Gas Properties (G)
Global gas properties for units connected to the gas network.
blockType: AcausalFoundation.Gas.Properties
Path in the library:
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Description
Block Gas Properties (G) defines the properties of the gas, which act as global parameters for all units connected to the network. The default gas is dry air.
A block can be connected to each topologically different gas network on the model. Gas Properties (G). If such a block is not connected to the network, then the blocks in this network use the properties of the gas corresponding to the values of the block parameters. Gas Properties (G) by default.
Block Gas Properties (G) allows you to choose between three models of gas properties: ideal gas, semi-ideal gas and real gas. Three models of gas properties provide a compromise between speed and accuracy of modeling. They also provide a step-by-step workflow: you start with a simple model that requires minimal information about the working gas, and then build the model when more detailed data about the properties of the gas becomes available. The following table shows the information that must be specified for each of the three gas property models.
| A model of gas properties | Physical properties | |
|---|---|---|
The ideal gas |
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Universal gas constant |
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Compressibility factor, |
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Base temperature |
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Specific enthalpy at the base temperature |
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Specific heat capacity at constant pressure, |
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Dynamic viscosity |
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Thermal conductivity |
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Semi-ideal gas |
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Universal gas constant |
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Compressibility factor |
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Specific enthalpy vector |
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Vector of specific heat capacity at constant pressure |
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Dynamic viscosity vector |
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The vector of thermal conductivity |
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Temperature vector |
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Real gas |
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Density table |
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Table of specific entropy |
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Specific enthalpy table |
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Table of specific heat at constant pressure |
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Dynamic viscosity table |
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Thermal conductivity table |
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Table of the isothermal volumetric compression module, |
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Table of isobaric thermal expansion coefficients, |
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Temperature vector |
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Pressure vector |
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For a semi-ideal gas, the caloric and transport properties are functions of temperature. They are defined as one-dimensional arrays corresponding to Temperature vector. For a real gas, all properties are functions of temperature and pressure. They are defined as two-dimensional arrays in which the strings correspond to Temperature vector, and the columns – Pressure vector.
Ports
Conserving
#
A
—
connection port
gas
Details
The gas port connects the unit to the gas network. You can connect it to any point on the circuit. When you connect the unit Gas Properties (G)*Engee* automatically identifies gas units connected to a specific circuit and transmits the properties of the gas to all units in the circuit.
| Program usage name |
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Parameters
Physical Properties
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Gas specification —
choosing a gas property model
Perfect | Semiperfect | Real
Details
Choose a model of gas properties that determines the level of idealization:
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Perfect— ideal gas. -
Semiperfect— semi-ideal gas. -
Real— real gas.
The gas properties model defines a set of physical properties and parameters that must be specified for the working gas.
| Values |
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| Default value |
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| Program usage name |
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| Evaluatable |
No |
#
Specific gas constant —
universal gas constant for ideal or semi-ideal gas
J/(kg*K) | kJ/(kg*K) | cal/(kg*K) | kcal/(kg*K) | cal/(g*K) | kcal/(g*K) | Btu_IT/(lbm*deltadegR)
Details
The universal gas constant divided by the molar mass of the gas.
Dependencies
To use this parameter, set for the parameter Gas specification meaning Perfect or Semiperfect.
| Units |
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| Default value |
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| Program usage name |
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| Evaluatable |
Yes |
# Compressibility factor — compression ratio for ideal or semi-ideal gas
Details
The compressibility coefficient, which takes into account the deviation from the ideal gas law. During the simulation, it is assumed that it is constant.
Dependencies
To use this parameter, set for the parameter Gas specification meaning Perfect or Semiperfect.
| Default value |
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| Program usage name |
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| Evaluatable |
Yes |
#
Reference temperature for gas properties —
the base temperature for gas properties for an ideal gas
K | degC | degF | degR | deltaK | deltadegC | deltadegF | deltadegR
Details
The temperature for which the properties of an ideal gas are set.
