Moist Air Properties (MA)
Global wet air properties for units connected to the wet air network.
blockType: AcausalFoundation.MoistAir.Properties
|
Path in the library: |
.svg)
Description
Block Moist Air Properties (MA) defines the properties of humid air, which act as global parameters for all units connected to the network. The humid air mixture consists of dry air, water vapor and optional impurity gas or water droplets. Carbon dioxide is used By default as an impurity gas.
It is assumed that dry air, water vapor and impurity gas are semi-ideal gases. Pressure, temperature and density obey the ideal gas law. Other properties are functions of temperature. You specify them as one-dimensional arrays corresponding to a vector Temperature vector.
A block can be connected to each topologically different humid air network in the diagram Moist Air Properties (MA). If such a block is not connected to the network, then the blocks in this network use the properties of moist air corresponding to the values of the block parameters Moist Air Properties (MA) By default.
Ports
Conserving
#
A
—
connection port
`humid air
Details
The humid air port, connects the unit to the humid air network. You can connect it to any point on the circuit. When you connect a unit Moist Air Properties (MA), Engee automatically identifies the humid air units connected to a particular circuit and transfers the humid air properties to all units in the circuit.
| Program usage name |
|
Parameters
Dry Air
#
Maximum valid pressure —
maximum allowable pressure
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 highest pressure allowed in the humid air network.
| Units |
|
| Default value |
|
| Program usage name |
|
| Evaluatable |
Yes |
#
Pressure and temperature outside valid range —
action when pressure or temperature exceeds the permissible range
None | Error
Details
Select what happens if the pressure or temperature of the humid air 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 |
|
| Default value |
|
| Program usage name |
|
| Evaluatable |
No |
#
Temperature vector —
vector of temperature values
K | degC | degF | degR | deltaK | deltadegC | deltadegF | deltadegR
Details
A vector of temperature values used to find other properties depending on temperature. The properties of dry air, water vapor, and impurity gases have the same vector of temperature values.
| Units |
|
| Default value |
|
| Program usage name |
|
| Evaluatable |
Yes |
#
Minimum valid pressure —
lowest allowable pressure
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 humid air network.
| Units |
|
| Default value |
|
| Program usage name |
|
| Evaluatable |
Yes |
#
Dry air dynamic viscosity vector —
vector of dynamic viscosity values
Pa*s | uPa*s | cP | P | N*s/m^2 | kgf*s/m^2 | reyn
Details
A vector of values of dynamic viscosity of dry air, used for a one-dimensional search in the table based on the corresponding temperature value. The size of the vector must be the same as the size of the vector of temperature values.
| Units |
|
| Default value |
|
| Program usage name |
|
| Evaluatable |
Yes |
#
Maximum valid temperature —
the highest allowable temperature
K | degC | degF | degR | deltaK | deltadegC | deltadegF | deltadegR
Details
The highest temperature allowed in the humid air network.
| Units |
|
| Default value |
|
| Program usage name |
|
| Evaluatable |
Yes |
#
Atmospheric pressure —
absolute ambient pressure
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 |
|
| Default value |
|
| Program usage name |
|
| Evaluatable |
Yes |
#
Minimum valid temperature —
the lowest allowable temperature
K | degC | degF | degR | deltaK | deltadegC | deltadegF | deltadegR
Details
The lowest temperature allowed in the humid air network.
| Units |
|
| Default value |
|
| Program usage name |
|
| Evaluatable |
Yes |
#
Atmospheric temperature —
absolute ambient temperature
K | degC | degF | degR | deltaK | deltadegC | deltadegF | deltadegR
Details
The absolute ambient temperature.
| Units |
|
| Default value |
|
| Program usage name |
|
| Evaluatable |
Yes |
#
Dry air specific enthalpy vector —
vector of specific enthalpy values
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 dry air, used for a one-dimensional search in the table based on the corresponding temperature value. The size of the vector should be the same as the size of the vector of temperature values.
| Units |
|
| Default value |
|
| Program usage name |
|
| Evaluatable |
Yes |
#
Dry air thermal conductivity vector —
the vector of thermal conductivity values
W/(m*K) | mW/(m*K) | Btu_IT/(hr*ft*deltadegR)
Details
A vector of values of thermal conductivity of dry air, which will be used for a one-dimensional search in the table for the corresponding temperature value. The size of the vector should be the same as the size of the vector of temperature values.
