Blk || Tickbox || If this is enabled, then the Demand will be ''Blocked'' from perpetrating either up or downstream.  This is used to prevent demand in a recycle and also to prevent a single unit seeing two feeders with Demand enabled.  (Please see [[Demand]] for further information)
|-
| Qm_Demand.BlockLowQm / BlkLowQm || Tickbox || Available in Build 139 and later.  If this is enabled, then the Demand will be ''Blocked'' from perpetrating if the demand from the downstream destination or user specified Qm_Demand.Reqd is small (i.e. less than PlantModel.DemandThresholdQm).  This is used to prevent demand flow lower than the [[Plant_Model_-_FlwSolve#Demand_Configuration|Demand Threshold]].
|-
|  valign="top"  | Qm_Demand.Reqd ||  valign="top"   | Input || The user may set a required mass flow through the pipe. This flow will filter back to the source unit and the model will attempt to satisfy this flow requirement.<br> '''Note''': If the pipe is connected to a Feeder, the user should enable the variable 'Demand.On' on the Feeder. The Feeder will then deliver the mass flow required by the pipe. See [[Demand]] for more information on this feature.
|-
|  valign="top"  | Qm_Demand.Dest / Dst || font style="background: #ebebeb" | Display || Flow required at destination, i.e. downstream.  In Build 139 and later, if the demand is actively being blocked, some description will be shown to the right of the field to provide user feedback.  Options are: "Blocked by Tear!", "Blocked!" and "Blocked by LowQm Threshold!".
|-
| colspan="3" font style="background: #ebebeb" |

==== FlashTrain Demand ====
|-
|  valign="top"  | Ft.Qm_Avail.Source || font style="background: #ebebeb" | Display || The mass flow available at the source.<br>
'''Note''' This field will only be visible if ''ShowDemandAvail'' is enabled in [[Plant_Model_-_FlwSolve#Demand_Configuration|Plant Model - FlwSolve - Demand Configuration]].
|-
|  valign="top"  | Ft.Qm_Avail.Dest || font style="background: #ebebeb" | Display || The mass flow available for the destination.<br>
'''Note''' This field will only be visible if ''ShowDemandAvail'' is enabled in [[Plant_Model_-_FlwSolve#Demand_Configuration|Plant Model - FlwSolve - Demand Configuration]].
|-
|  valign="top"  | Ft.Qm_Demand.Source || font style="background: #ebebeb" | Display || The vapour flow required at the source, e.g. flash tank flash vapour.
|-
|  valign="top"  | Ft.Qm_Demand.Dest || font style="background: #ebebeb" | Display || Flow required at destination, e.g. flash vapour to the heat exchanger.
|-
| colspan="3" font style="background: #ebebeb" |