Dependencies
To use this parameter, set for the parameter Gas specification meaning Perfect.
| Units |
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| Default value |
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| Program usage name |
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| Evaluatable |
Yes |
#
Specific enthalpy at reference temperature —
specific enthalpy at the base temperature for an ideal gas
J/kg | kJ/kg | cal/kg | kcal/kg | mm^2/s^2 | cm^2/s^2 | m^2/s^2 | km^2/s^2 | km^2/hr^2 | in^2/s^2 | ft^2/s^2 | ft^2/min^2 | mi^2/s^2 | mi^2/hr^2 | Pa/(kg/m^3) | psi/(lbm/ft^3) | bar/(kg/m^3)
Details
The specific enthalpy of an ideal gas at the base temperature.
Dependencies
To use this parameter, set for the parameter Gas specification meaning Perfect.
| Units |
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| Default value |
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| Program usage name |
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| Evaluatable |
Yes |
#
Specific heat at constant pressure —
specific heat capacity at constant pressure for an ideal gas
J/(kg*K) | kJ/(kg*K) | cal/(kg*K) | kcal/(kg*K) | cal/(g*K) | kcal/(g*K) | Btu_IT/(lbm*deltadegR)
Details
The specific heat capacity of an ideal gas at constant pressure.
Dependencies
To use this parameter, set for the parameter Gas specification meaning Perfect.
| Units |
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| Default value |
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| Program usage name |
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| Evaluatable |
Yes |
#
Dynamic viscosity —
dynamic viscosity for an ideal gas
Pa*s | uPa*s | cP | P | N*s/m^2 | kgf*s/m^2 | reyn
Details
Dynamic viscosity of an ideal gas.
Dependencies
To use this parameter, set for the parameter Gas specification meaning Perfect.
| Units |
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| Default value |
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| Program usage name |
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| Evaluatable |
Yes |
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Thermal conductivity —
thermal conductivity of an ideal gas
W/(m*K) | mW/(m*K) | Btu_IT/(hr*ft*deltadegR)
Details
Thermal conductivity of an ideal gas.
Dependencies
To use this parameter, set for the parameter Gas specification meaning Perfect.
| Units |
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| Default value |
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| Program usage name |
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| Evaluatable |
Yes |
#
Temperature vector —
temperature vector for semi-ideal or real gas
K | degC | degF | degR | deltaK | deltadegC | deltadegF | deltadegR
Details
A vector of gas temperature values that will be used to search the table for other gas properties.
The block allows you to easily switch between models of gas properties without having to change the parameter values. Although the parameter name is the same for semi-ideal and real gas, the values are independent of each other. The block stores them separately. Thus, the block can store different search tables for semi-ideal and real gas.
Dependencies
To use this parameter, set for the parameter Gas specification meaning Semiperfect or Real.
| Units |
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| Default value |
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| Program usage name |
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| Evaluatable |
Yes |
#
Specific enthalpy vector —
vector of specific enthalpy values for a semi-ideal gas
J/kg | kJ/kg | cal/kg | kcal/kg | mm^2/s^2 | cm^2/s^2 | m^2/s^2 | km^2/s^2 | km^2/hr^2 | in^2/s^2 | ft^2/s^2 | ft^2/min^2 | mi^2/s^2 | mi^2/hr^2 | Pa/(kg/m^3) | psi/(lbm/ft^3) | bar/(kg/m^3)
Details
A vector of values of the specific enthalpy of a semi-ideal gas to be searched in a one-dimensional table based on the corresponding temperature value. The size of the vector must be the same as the size of the temperature vector.
Dependencies
To use this parameter, set for the parameter Gas specification meaning Semiperfect.
| Units |
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| Default value |
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| Program usage name |
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| Evaluatable |
Yes |
#
Specific heat at constant pressure vector —
vector of values of specific heat at constant pressure for a semi-ideal gas
J/(kg*K) | kJ/(kg*K) | cal/(kg*K) | kcal/(kg*K) | cal/(g*K) | kcal/(g*K) | Btu_IT/(lbm*deltadegR)
Details
A vector of specific heat values at constant pressure values to be searched in a one-dimensional table based on the corresponding temperature value. The size of the vector must be the same as the size of the temperature vector.
