modelPipeCondensing
Extends from PipeCondensingBase (Condensation of pure vapors inside pipes. TwallC, TsurfC and Hc are those of condensation step).
Information
There is no determination of the total condensation length, so it is necessary to be sure that flow doesn't condense before the end of the pipe. There are two possible configurations, selectables using a parameter.One is total condensation. In this case the vapor quality output is made equal to 0, and the maximum condensable flow is calculated. You must supply the pressure at both ends of the pipe. This model reflects the situation of heating tubes provided with steam traps.
The second option is partial condensation. In this case you can specify both ends pressures, or one pressue and the flow. A check is done in order to assure that total condensation doesn't occurs.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Physical data | |||
| Boolean | useTubeLength (from PipePhysical) | true | use the supplied length |
| Modelica.Units.SI.Distance | lTube (from PipePhysical) | 0 | supplied individual tube length |
| Boolean | fixNumTubes (from PipePhysical) | true | if true fixes the number of tubes to numTubes |
| Integer | numTubes (from PipePhysical) | 1 | number of parallel identical paths |
| Boolean | isCircular (from PipePhysical) | true | the pipe is circular in shape |
| Boolean | useDiameter (from PipePhysical) | true | the supplied diameter will be used for calculation of section and perimeter |
| Modelica.Units.SI.Distance | di (from PipePhysical) | 0.0 | supplied internal diameter if path is circular |
| Boolean | useSectionAndPerimeter (from PipePhysical) | false | the supplied section and perimeter will be used |
| Modelica.Units.SI.Area | section (from PipePhysical) | 0 | supplied pipe section if not circular |
| Modelica.Units.SI.Distance | perimeter (from PipePhysical) | 0 | supplied perimeter if not circular |
| Modelica.Units.SI.Distance | thickness (from PipePhysical) | 1e-3 | pipe thickness. Vessel wall thickness for halfcoils |
| Modelica.Units.SI.Distance | roughness (from PipePhysical) | 1.5e-005 | pipe roughness. SS:1.5e-5, Steel new:4.6e-5, Steel old:2.0e-4, Concrete:1.5e-3 |
| Modelica.Units.SI.Distance | thicknessInsul (from PipePhysical) | 0 | insulation thickness |
| Modelica.Units.SI.Density | rhoWall (from PipePhysical) | 8000 | |
| Ports links | |||
| Boolean | useElevDifference (from TwoFluidPorts) | true | introduces, or not, an equation for the ports elevation. Use only in one connector |
| FreeFluids.Types.ElevationOption | elevCalcMethod (from TwoFluidPorts) | FreeFluids.Types.ElevationOption.differential | if useElevDifference==true, selects the equation to use: differential, or absolute for PortB |
| Modelica.Units.SI.Length | elevDifference (from TwoFluidPorts) | 0.0 | used only if previously selected. Positive if PortB higher than PortA |
| Modelica.Units.SI.Length | portBelevation (from TwoFluidPorts) | 0.0 | used only if previously selected. |
| Boolean | calcEnthalpyDifference (from TwoFluidPorts) | true | if true, will calculate the enthalpy difference between ports. Use only in one connector |
| Boolean | passComposition (from TwoFluidPorts) | true | if true, the equation PortA.X=PortB.X will be activated |
| Flow | |||
| Integer | numActiveTubes (from Pipe) | numTubes | number of parallel identical paths used with flow. Default=numTubes |
| Real | pipeComplexity (from Pipe) | 0 | Approx. estimation of equivalent length,0=not used,0.25=supply lines,0.5=long runs, 1=normal,2=valves,4=complex valves |
| Real | equivL_Di (from Pipe) | 0 | Equivalent length of accesories as multiples of Di |
