Modelica.Fluid.Examples.HeatExchanger.BaseClasses

Information

Package Content

Name	Description
BasicHX	Simple heat exchanger model
WallConstProps	Pipe wall with capacitance, assuming 1D heat conduction and constant material properties

Modelica.Fluid.Examples.HeatExchanger.BaseClasses.BasicHX

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

Name	Description
length	Length of flow path for both fluids [m]
nNodes	Spatial segmentation
Fluid 1
modelStructure_1	Determines whether flow or volume models are present at the ports
replaceable package Medium_1	Fluid 1
crossArea_1	Cross sectional area [m2]
perimeter_1	Flow channel perimeter [m]
replaceable model HeatTransfer_1	Heat transfer model
area_h_1	Heat transfer area [m2]
replaceable model FlowModel_1	Characteristic of wall friction
roughness_1	Absolute roughness of pipe (default = smooth steel pipe) [m]
Fluid 2
modelStructure_2	Determines whether flow or volume models are present at the ports
replaceable package Medium_2	Fluid 2
crossArea_2	Cross sectional area [m2]
perimeter_2	Flow channel perimeter [m]
replaceable model HeatTransfer_2	Heat transfer model
area_h_2	Heat transfer area [m2]
replaceable model FlowModel_2	Characteristic of wall friction
roughness_2	Absolute roughness of pipe (default = smooth steel pipe) [m]
Wall properties
s_wall	Wall thickness [m]
k_wall	Thermal conductivity of wall material [W/(m.K)]
c_wall	Specific heat capacity of wall material [J/(kg.K)]
rho_wall	Density of wall material [kg/m3]
Assumptions
allowFlowReversal	allow flow reversal, false restricts to design direction (port_a -> port_b)
Dynamics
energyDynamics	Formulation of energy balance
massDynamics	Formulation of mass balance
momentumDynamics	Formulation of momentum balance, if pressureLoss options available
Initialization
Wall
Twall_start	Start value of wall temperature [K]
dT	Start value for pipe_1.T - pipe_2.T [K]
use_T_start	Use T_start if true, otherwise h_start
Fluid 1
p_a_start1	Start value of pressure [Pa]
p_b_start1	Start value of pressure [Pa]
T_start_1	Start value of temperature [K]
h_start_1	Start 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_1	Start value of mass flow rate [kg/s]
Fluid 2
p_a_start2	Start value of pressure [Pa]
p_b_start2	Start value of pressure [Pa]
T_start_2	Start value of temperature [K]
h_start_2	Start 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_2	Start value of mass flow rate [kg/s]

Connectors

Name	Description
port_b1
port_a1
port_b2
port_a2
Fluid 1
replaceable package Medium_1	Fluid 1
replaceable model HeatTransfer_1	Heat transfer model
replaceable model FlowModel_1	Characteristic of wall friction
Fluid 2
replaceable package Medium_2	Fluid 2
replaceable model HeatTransfer_2	Heat transfer model
replaceable model FlowModel_2	Characteristic of wall friction

Modelica.Fluid.Examples.HeatExchanger.BaseClasses.WallConstProps

Information

Parameters

Name	Description
n	Segmentation perpendicular to heat conduction
s	Wall thickness [m]
area_h	Heat transfer area [m2]
rho_wall	Density of wall material [kg/m3]
c_wall	Specific heat capacity of wall material [J/(kg.K)]
k_wall	Thermal conductivity of wall material [W/(m.K)]
m[n]	Distribution of wall mass [kg]
T_start	Wall temperature start value [K]
dT	Start value for port_b.T - port_a.T [K]
Assumptions
Dynamics
energyDynamics	Formulation of energy balance

Connectors

Name	Description
heatPort_a[n]	Thermal port
heatPort_b[n]	Thermal port