Dependencies
To use this parameter, set for the parameter Gas specification meaning Semiperfect.
| Units |
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| Default value |
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| Program usage name |
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| Evaluatable |
Yes |
#
Dynamic viscosity vector —
vector of dynamic viscosity values for a semi-ideal gas
Pa*s | uPa*s | cP | P | N*s/m^2 | kgf*s/m^2 | reyn
Details
A vector of gas dynamic viscosity values to be searched in a one-dimensional table by the corresponding temperature value. The size of the vector must be the same as the size of the temperature vector.
Dependencies
To use this parameter, set for the parameter Gas specification meaning Semiperfect.
| Units |
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| Default value |
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| Program usage name |
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| Evaluatable |
Yes |
#
Thermal conductivity vector —
the vector of thermal conductivity values for a semi-ideal gas
W/(m*K) | mW/(m*K) | Btu_IT/(hr*ft*deltadegR)
Details
A vector of values of the thermal conductivity of a gas to be searched in a one-dimensional table by the corresponding temperature value. The size of the vector must be the same as the size of the temperature vector.
Dependencies
To use this parameter, set for the parameter Gas specification meaning Semiperfect.
| Units |
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| Default value |
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| Program usage name |
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| Evaluatable |
Yes |
#
Pressure vector —
vector of pressure values for real gas
Pa | uPa | hPa | kPa | MPa | GPa | kgf/m^2 | kgf/cm^2 | kgf/mm^2 | mbar | bar | kbar | atm | ksi | psi | mmHg | inHg
Details
A vector of gas pressure values that will be used together with a vector of temperature values to search for other gas properties in a two-dimensional table.
Dependencies
To use this parameter, set for the parameter Gas specification meaning Real.
| Units |
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| Default value |
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| Program usage name |
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| Evaluatable |
Yes |
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Density table —
table of density values for real gas
kg/m^3 | g/m^3 | g/cm^3 | g/mm^3 | lbm/ft^3 | lbm/gal | lbm/in^3
Details
A matrix of gas density values for searching in a two-dimensional table by pressure and temperature. The size of the matrix should correspond to the dimensions of the pressure and temperature vectors. The table rows correspond to the parameter values Temperature vector, and the columns correspond to the values Pressure vector.
Dependencies
To use this parameter, set for the parameter Gas specification meaning Real.
| Units |
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| Default value |
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| Program usage name |
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| Evaluatable |
Yes |
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Specific entropy table —
table of specific entropy values for real gas
J/(kg*K) | kJ/(kg*K) | cal/(kg*K) | kcal/(kg*K) | cal/(g*K) | kcal/(g*K) | Btu_IT/(lbm*deltadegR)
Details
A matrix of specific entropy values to be searched in a two-dimensional table based on pressure and temperature. The size of the matrix should correspond to the dimensions of the pressure and temperature vectors. The table rows correspond to the parameter values Temperature vector, and the columns correspond to the values Pressure vector.
Dependencies
To use this parameter, set for the parameter Gas specification meaning Real.
| Units |
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| Default value |
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| Program usage name |
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| Evaluatable |
Yes |
#
Specific enthalpy table —
table of specific enthalpy values for real gas
J/kg | kJ/kg | cal/kg | kcal/kg | mm^2/s^2 | cm^2/s^2 | m^2/s^2 | km^2/s^2 | km^2/hr^2 | in^2/s^2 | ft^2/s^2 | ft^2/min^2 | mi^2/s^2 | mi^2/hr^2 | Pa/(kg/m^3) | psi/(lbm/ft^3) | bar/(kg/m^3)
Details
A matrix of specific enthalpy values to search in a two-dimensional table based on pressure and temperature. The size of the matrix should correspond to the dimensions of the pressure and temperature vectors. The table rows correspond to the parameter values Temperature vector, and the columns correspond to the values Pressure vector.
Dependencies
To use this parameter, set for the parameter Gas specification meaning Real.
| Units |
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| Default value |
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| Program usage name |
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| Evaluatable |
Yes |
#
Specific heat at constant pressure table —
table of values of specific heat at constant pressure for real gas
J/(kg*K) | kJ/(kg*K) | cal/(kg*K) | kcal/(kg*K) | cal/(g*K) | kcal/(g*K) | Btu_IT/(lbm*deltadegR)
Details
A matrix of heat capacity at constant pressure values for searching in a two-dimensional table based on pressure and temperature. The size of the matrix should correspond to the dimensions of the pressure and temperature vectors. The table rows correspond to the parameter values Temperature vector, and the columns correspond to the values Pressure vector.
