Modelica.Media.Examples

Demonstrate usage of property models (currently: simple tests)

Information

Examples

Physical properties for fluids are needed in so many different variants that a library can only provide models for the most common situations. With the following examples we are going to demonstrate how to use the existing packages and functions in Modelica.Media to customize these models for advanced applications. The high level functions try to abstract as much as possible form the fact that different media are based on different variables, e.g., ideal gases need pressure and temperature, while many refrigerants are based on Helmholtz functions of density and temperature, and many water properties are based on pressure and specific enthalpy. Medium properties are needed in control volumes in the dynamic state equations and in many thermodynamic state locations that are independent of the dynamic states of a control volume, e.g., at a wall temperature, an isentropic reference state or at a phase boundary. The general structure of the library is such that:

Each medium has a model called BaseProperties. BaseProperties contains the minimum set of medium properties needed in a dynamic control volume model.
Each instance of BaseProperties contains a "state" record that is an input to all the functions to compute properties. If these functions need further inputs, like e.g., the molarMass, these are accessible as constants in the package.
The simplest way to compute properties at any other reference point is to declare an instance of ThermodynamicState and use that as input to arbitrary property functions.

A small library of generic volume, pipe, pump and ambient models is provided in Modelica.Media.Examples.Tests.Components to demonstrate how fluid components should be implemented that are using Modelica.Media models. This library is also used to test all media models in Modelica.Media.Examples.Tests.MediaTestModels.

Extends from Modelica.Icons.ExamplesPackage (Icon for packages containing runnable examples).

Package Content

Name	Description
SimpleLiquidWater	Example for Water.SimpleLiquidWater medium model
IdealGasH2O	IdealGas H20 medium model
WaterIF97	WaterIF97 medium model
MixtureGases	Test gas mixtures
MoistAir	Ideal gas flue gas model
TwoPhaseWater	Extension of the StandardWater package
ReferenceAir	Examples for detailed dry air and moist air medium models
R134a	Examples for R134a
TestOnly	Examples to show the testing of media
Tests	Library to test that all media models simulate and fulfill the expected structural properties
SolveOneNonlinearEquation	Demonstrate how to solve one non-linear algebraic equation in one unknown

Modelica.Media.Examples.SimpleLiquidWater

Example for Water.SimpleLiquidWater medium model

Information

Extends from Modelica.Icons.Example (Icon for runnable examples).

Parameters

Name Description

V Volume [m3]

H_flow_ext Constant enthalpy flow rate into the volume [W]

Name	Description
V	Volume [m3]
H_flow_ext	Constant enthalpy flow rate into the volume [W]

Modelica.Media.Examples.IdealGasH2O

IdealGas H20 medium model

Information

An example for using ideal gas properties and how to compute isentropic enthalpy changes. The function that is implemented is approximate, but usually very good: the second medium record medium2 is given to compare the approximation.

Extends from Modelica.Icons.Example (Icon for runnable examples).

Modelica.Media.Examples.WaterIF97

WaterIF97 medium model

Information

Extends from Modelica.Icons.Example (Icon for runnable examples).

Parameters

Name Description

dV Fixed time derivative of volume [m3/s]

m_flow_ext Fixed mass flow rate into volume [kg/s]

H_flow_ext Fixed enthalpy flow rate into volume [W]

Name	Description
dV	Fixed time derivative of volume [m3/s]
m_flow_ext	Fixed mass flow rate into volume [kg/s]
H_flow_ext	Fixed enthalpy flow rate into volume [W]

Modelica.Media.Examples.MixtureGases

Test gas mixtures

Information

Extends from Modelica.Icons.Example (Icon for runnable examples).

Parameters

Name Description

V Fixed size of volume 1 and volume 2 [m3]

m_flow_ext Fixed mass flow rate in to volume 1 and in to volume 2 [kg/s]

H_flow_ext Fixed enthalpy flow rate in to volume and in to volume 2 [W]

Name	Description
V	Fixed size of volume 1 and volume 2 [m3]
m_flow_ext	Fixed mass flow rate in to volume 1 and in to volume 2 [kg/s]
H_flow_ext	Fixed enthalpy flow rate in to volume and in to volume 2 [W]

Modelica.Media.Examples.MoistAir

Ideal gas flue gas model

Information

Extends from Modelica.Icons.Example (Icon for runnable examples).

Parameters

Name Description

MMx[2] Vector of molar masses (consisting of dry air and of steam) [kg/mol]

Name	Description
MMx[2]	Vector of molar masses (consisting of dry air and of steam) [kg/mol]

Automatically generated Mon Sep 23 17:20:53 2013.