| Real | numVelocityHeads (from Pipe) | 0 | number of velocity heads for pressure loss |
| Modelica.Units.SI.Area | kv (from Pipe) | 0 | This allows for special head loses to be incorporated inside the pipe calculation via Kv |
| Fraction | aperture (from Pipe) | 1 | Fraction of Kv used |
| Boolean | fullBore (from Pipe) | true | true if the full pipe section is used for flow |
| Boolean | isCompressibleFlow (from Pipe) | false | indicates if kinetic energy and momentum are taken into account or not |
| Boolean | twoPhaseFlow (from PipeFlowBase) | false | indicates if there is a two phase flow |
| Heat transfer | |||
| FreeFluids.Types.ThermalType | thermalType (from PipeFlowBase) | FreeFluids.Types.ThermalType.detailed | Alternatives: detailed, isenthalpic, adiabatic, isothermal, fixed W, fixed deltaT. If detailed, W calculation must be supplied |
| Modelica.Units.SI.HeatFlowRate | fixedW (from PipeFlowBase) | 0 | Heat exchange if thermaltype = fixedPower. Positive if heat enters the tube |
| Modelica.Units.SI.TemperatureDifference | fixedDeltaT (from PipeFlowBase) | 0 | fixed T diff. between ports if thermalType = fixedDeltaT. Positive if Tb > Ta |
| Modelica.Units.SI.ThermalConductivity | kWall (from PipeCondensingBase) | 16 | Wall thermal conductivity. typical value for SS=16.7 |
| Modelica.Units.SI.ThermalConductivity | kInsul (from PipeCondensingBase) | 0.04 | Insulation thermal conductivity. Typical value for glass fiber=0.04 W/(K·m) |
| Modelica.Units.SI.ThermalInsulance | foulingF (from PipeCondensingBase) | 0.0002 | Tube side fouling factor.Typical: 0.00018 for thermal oil, or treated cooling water |
| Boolean | useWallsResistance (from PipeCondensingBase) | false | if true, will calculate Twall-Tsurf according to wall conduction, otherwise Twall=Tsurf |
| Real | emissionCoef (from PipeCondensingBase) | 0.26 | emission coefficient of surface typical values: Aluminium:0.1, SS:0.15, dirty metal: 0.45, non-metallic:0.94 |
| Boolean | fullHTperimeter (from PipeCondensingBase) | true | indicates if all active perimeter is used in heat transfer. It is false for halfpipes |
| CondensationOption | condensationOption | FreeFluids.Types.CondensationOption.totalCondensation | |
| Boolean | useThermalConnector | true | if true, the thermal connector will be used for heat transfer. Otherwise a specific calculation must be coded |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| FreeFluids.Interfaces.FluidPortA | PortA (from TwoFluidPorts) | ||
| FreeFluids.Interfaces.FluidPortB | PortB (from TwoFluidPorts) | ||
| FreeFluids.Interfaces.HeatPortB | PortH |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Units.SI.Diameter | Di (from PipePhysical) | pipe internal diameter only if circular, otherwise four times Section/Perimeter | |
| Modelica.Units.SI.Area | PathSection (from PipePhysical) | Internal section of the tube. But not the flow section if double pipe | |
| Modelica.Units.SI.Distance | PathPerimeter (from PipePhysical) | Internal perimeter of the tube. But not the flow perimeter if double pipe | |
| Modelica.Units.SI.Distance | Ltotal (from PipePhysical) | total pipe length, as necessary for obtainning its total weight | |
| Modelica.Units.SI.Distance | Ltube (from PipePhysical) | pipe path length, as necessary for obtainning friction loss | |
| Integer | NumTubes (from PipePhysical) | number of parallel identical paths | |
| Modelica.Units.SI.Area | SiTube (from PipePhysical) | each tube internal surface | |
| Modelica.Units.SI.Area | SiTotal (from PipePhysical) | total pipe internal surface | |
| Modelica.Units.SI.Volume | ViTube (from PipePhysical) | each tube internal volume | |