Dependencies
To use this parameter, set for the parameter Gas specification meaning Real.
| Units |
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| Default value |
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| Program usage name |
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| Evaluatable |
Yes |
#
Dynamic viscosity table —
table of dynamic viscosity values for real gas
Pa*s | uPa*s | cP | P | N*s/m^2 | kgf*s/m^2 | reyn
Details
A matrix of gas dynamic viscosity values for searching in a two-dimensional table by pressure and temperature. The size of the matrix should correspond to the dimensions of the pressure and temperature vectors. The table rows correspond to the parameter values Temperature vector, and the columns correspond to the values Pressure vector.
Dependencies
To use this parameter, set for the parameter Gas specification meaning Real.
| Units |
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| Default value |
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| Program usage name |
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| Evaluatable |
Yes |
#
Thermal conductivity table —
table of thermal conductivity values for real gas
W/(m*K) | mW/(m*K) | Btu_IT/(hr*ft*deltadegR)
Details
A matrix of thermal conductivity values for two-dimensional search in the pressure and temperature table. The size of the matrix should correspond to the dimensions of the pressure and temperature vectors. The table rows correspond to the parameter values Temperature vector, and the columns correspond to the values Pressure vector.
Dependencies
To use this parameter, set for the parameter Gas specification meaning Real.
| Units |
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| Default value |
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| Program usage name |
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| Evaluatable |
Yes |
#
Isothermal bulk modulus table —
table of values of the isothermal volumetric compression modulus for real gas
Pa | uPa | hPa | kPa | MPa | GPa | kgf/m^2 | kgf/cm^2 | kgf/mm^2 | mbar | bar | kbar | atm | ksi | psi | mmHg | inHg
Details
A matrix of values of the isothermal volume compression module for a two-dimensional search in a table based on pressure and temperature. The size of the matrix should correspond to the dimensions of the pressure and temperature vectors. The table rows correspond to the parameter values Temperature vector, and the columns correspond to the values Pressure vector.
Dependencies
To use this parameter, set for the parameter Gas specification meaning Real.
| Units |
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| Default value |
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| Program usage name |
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| Evaluatable |
Yes |
#
Isobaric thermal expansion coefficient table —
table of values of isobaric thermal expansion coefficients for real gas
1/K | 1/degR | 1/deltaK | 1/deltadegC | 1/deltadegF | 1/deltadegR
Details
A matrix of values of the coefficient of isobaric thermal expansion for searching in a two-dimensional table by pressure and temperature. The size of the matrix should correspond to the dimensions of the pressure and temperature vectors. The table rows correspond to the parameter values Temperature vector, and the columns correspond to the values Pressure vector.
Dependencies
To use this parameter, set for the parameter Gas specification meaning Real.
| Units |
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| Default value |
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| Program usage name |
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| Evaluatable |
Yes |
Parameters
#
Valid temperature range parameterization —
a method for setting an acceptable temperature range for a semi-ideal gas
Range of gas property vectors | Specified minimum and maximum temperatures
Details
Select how the unit sets the acceptable temperature range.:
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Range of gas property vectors— the minimum and maximum parameter values are used Temperature vector. -
Specified minimum and maximum temperatures— parameter values are used Minimum valid temperature and Maximum valid temperature.
Dependencies
To use this parameter, set for the parameter Gas specification meaning Semiperfect.
| Values |
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| Default value |
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| Program usage name |
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| Evaluatable |
No |
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Valid pressure-temperature region parameterization —
a method for setting the allowable pressure and temperature range for a real gas
Range of gas property tables | Specified minimum and maximum values | Validity matrix
Details
Select how the unit sets the allowable pressure and temperature range.:
-
Range of gas property tables— the minimum and maximum parameter values are used Temperature vector and Pressure vector. -
Specified minimum and maximum values— parameter values are used Minimum valid temperature, Maximum valid temperature, Minimum valid pressure and Maximum valid pressure . -
Validity matrix— use the parameter Pressure-temperature validity matrix to specify valid pressure-temperature pairs.
