model.thermodynamics()
Create constants and functions interfacing to a thermodynamics property package.
Syntax
Creating a thermodynamics property package feature.
model.thermodynamics().create(<ptag>,"PropertyPackage");
Setting and getting properties in a thermodynamics property package feature:
model.thermodynamics().feature(<ptag>).set(<prop>,<value>);
model.thermodynamics().feature(<ptag>).getString(<prop>);
Table 2-138: Properties supported by A thermodynamics property package.
Name
Type
Description
manager_id
String
Thermodynamics manager ID.
manager_version
String
Thermodynamics manager version.
package_id
String
Thermodynamics package ID.
package_desc
String
Thermodynamics package description. Only for display in the user interface.
model.thermodynamics().feature(<ptag>).storePersistenceData();
Calling this method after a property package feature has been created, and manager_id and package_id have been set, stores information about how the thermodynamics package was created in the COMSOL model. If the model is later opened on a computer with the thermodynamics manager installed but without the property package, this information can be used to create the required property package.
model.thermodynamics().feature(<ptag>).create(<ftag>, <type>);
Creates a thermodynamics constant, function, or flash calculation feature. Possible types are CompoundConstant, TemperatureDependentProperty, PressureDependentProperty, OnePhaseProperty, TwoPhaseProperty, and FlashCalculationProperty.
model.thermodynamics().feature(<ptag>).feature(<ftag>).set(<prop>,<value>);
model.thermodynamics().feature(<ptag>).feature(<ftag>).getString(<prop>);
model.thermodynamics().feature(<ptag>).feature(<ftag>).getStringArray(<prop>);
model.thermodynamics().feature(<ptag>).feature(<ftag>).getStringMatrix(<prop>);
Set and get properties in a thermodynamics constant, function, or flash calculation feature.
Table 2-139: Properties supported by all Thermodynamics constant, function, and flash calculation features.
Name
Type
Description
prop_basis
String
Basis (“mass” or “mole”) for evaluated properties. Only relevant for some properties.
Thermodynamics Constant Features
The thermodynamics constant features are features with the type "CompoundConstant", and are used to define constants that get their value from a thermodynamics package.
Table 2-140: Properties supported by Thermodynamics constant features.
Name
Type
Description
funcname
String
Name of constant; that is, a variable name that can be used in expressions.
compound
String
Identifier for compound in the thermodynamics property package.
property
String
Identifier for property in the thermodynamics property package.
value
String
Numerical value of constant. This value is only displayed in the user interface. When the constant is evaluated in an expression, the value is obtained by calling the thermodynamics property package.
Thermodynamics Function Features
A thermodynamics function feature defines a function that can be used to evaluate properties that depend, for example, on temperature or pressure. Different types are TemperatureDependentProperty, PressureDependentProperty, OnePhaseProperty, and TwoPhaseProperty.
Table 2-141: Properties supported by Thermodynamics function features.
Name
Type
Description
funcname
String
Name of function.
derivatives
String array
Names of partial derivatives of function.
compounds
String array
Identifiers for compounds in the thermodynamics property package.
comp_basis
String
Basis (“mass” or “mole”) for amounts of compounds. Only relevant for functions of type “OnePhaseProperty” or “TwoPhaseProperty.”
property
String
Identifier for the property to evaluate in the thermodynamics property package.
phase
String
Identifier for phase in the thermodynamics property package. Only for features of type “OnePhaseProperty.”
phase1
String
Identifier for first phase in the thermodynamics property package. Only for features of type “TwoPhaseProperty.”
phase2
String
Identifier for second phase in the thermodynamics property package. Only for features of type “TwoPhaseProperty.”
args
String matrix
Names, units, and descriptions for the function arguments. Only for display in the user interface.
unit
String
Unit of the function. Only for display in the user interface.
Functions of type TemperatureDependentProperty and PressureDependentProperty have a single argument, which is the temperature or pressure, respectively.
Functions of type OnePhaseProperty have temperature and pressure as their first two arguments. If there is more than one compound, there are additional arguments for the fraction of each compound.
Functions of type TwoPhaseProperty have temperature and pressure as their first two arguments. If there is more than one compound, there are additional arguments for the fraction of each compound in each phase.
Thermodynamics Flash Calculation Features
Thermodynamics flash calculation features are used as an interface for flash calculations, which take amounts of different compounds and two conditions (for example, temperature and pressure) as input and compute the fraction of each compound that is present in each phase.
Table 2-142: Properties supported by Thermodynamics flash calculation features.
Name
Type
Description
compounds
String array
Identifiers for compounds in the thermodynamics property package.
cond1
String
First flash condition.
cond2
String
Second flash condition.
temperature
String
Name of function evaluating the temperature (if temperature is not one of the flash conditions).
pressure
String
Name of function evaluating the pressure (if pressure is not one of the flash conditions).
inphase
String
Base name for functions evaluating presence of each phase. Function names for each phase are formed by appending _<phase> to the base name.
amounts
String
Base name for functions evaluating amount of each phase. Function names for each phase are formed by appending _<phase> to the base name.
composition
String
Base name for functions evaluating fraction of each compound in each phase. Function names are formed by appending _<phase>_<compound> to the base name.
soltype
String
Solution type (“undefined”, “normal,” or “retrograde”).
args
String matrix
Names, units, and descriptions for the function arguments. Only for display in the user interface.
phases
String array
Names of all phases. Only for display in the user interface. The phases used in the flash calculation are determined by the thermodynamics property package.
Each flash calculation feature defines a number of functions. All of the functions take the values of two flash conditions as their first two arguments, followed by arguments for the total amount of each compound.
See Also
model.func()