modelBasicHX

Simple heat exchanger model
Diagram of BasicHXOpen the diagram
▶ Check in your browser

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
SI.LengthlengthLength of flow path for both fluids
IntegernNodes2Spatial segmentation
Booleanuse_HeatTransfertrue= true to use the HeatTransfer_1/_2 model
SI.Areaarea_h(area_h_1 + area_h_2)/2Heat transfer area
SI.Massm_wallrho_wall*area_h*s_wallWall mass
General › Fluid 1
Modelica.Fluid.Types.ModelStructuremodelStructure_1Types.ModelStructure.av_vbDetermines whether flow or volume models are present at the ports
SI.AreacrossArea_1Cross sectional area
SI.Lengthperimeter_1Flow channel perimeter
SI.Areaarea_h_1Heat transfer area
Modelica.Fluid.Types.Roughnessroughness_12.5e-5Absolute roughness of pipe (default = smooth steel pipe)
General › Fluid 2
Modelica.Fluid.Types.ModelStructuremodelStructure_2Types.ModelStructure.av_vbDetermines whether flow or volume models are present at the ports
SI.AreacrossArea_2Cross sectional area
SI.Lengthperimeter_2Flow channel perimeter
SI.Areaarea_h_2Heat transfer area
Modelica.Fluid.Types.Roughnessroughness_22.5e-5Absolute roughness of pipe (default = smooth steel pipe)
Wall properties
SI.Lengths_wallWall thickness
SI.ThermalConductivityk_wallThermal conductivity of wall material
General › Wall properties
SI.SpecificHeatCapacityc_wallSpecific heat capacity of wall material
SI.Densityrho_wallDensity of wall material
Assumptions
BooleanallowFlowReversalsystem.allowFlowReversalAllow flow reversal, false restricts to design direction (port_a -> port_b)
Assumptions › Dynamics
Modelica.Fluid.Types.DynamicsenergyDynamicssystem.energyDynamicsFormulation of energy balance
Modelica.Fluid.Types.DynamicsmassDynamicssystem.massDynamicsFormulation of mass balance
Modelica.Fluid.Types.DynamicsmomentumDynamicssystem.momentumDynamicsFormulation of momentum balance, if pressureLoss options available
Initialization › Wall
SI.TemperatureTwall_startStart value of wall temperature
SI.TemperatureDifferencedTStart value for pipe_1.T - pipe_2.T
Initialization
Booleanuse_T_starttrueUse T_start if true, otherwise h_start
Initialization › Fluid 1
Medium_1.AbsolutePressurep_a_start1Medium_1.p_defaultStart value of pressure
Medium_1.AbsolutePressurep_b_start1Medium_1.p_defaultStart value of pressure
Medium_1.TemperatureT_start_1if use_T_start then Medium_1.T_default else Medium_1.temperature_phX((p_a_start1 + p_b_start1)/2, h_start_1, X_start_1)Start value of temperature
Medium_1.SpecificEnthalpyh_start_1if use_T_start then Medium_1.specificEnthalpy_pTX((p_a_start1 + p_b_start1)/2, T_start_1, X_start_1) else Medium_1.h_defaultStart value of specific enthalpy
Medium_1.MassFraction[Medium_1.nX]X_start_1Medium_1.X_defaultStart value of mass fractions m_i/m
Medium_1.MassFlowRatem_flow_start_1system.m_flow_startStart value of mass flow rate
Initialization › Fluid 2
Medium_2.AbsolutePressurep_a_start2Medium_2.p_defaultStart value of pressure
Medium_2.AbsolutePressurep_b_start2Medium_2.p_defaultStart value of pressure
Medium_2.TemperatureT_start_2if use_T_start then Medium_2.T_default else Medium_2.temperature_phX((p_a_start2 + p_b_start2)/2, h_start_2, X_start_2)Start value of temperature
Medium_2.SpecificEnthalpyh_start_2if use_T_start then Medium_2.specificEnthalpy_pTX((p_a_start2 + p_b_start2)/2, T_start_2, X_start_2) else Medium_2.h_defaultStart value of specific enthalpy
Medium_2.MassFraction[Medium_2.nX]X_start_2Medium_2.X_defaultStart value of mass fractions m_i/m
Medium_2.MassFlowRatem_flow_start_2system.m_flow_startStart value of mass flow rate

Connectors

TypeNameDefaultDescription
Modelica.Fluid.Interfaces.FluidPort_bport_b1
Modelica.Fluid.Interfaces.FluidPort_aport_a1
Modelica.Fluid.Interfaces.FluidPort_bport_b2
Modelica.Fluid.Interfaces.FluidPort_aport_a2

Components

TypeNameDefaultDescription
Modelica.Fluid.SystemsystemSystem properties
SI.HeatFlowRateQ_flow_1Total heat flow rate of pipe 1
SI.HeatFlowRateQ_flow_2Total heat flow rate of pipe 2
BaseClasses.WallConstPropswall
Pipes.DynamicPipepipe_1
Pipes.DynamicPipepipe_2

Contents

NameDescription
Medium_1
Medium_2
HeatTransfer_1
HeatTransfer_2
FlowModel_1
FlowModel_2