Dependencies
To use this parameter, set for the parameter Gas specification meaning Real.
| Values |
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| Default value |
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| Program usage name |
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| Evaluatable |
No |
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Minimum valid temperature —
minimum allowable temperature for ideal, semi-ideal or real gas
K | degC | degF | degR | deltaK | deltadegC | deltadegF | deltadegR
Details
The lowest temperature allowed in the gas network.
For semi-ideal or real gas, the minimum and maximum parameter values can be used. Temperature vector as an acceptable temperature range instead of specifying this parameter.
| Units |
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| Default value |
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| Program usage name |
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| Evaluatable |
Yes |
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Maximum valid temperature —
maximum allowable temperature for ideal, semi-ideal or real gas
K | degC | degF | degR | deltaK | deltadegC | deltadegF | deltadegR
Details
The highest temperature allowed in the gas network.
For semi-ideal or real gas, the minimum and maximum parameter values can be used. Temperature vector as an acceptable temperature range instead of specifying this parameter.
| Units |
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| Default value |
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| Program usage name |
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| Evaluatable |
Yes |
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Minimum valid pressure —
minimum allowable pressure for ideal, semi-ideal or real gas
Pa | uPa | hPa | kPa | MPa | GPa | kgf/m^2 | kgf/cm^2 | kgf/mm^2 | mbar | bar | kbar | atm | ksi | psi | mmHg | inHg
Details
The lowest allowable pressure in the gas network.
For a real gas, you can use the minimum and maximum values of the pressure vector as an acceptable pressure range instead of specifying this parameter.
| Units |
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| Default value |
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| Program usage name |
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| Evaluatable |
Yes |
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Maximum valid pressure —
maximum allowable pressure for ideal, semi-ideal or real gas
Pa | uPa | hPa | kPa | MPa | GPa | kgf/m^2 | kgf/cm^2 | kgf/mm^2 | mbar | bar | kbar | atm | ksi | psi | mmHg | inHg
Details
The maximum allowable pressure in the gas network.
For a real gas, you can use the minimum and maximum values of the pressure vector as an acceptable pressure range instead of specifying this parameter.
| Units |
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| Default value |
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| Program usage name |
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| Evaluatable |
Yes |
# Pressure-temperature validity matrix — pressure and temperature tolerance matrix for real gas
Details
A matrix of tolerance indicators, where the rows correspond to the parameter value Temperature vector , and the columns — Pressure vector. The tolerance indicator 1 for acceptable pressure-temperature pairs and 0 for unacceptable pressure-temperature pairs.
Dependencies
To use this parameter, set for the parameter Valid pressure-temperature region parameterization meaning Validity matrix.
| Default value |
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| Program usage name |
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| Evaluatable |
Yes |
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Atmospheric pressure —
atmospheric pressure for ideal, semi-ideal or real gas
Pa | uPa | hPa | kPa | MPa | GPa | kgf/m^2 | kgf/cm^2 | kgf/mm^2 | mbar | bar | kbar | atm | ksi | psi | mmHg | inHg
Details
Absolute ambient pressure.
| Units |
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| Default value |
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| Program usage name |
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| Evaluatable |
Yes |
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Pressure and temperature outside valid range —
notification when pressure or temperature values exceed the permissible range
None | Error
Details
Choose what happens if the pressure or temperature of the liquid exceeds the acceptable range during the simulation.:
-
None— the block does not return an error if the properties fall outside the acceptable range. -
Error— the block returns an error and stops the simulation.
| Values |
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| Default value |
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| Program usage name |
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| Evaluatable |
No |
# Mach number threshold for flow reversal — Mach number threshold for flow reversal for ideal, semi-ideal or real gas
Details
The Mach number below which the flow reverses. During the flow reversal, the energy flow in the ports smoothly transitions between the upstream value and the downstream value.
| Default value |
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| Program usage name |
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| Evaluatable |
Yes |