| Units |
|
| Default value |
|
| Program usage name |
|
| Evaluatable |
Yes |
#
Dry air specific gas constant —
the ratio of the universal gas constant to the molar mass of dry air
J/(kg*K) | kJ/(kg*K) | cal/(kg*K) | kcal/(kg*K) | cal/(g*K) | kcal/(g*K) | Btu_IT/(lbm*deltadegR)
Details
The ratio of the universal gas constant to the molar mass of dry air.
| Units |
|
| Default value |
|
| Program usage name |
|
| Evaluatable |
Yes |
Water Vapor
#
Water vapor specific enthalpy vector —
vector of specific enthalpy values
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 water vapor, used for a one-dimensional search in the table based on the corresponding temperature value. The size of the vector must be the same as the size of the vector of temperature values. The properties of dry air, water vapor, and impurity gases have the same vector of temperature values.
| Units |
|
| Default value |
|
| Program usage name |
|
| Evaluatable |
Yes |
# Enable entrained water droplets — water droplet modeling option
Details
Select this option to simulate water droplets trapped in a moist air mixture. If you uncheck this box, the model will ignore any non-zero values of water droplets in the parameters and input data of the units connected to the network. Block equations listed on the library block documentation pages Moist Air, replace the values of water droplets in calculations by 0.
| Default value |
|
| Program usage name |
|
| Evaluatable |
No |
#
Water vapor dynamic viscosity vector —
vector of dynamic viscosity values
Pa*s | uPa*s | cP | P | N*s/m^2 | kgf*s/m^2 | reyn
Details
A vector of values of the dynamic viscosity of water vapor, used for a one-dimensional search in the table based on the corresponding temperature value. The size of the vector must be the same as the size of the vector of temperature values. The properties of dry air, water vapor, and impurity gases have the same vector of temperature values.
| Units |
|
| Default value |
|
| Program usage name |
|
| Evaluatable |
Yes |
#
Water vapor diffusivity in air —
smoothing coefficient for reverse flows
m^2/s | mm^2/s | in^2/s | ft^2/s | St | cSt | newt
Details
The coefficient for the diffusion flow of water vapor in a moist air mixture due to the difference in the concentration of water vapor. When the mixture flow is reversed, the mass flow rate of water vapor at the ports smoothly transitions from an upstream value to a downstream value based on the diffusion coefficient.
| Units |
|
| Default value |
|
| Program usage name |
|
| Evaluatable |
Yes |
#
Water specific enthalpy of vaporization vector —
the vector of values of the specific enthalpy of vaporization
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 vector of values of the difference between the specific enthalpy of saturated water vapor and the specific enthalpy of saturated liquid water as a function of temperature, used for a one-dimensional search in the table. The size of the vector must be the same as the size of the vector of temperature values. The properties of dry air, water vapor, and impurity gases have the same vector of temperature values.
| Units |
|
| Default value |
|
| Program usage name |
|
| Evaluatable |
Yes |
#
Water vapor specific gas constant —
the universal gas constant divided by the molar mass of water vapor
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 water vapor.
| Units |
|
| Default value |
|
| Program usage name |
|
| Evaluatable |
Yes |
#
Water vapor thermal conductivity vector —
the vector of thermal conductivity values
W/(m*K) | mW/(m*K) | Btu_IT/(hr*ft*deltadegR)
Details
A vector of values of the thermal conductivity of water vapor, used for a one-dimensional search in the table based on the corresponding temperature value. The size of the vector must be the same as the size of the vector of temperature values. The properties of dry air, water vapor, and impurity gases have the same vector of temperature values.
| Units |
|
| Default value |
|
| Program usage name |
|
| Evaluatable |
Yes |
#
Water vapor saturation pressure vector —
vector of water vapor saturation values
Pa | uPa | hPa | kPa | MPa | GPa | kgf/m^2 | kgf/cm^2 | kgf/mm^2 | mbar | bar | kbar | atm | ksi | psi | mmHg | inHg
Details
Vector of water vapor saturation values depending on temperature for use in one-dimensional tables.