| Modelica.Units.SI.Volume | ViTotal (from PipePhysical) | total pipe internal volume | |
| Modelica.Units.SI.Diameter | Do (from PipePhysical) | pipe external diameter | |
| Modelica.Units.SI.Diameter | Dinsul (from PipePhysical) | pipe diameter with insulation | |
| Modelica.Units.SI.Area | SoTube (from PipePhysical) | each tube external surface | |
| Modelica.Units.SI.Area | SoTotal (from PipePhysical) | total pipe external surface | |
| Modelica.Units.SI.Volume | VoTube (from PipePhysical) | each tube external volume | |
| Modelica.Units.SI.Volume | VoTotal (from PipePhysical) | total pipe external volume | |
| Modelica.Units.SI.Area | SinsulTube (from PipePhysical) | each tube insulation surface | |
| Modelica.Units.SI.Area | SinsulTotal (from PipePhysical) | total pipe insulation surface | |
| Modelica.Units.SI.Mass | MassPipeTotal (from PipePhysical) | total mass of the pipe | |
| Modelica.Units.SI.SpecificEnthalpy | Hdiff (from TwoFluidPorts) | specific enthalpy difference: Port B - Port A | |
| Modelica.Units.SI.PressureDifference | Pdiff (from TwoFluidPorts) | pressure difference: Port B - Port A | |
| Integer | NumActiveTubes (from Pipe) | number of parallel identical paths used with flow. | |
| Real | Slope (from Pipe) | pipe slope as (PortB.Elevation-PortA.Elevation)/Ltube | |
| Modelica.Units.SI.Area | SiActive (from Pipe) | active pipe internal surface | |
| Modelica.Units.SI.Volume | ViActive (from Pipe) | active pipe internal volume | |
| Modelica.Units.SI.Area | SoActive (from Pipe) | active pipe external surface | |
| Modelica.Units.SI.Volume | VoActive (from Pipe) | active pipe external volume | |
| Modelica.Units.SI.Area | SinsulActive (from Pipe) | active pipe external surface | |
| Modelica.Units.SI.Distance | LeTube (from Pipe) | equivalent length of the pipe for pressure loss | |
| Modelica.Units.SI.Area | PathSectionActive (from Pipe) | section of each tube used for flow calculation | |
| Modelica.Units.SI.Distance | PathPerimeterActive (from Pipe) | perimeter of each tube used for flow calculation | |
| Modelica.Units.SI.Diameter | Dh (from Pipe) | four time the hydraulic radius | |
| Modelica.Units.SI.Mass | MassProductTotal (from Pipe) | Mass of product inside all the tubes | |
| Modelica.Units.SI.Pressure | PLossFriction (from Pipe) | friction head loss | |
| Modelica.Units.SI.Velocity | Va (from PipeFlowBase) | ||
| Modelica.Units.SI.Velocity | Vb (from PipeFlowBase) | ||
| Medium.Density | RhoA (from PipeFlowBase) | density at Port A | |
| Medium.Density | RhoB (from PipeFlowBase) | density at PortB | |
| Medium.ThermodynamicState | StateA (from PipeFlowBase) | state at PortA | |
| Medium.ThermodynamicState | StateB (from PipeFlowBase) | state at PortB | |
| Modelica.Units.SI.VolumeFlowRate | Qa (from PipeFlowBase) | volume flow rate at PortA | |
| Modelica.Units.SI.VolumeFlowRate | Qb (from PipeFlowBase) | volume flow rate at PortB | |
| Medium.Temperature | Ta (from PipeFlowBase) | ||
| Medium.Temperature | Tb (from PipeFlowBase) | ||
| Modelica.Units.SI.Power | W (from PipeFlowBase) | heat transfer between fluid and wall. Positive if fluid inputs heat | |
| Medium.Temperature | TwallC (from PipeCondensingBase) | average wall temperature (tube inside) along condensation | |
| Medium.Temperature | TsurfC (from PipeCondensingBase) | average superficial temperature (tube outside) along condensation | |
| Modelica.Units.SI.Area | SactiveHT (from PipeCondensingBase) | internal surface potentially active for heat transfer, due to partial perimeter usage | |
| Modelica.Units.SI.CoefficientOfHeatTransfer | Hc (from PipeCondensingBase) | average heat transfer coefficient along condensation | |