==== Pressure Drop ====
'''Note''' This section is only visible if ''Simplify'' is Disabled.
|-
| rowspan="6" valign="top"  | PressMethod || None || There is no pressure change in the pipe.
|-
| Drop || The user can enter a fixed pressure drop in the pipe. The default is 0.
|-
| Boost || The user can enter a fixed pressure boost in the pipe. The default is 0.
|-
| Darcy || The pressure change will be calculated using the Darcy equation.
|-
| Fixed || The user can type in a fixed pressure value.
|-
| Diameter Velocity || The user may specify a velocity and SysCAD will calculate a pipe diameter to give the required velocity.<br>'''Note:''' SysCAD does NOT calculate a pressure drop for this method.
|-
| PressDropReqd || Input || Allows the user to enter a pressure drop.  Visible when PressMethod = "Drop".
|-
| PressBoostReqd || Input || Allows the user to enter a pressure boost.  Visible when PressMethod = "Boost".
|-
| PressureReqd|| Input || Allows the user to specify the outlet pressure of the pipe. Visible when PressMethod = "Fixed".
|-
| PressChange / dP ||  font style="background: #ebebeb" | Calc || The calculated pressure change across the pipe, based on the method selected by the user.  This value will be zero for the 'None' and 'Diameter_Velocity' methods.
|-
| PressDrop / Pdrop ||  font style="background: #ebebeb" | Calc || The calculated pressure drop across the pipe, based on the method selected by the user.  This value will be zero for the 'None' and 'Diameter_Velocity' methods.<br>This value will always have the opposite sign to ''dP'' above.
|-
|  colspan="3" font style="background: #ebebeb"| The following fields are only visible if the '''Diameter_Velocity''' method is selected.
|-
| Diam ||  font style="background: #ebebeb" | Display || The estimated nominal diameter of the pipe based on the user defined Velocity. 
|-
| Velocity / Vel ||  Input || The user defined target velocity, SysCAD will estimate the required Pipe diameter needed to achieve this required velocity. 
|-
|  colspan="3" font style="background: #ebebeb"| The following fields are only visible if the '''Darcy''' method is selected.  see [[#Model Theory|Model Theory]]
|-
| Diameter / Diam || Input || The Inner diameter of the pipe.
|-
| ScaleBuildUp || Input || The build up of material inside the pipe, thus reducing the ID of pipe. For a clean pipe, this value = 0.
|-
| rowspan="2" valign="top" | K_Method || Calc K || Calculate K from user defined values.
|-
| Define_K || Calculates the pressure drop using user specified pressure drop factor.
|-
| K_Value || Input / Calc || The pressure drop factor: K = f * L/D.  If the '''Define_K''' method is selected, this is an input, otherwise it is calculated.
|-
| colspan="3" | The following fields are visible if '''Calc_K''' method is selected.
|-
| Length || Input || The actual length of the pipe.  
|-
| FittingsLength || Input || The fittings length of the pipe.
|-
| rowspan="2" valign="top" | f_Method || Calc_f || Calculate the friction factor from user defined values.
|-
| Define_f || The user can define a friction factor (f) to be used
|-
| FricFac || Input || The Darcy friction factor (f). Please note this is equivalent to (4) times Fanning's friction factor.  Visible if '''Define_f''' method is selected.
|-
| Viscosity || Input || The Viscosity of the material flowing through the pipe. Visible if '''Calc_f''' method is selected.
|-
| PipeRough || Input || The Pipe Roughness value.  Visible if '''Calc_f''' method is selected.
|-
| ReynoldsNo / Re || font style="background: #ebebeb" | Calc || The calculated Reynolds number. Visible if '''Calc_f''' method is selected.
|-
| FricFac || font style="background: #ebebeb" | Calc || The calculated Darcy friction factor (f). Visible if '''Calc_f''' method is selected. Please note this is equivalent to (4) times Fanning's friction factor.
|-
| K_MinorLosses || Input || K value for minor pressure losses in the pipe.
|-
| PipeDeltaZ || Input || The overall change of height for the pipe.
|-
| Velocity / Vel ||  font style="background: #ebebeb" | Calc || The velocity in the pipe.<br> '''Note''': a warning will be given if the velocity in the pipe is too high. Velocity limits maybe set/adjusted via '''View'''-'''PlantModel'''-'''RC''' Tab.  See [[Plant_Model_-_RC#Range_Checks|Range Checks]]
|-
|   colspan="3" font style="background: #ebebeb"   |

==== Tear ====
|-
|  rowspan="3" valign="top"  | Priority ||First || Force the stream order to be first in the solver network.
|- 
| Normal || SysCAD determines the priority of the stream in the solver network and whether the stream should include a [[Tear]] and its solving order.
|-
|Last || Force the stream order to be last in the solver network.
|-
| rowspan="2" valign="top" | ReqdType || TearIfReqd || ("NoTear" prior to {{Removed139|33098||y}}.) No manual tear is required. A [[Tear]] may be created if required by the solver.
|- 
| ManualTear || This will force SysCAD to prioritise setting this pipe as a [[Tear]] stream. This option is for when the user wants to influence the location of the tear stream in a recycle. The existing system-selected tear stream in the recycle loop will be reset to have no tear.  It is also possible to create ''more'' tears than are required.  In some flowsheets, with some arrangement of controllers, it can be possible to reduce the number of iterations required to converge to a solution and/or reduce instability while converging.
|- 
| rowspan="3" valign="top" | Type|| font style="background: #ebebeb" | NoTear || The stream has no tear.
|-
| font style="background: #ebebeb" | SystemTear || SysCAD has analysed the network and determined that the stream is a [[Tear]] stream because it is part of a recycle loop and is the most efficient stream to tear.
|-
| font style="background: #ebebeb" | ManualTear || The user has manually set this stream as a [[Tear]] stream.
|-
| Flange || font style="background: #ebebeb" | Display || The tag of the pipe's source [[Flange]] that may have an associated [[Tear]]. If this Flange has a Tear, this will be noted with a tag comment and the TearBlock field will contain the relevant Tear tag.
|-
| TearBlock || font style="background: #ebebeb" | Display || If the Pipe is a tear stream, this field contains the relevant [[Tear]] tag.
|}

===Qi and Qo Tab Pages===

{{ Qo Data Section | UnitOp=Pipe }}

== Hints and Comments ==

# The user must ensure that the ''View'' and ''Phase'' options will display the required variables. e.g. if the concentration of H2SO4(aq) is required, then the ''View'' would be 'CompntConc' and ''Phase'' should be 'Liquid'. If ''Phase ''is 'All', then the model calculates the acid concentration using the volume of solids, liquids and vapours.
# If the pipe is connected to a unit that is 'Reset' or emptied using the 'SetState' command then the output of the pipe, or the 'Qo' section will show zero flow.