Package Modelica.​Fluid.​Examples.​HeatExchanger.​BaseClasses
Additional models for heat exchangers

Information

This icon shall be used for a package/library that contains base models and classes, respectively.

Extends from Modelica.​Icons.​BasesPackage (Icon for packages containing base classes).

Package Contents

NameDescription
BasicHXSimple heat exchanger model
WallConstPropsPipe wall with capacitance, assuming 1D heat conduction and constant material properties

Model Modelica.​Fluid.​Examples.​HeatExchanger.​BaseClasses.​BasicHX
Simple heat exchanger model

Information

Simple model of a heat exchanger consisting of two pipes and one wall in between. For both fluids geometry parameters, such as heat transfer area and cross section as well as heat transfer and pressure drop correlations may be chosen. The flow scheme may be concurrent or counterflow, defined by the respective flow directions of the fluids entering the component. The design flow direction with positive m_flow variables is counterflow.

Parameters

TypeNameDefaultDescription
Lengthlength Length of flow path for both fluids
IntegernNodes2Spatial segmentation
ModelStructuremodelStructure_1Types.​ModelStructure.​av_vbDetermines whether flow or volume models are present at the ports
ModelStructuremodelStructure_2Types.​ModelStructure.​av_vbDetermines whether flow or volume models are present at the ports
AreacrossArea_1 Cross sectional area
AreacrossArea_2 Cross sectional area
Lengthperimeter_1 Flow channel perimeter
Lengthperimeter_2 Flow channel perimeter
final Booleanuse_HeatTransfertrue= true to use the HeatTransfer_1/_2 model
Areaarea_h_1 Heat transfer area
Areaarea_h_2 Heat transfer area
Lengths_wall Wall thickness
ThermalConductivityk_wall Thermal conductivity of wall material
SpecificHeatCapacityc_wall Specific heat capacity of wall material
Densityrho_wall Density of wall material
final Areaarea_h0.5 * (area_h_1 + area_h_2)Heat transfer area
final Massm_wallrho_wall * area_h * s_wallWall mass
BooleanallowFlowReversalsystem.​allowFlowReversalallow flow reversal, false restricts to design direction (port_a -> port_b)
DynamicsenergyDynamicssystem.​energyDynamicsFormulation of energy balance
DynamicsmassDynamicssystem.​massDynamicsFormulation of mass balance
DynamicsmomentumDynamicssystem.​momentumDynamicsFormulation of momentum balance, if pressureLoss options available
TemperatureTwall_start Start value of wall temperature
TemperaturedT Start value for pipe_1.T - pipe_2.T
Booleanuse_T_starttrueUse T_start if true, otherwise h_start
AbsolutePressurep_a_start1Medium_1.​p_defaultStart value of pressure
AbsolutePressurep_b_start1Medium_1.​p_defaultStart value of pressure
TemperatureT_start_1if use_T_start then Medium_1.T_default else Medium_1.temperature_phX(0.5 * (p_a_start1 + p_b_start1), h_start_1, X_start_1)Start value of temperature
SpecificEnthalpyh_start_1if use_T_start then Medium_1.specificEnthalpy_pTX(0.5 * (p_a_start1 + p_b_start1), T_start_1, X_start_1) else Medium_1.h_defaultStart value of specific enthalpy
MassFractionX_start_1[Medium_1.nX]Medium_1.​X_defaultStart value of mass fractions m_i/m
MassFlowRatem_flow_start_1system.​m_flow_startStart value of mass flow rate
AbsolutePressurep_a_start2Medium_2.​p_defaultStart value of pressure
AbsolutePressurep_b_start2Medium_2.​p_defaultStart value of pressure
TemperatureT_start_2if use_T_start then Medium_2.T_default else Medium_2.temperature_phX(0.5 * (p_a_start2 + p_b_start2), h_start_2, X_start_2)Start value of temperature
SpecificEnthalpyh_start_2if use_T_start then Medium_2.specificEnthalpy_pTX(0.5 * (p_a_start2 + p_b_start2), T_start_2, X_start_2) else Medium_2.h_defaultStart value of specific enthalpy
MassFractionX_start_2[Medium_2.nX]Medium_2.​X_defaultStart value of mass fractions m_i/m
MassFlowRatem_flow_start_2system.​m_flow_startStart value of mass flow rate
Lengthroughness_12.5e-5Absolute roughness of pipe (default = smooth steel pipe)
Lengthroughness_22.5e-5Absolute roughness of pipe (default = smooth steel pipe)

Connectors

TypeNameDescription
FluidPort_bport_b1 
FluidPort_aport_a1 
FluidPort_bport_b2 
FluidPort_aport_a2 

Model Modelica.​Fluid.​Examples.​HeatExchanger.​BaseClasses.​WallConstProps
Pipe wall with capacitance, assuming 1D heat conduction and constant material properties

Information

Simple model of circular (or any other closed shape) wall to be used for pipe (or duct) models. Heat conduction is regarded one dimensional, capacitance is lumped at the arithmetic mean temperature. The spatial discretization (parameter n) is meant to correspond to a connected fluid model discretization.

Parameters

TypeNameDefaultDescription
Integern1Segmentation perpendicular to heat conduction
Lengths Wall thickness
Areaarea_h Heat transfer area
Densityrho_wall Density of wall material
SpecificHeatCapacityc_wall Specific heat capacity of wall material
ThermalConductivityk_wall Thermal conductivity of wall material
Massm[n]fill(rho_wall * area_h * s / n, n)Distribution of wall mass
DynamicsenergyDynamicssystem.​energyDynamicsFormulation of energy balance
TemperatureT_start Wall temperature start value
TemperaturedT Start value for port_b.T - port_a.T

Connectors

TypeNameDescription
HeatPort_aheatPort_a[n]Thermal port
HeatPort_aheatPort_b[n]Thermal port

Generated 2018-12-12 12:13:19 EST by MapleSim.