| Medium.ThermodynamicState | StateFilm (from PipeCondensingBase) | average state for condensation film physical properties calculation | |
| Modelica.Units.SI.Density | RhoFilm (from PipeCondensingBase) | liquid density at film temperature | |
| Medium.Density | RhoG (from PipeCondensingBase) | saturated gas density | |
| Medium.DynamicViscosity | MuG (from PipeCondensingBase) | dynamic viscosity of saturated gas | |
| Modelica.Units.SI.SpecificEnergy | Hvc (from PipeCondensingBase) | gas cooling plus condensation heat(J/kg). Inlet can be sligthly superheated | |
| Medium.MassFraction | Xin (from PipeCondensingBase) | vapor quality at inlet as fraction in mass | |
| Medium.MassFraction | Xout (from PipeCondensingBase) | vapor quality at outlet as fraction in mass | |
| Medium.Temperature | Tfilm (from PipeCondensingBase) | liquid film average absolute temperature | |
| Modelica.Units.SI.SpecificHeatCapacity | CpFilm (from PipeCondensingBase) | liquid specific heat capacity at film temperature | |
| Modelica.Units.SI.ThermalConductivity | Kfilm (from PipeCondensingBase) | liquid thermal conductivity at film temperature | |
| Modelica.Units.SI.PrandtlNumber | PrFilm (from PipeCondensingBase) | liquid Prandt number at film temperature | |
| Medium.DynamicViscosity | MuFilm (from PipeCondensingBase) | liquid viscosity at film temperature | |
| Medium.DynamicViscosity | MuWallC (from PipeCondensingBase) | average wall viscosity along condensation | |
| Modelica.Units.SI.ReynoldsNumber | ReLc (from PipeCondensingBase) | Reynolds number of the liquid phase at the end of condensation | |
| Modelica.Units.SI.ReynoldsNumber | ReVDIc (from PipeCondensingBase) | At end of condensation. Uses mass flow per unit perimeter length =condensate outlet Reynolds/4 | |
| Real | Xm (from PipeCondensingBase) | mean vapor quality | |
| Real | NuL (from PipeCondensingBase) | ||
| Real | NuT (from PipeCondensingBase) | ||
| Real | NuCg (from PipeCondensingBase) | Nusselt(special) number laminar, turbulent, combined, for gravity governed | |
| Modelica.Units.SI.CoefficientOfHeatTransfer | Hcg (from PipeCondensingBase) | gravity governed heat transfer coefficient | |
| Modelica.Units.SI.CoefficientOfHeatTransfer | Hcs (from PipeCondensingBase) | gas shear governed heat transfer coefficient | |
| Modelica.Units.SI.CoefficientOfHeatTransfer | Uc (from PipeCondensingBase) | overall heat transfer coefficient | |
| Modelica.Units.SI.Power | Wc (from PipeCondensingBase) | heat transfer between fluid and wall along condensation. Positive if fluid inputs heat | |
| Medium.ThermodynamicState | StateGas (from PipeCondensingBase) | saturated gas state | |
| Medium.ThermodynamicState | StateWallC (from PipeCondensingBase) | Thermodynamic state at wall along condensation | |
| Modelica.Units.SI.Area | SiCond (from PipeCondensingBase) | internal surface used in condensation | |
| Modelica.Units.SI.ReynoldsNumber | ReGc (from PipeCondensingBase) | Reynolds number at condensation if all was gas | |
| Real | FlC (from PipeCondensingBase) | Darcy's friction factor if all liquid | |
| Real | FgC (from PipeCondensingBase) | Darcy's friction factor if all gas | |
| Modelica.Units.SI.Pressure | PLossFrictL (from PipeCondensingBase) | friction head loss if all was liquid | |
| Modelica.Units.SI.Pressure | PLossFrictG (from PipeCondensingBase) | friction head loss if all was gas | |
| Modelica.Units.SI.Pressure | PLossFrictC (from PipeCondensingBase) | friction head loss at condensation | |
| Medium.Temperature | Tsurf | TsurfC | average superficial temperature (tube outside) along condensation |
| Modelica.Units.SI.CoefficientOfHeatTransfer | H | Hc | average heat transfer coefficient along condensation |