Modelica.Fluid.Examples.HeatExchanger.BaseClasses

Additional models for heat exchangers

Information

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

Package Content

NameDescription
Modelica.Fluid.Examples.HeatExchanger.BaseClasses.BasicHX BasicHX Simple heat exchanger model
Modelica.Fluid.Examples.HeatExchanger.BaseClasses.WallConstProps WallConstProps Pipe wall with capacitance, assuming 1D heat conduction and constant material properties

Modelica.Fluid.Examples.HeatExchanger.BaseClasses.BasicHX 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

NameDescription
lengthLength of flow path for both fluids [m]
nNodesSpatial segmentation
Fluid 1
modelStructure_1Determines whether flow or volume models are present at the ports
replaceable package Medium_1Fluid 1
crossArea_1Cross sectional area [m2]
perimeter_1Flow channel perimeter [m]
replaceable model HeatTransfer_1Heat transfer model
area_h_1Heat transfer area [m2]
replaceable model FlowModel_1Characteristic of wall friction
roughness_1Absolute roughness of pipe (default = smooth steel pipe) [m]
Fluid 2
modelStructure_2Determines whether flow or volume models are present at the ports
replaceable package Medium_2Fluid 2
crossArea_2Cross sectional area [m2]
perimeter_2Flow channel perimeter [m]
replaceable model HeatTransfer_2Heat transfer model
area_h_2Heat transfer area [m2]
replaceable model FlowModel_2Characteristic of wall friction
roughness_2Absolute roughness of pipe (default = smooth steel pipe) [m]
Wall properties
s_wallWall thickness [m]
k_wallThermal conductivity of wall material [W/(m.K)]
c_wallSpecific heat capacity of wall material [J/(kg.K)]
rho_wallDensity of wall material [kg/m3]
Assumptions
allowFlowReversalallow flow reversal, false restricts to design direction (port_a -> port_b)
Dynamics
energyDynamicsFormulation of energy balance
massDynamicsFormulation of mass balance
momentumDynamicsFormulation of momentum balance, if pressureLoss options available
Initialization
Wall
Twall_startStart value of wall temperature [K]
dTStart value for pipe_1.T - pipe_2.T [K]
use_T_startUse T_start if true, otherwise h_start
Fluid 1
p_a_start1Start value of pressure [Pa]
p_b_start1Start value of pressure [Pa]
T_start_1Start value of temperature [K]
h_start_1Start value of specific enthalpy [J/kg]
X_start_1[Medium_1.nX]Start value of mass fractions m_i/m [kg/kg]
m_flow_start_1Start value of mass flow rate [kg/s]
Fluid 2
p_a_start2Start value of pressure [Pa]
p_b_start2Start value of pressure [Pa]
T_start_2Start value of temperature [K]
h_start_2Start value of specific enthalpy [J/kg]
X_start_2[Medium_2.nX]Start value of mass fractions m_i/m [kg/kg]
m_flow_start_2Start value of mass flow rate [kg/s]

Connectors

NameDescription
port_b1 
port_a1 
port_b2 
port_a2 
Fluid 1
replaceable package Medium_1Fluid 1
replaceable model HeatTransfer_1Heat transfer model
replaceable model FlowModel_1Characteristic of wall friction
Fluid 2
replaceable package Medium_2Fluid 2
replaceable model HeatTransfer_2Heat transfer model
replaceable model FlowModel_2Characteristic of wall friction

Modelica.Fluid.Examples.HeatExchanger.BaseClasses.WallConstProps 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

NameDescription
nSegmentation perpendicular to heat conduction
sWall thickness [m]
area_hHeat transfer area [m2]
rho_wallDensity of wall material [kg/m3]
c_wallSpecific heat capacity of wall material [J/(kg.K)]
k_wallThermal conductivity of wall material [W/(m.K)]
m[n]Distribution of wall mass [kg]
T_startWall temperature start value [K]
dTStart value for port_b.T - port_a.T [K]
Assumptions
Dynamics
energyDynamicsFormulation of energy balance

Connectors

NameDescription
heatPort_a[n]Thermal port
heatPort_b[n]Thermal port

Automatically generated Mon Sep 23 17:20:45 2013.