Humid air becomes saturated when the partial pressure of water vapor is equal to the saturation pressure of water vapor. Therefore, condensation may occur. The size of the vector must be the same as the size of the vector of temperature values.
The properties of dry air, water vapor, and impurity gases have the same vector of temperature values.
| Units |
|
| Default value |
|
| Program usage name |
|
| Evaluatable |
Yes |
Trace Gas
#
Trace gas thermal conductivity vector —
the vector of thermal conductivity values
W/(m*K) | mW/(m*K) | Btu_IT/(hr*ft*deltadegR)
Details
The vector of the values of the thermal conductivity of the impurity gas, which will be used for a one-dimensional search in the table for the corresponding temperature value. The size of the vector must be the same as the size of the vector of temperature values. The properties of dry air, water vapor, and impurity gases have the same vector of temperature values.
Dependencies
To use this parameter, set for the parameter Trace gas model meaning Track mass fraction and gas properties.
| Units |
|
| Default value |
|
| Program usage name |
|
| Evaluatable |
Yes |
#
Trace gas dynamic viscosity vector —
vector of dynamic viscosity values
Pa*s | uPa*s | cP | P | N*s/m^2 | kgf*s/m^2 | reyn
Details
The vector of values of the dynamic viscosity of the impurity gas, used for a one-dimensional search in the table based on the corresponding temperature value. The size of the vector must be the same as the size of the vector of temperature values. The properties of dry air, water vapor, and impurity gases have the same vector of temperature values.
Dependencies
To use this parameter, set for the parameter Trace gas model meaning Track mass fraction and gas properties.
| Units |
|
| Default value |
|
| Program usage name |
|
| Evaluatable |
Yes |
#
Trace gas diffusivity in air —
smoothing coefficient for reverse flows
m^2/s | mm^2/s | in^2/s | ft^2/s | St | cSt | newt
Details
The coefficient for the diffusion flow of impurity gases in a moist air mixture due to the difference in the concentration of impurity gases. When the mixture flow is reversed, the mass flow rate of the impurity gas at the ports smoothly transitions from an upstream value to a downstream value based on the diffusion coefficient.
Dependencies
To use this parameter, set for the parameter Trace gas model meaning Track mass fraction only or Track mass fraction and gas properties.
| Units |
|
| Default value |
|
| Program usage name |
|
| Evaluatable |
Yes |
#
Trace gas model —
a method for modeling impurity gases in an air mixture
None | Track mass fraction only | Track mass fraction and gas properties
Details
Choose how the block models the amount of impurity gases in the air mixture.:
-
None— there are no gas impurities. A moist air mixture consists only of dry air and water vapor. Any non-zero values of the impurity gas level in the parameters and target variables of the units connected to the circuit are ignored. All connections to impurity gas source blocks are also ignored in the model. Thus, you do not need to change the model depending on the choice of impurity gas modeling. -
Track mass fraction only— the level of impurity gases may be non-zero and may change during the simulation process. However, it is assumed that the amount of impurity gases is small enough to have negligible effect on the properties of the liquid in the moist air mixture. -
Track mass fraction and gas properties— the level of impurity gas may be non-zero and may change during simulation. The liquid properties of a moist air mixture depend on the amount of impurity gas in the mixture.
| Values |
|
| Default value |
|
| Program usage name |
|
| Evaluatable |
No |
#
Trace gas specific enthalpy vector —
vector of specific enthalpy values
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 impurity gases, which will be used for a one-dimensional search in the table based on the corresponding temperature value. The size of the vector must be the same as the size of the vector of temperature values. The properties of dry air, water vapor, and impurity gases have the same vector of temperature values.
Dependencies
To use this parameter, set for the parameter Trace gas model meaning Track mass fraction and gas properties.
| Units |
|
| Default value |
|
| Program usage name |
|
| Evaluatable |
Yes |
#
Trace gas specific gas constant —
the ratio of the universal gas constant to the molar mass of the impurity 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 ratio of the universal gas constant to the molar mass of the impurity gas.
Dependencies
To use this parameter, set for the parameter Trace gas model meaning Track mass fraction only or Track mass fraction and gas properties.
| Units |
|
| Default value |
|
| Program usage name |
|
| Evaluatable |
Yes |