Thermodynamic Properties Sensor (MA)

Measurement of specific enthalpy, density, specific heat capacity at constant pressure and specific entropy in a network of moist air.

blockType: AcausalFoundation.MoistAir.Sensors.ThermodynamicProperties

Path in the library:

/Physical Modeling/Fundamental/Moist Air/Sensors/Thermodynamic Properties Sensor (MA)

Description

The Thermodynamic Properties Sensor (MA) unit is an ideal sensor that measures specific enthalpy, density, specific heat capacity at constant pressure and specific entropy in a network of moist air. There is no mass or energy flow through the sensor.

The unit measures these thermodynamic properties in a node connected to port A. With the Measurements based on parameters you can choose to output these measurements: normalised to the mass of the entire humid air mixture or to the mass of only dry air and gas impurities (without water vapour mass).

The specific entropy reference value used to calibrate the sensor is 0 for each component of the moist air mixture at atmospheric pressure and atmospheric temperature.

Ports

Conserving

# A — sensor input
`humid air

Details

Humid air port, corresponds to the input to the sensor. Connect this port to the node in the humid air network where you want to measure the thermodynamic properties.

Program usage name

port

Output

# ρ — density, kg/m³
scalar

Details

Output port for density measurement in a wet air network.

Dependencies

To use this port, select the check box for the parameters Density.

Data types	`Float64`.
Complex numbers support	No

# h — specific enthalpy, J/kg
scalar

Details

Signal output port for measuring specific enthalpy in a humid air network.

Dependencies

To use this port, select the check box for the parameters Enthalpy.

Data types	`Float64`.
Complex numbers support	No

# cp — specific heat capacity at constant pressure, J/(kg⋅K)
scalar

Details

Signal output port for measuring the specific heat capacity of moist air at constant pressure.

Dependencies

To use this port, select the check box for the parameters Specific heat.

Data types	`Float64`.
Complex numbers support	No

# s — specific entropy, J/(kg⋅K)
scalar

Details

Signal output port for measuring the specific entropy of moist air.

Dependencies

To use this port, select the checkbox for the parameters Entropy.

Data types	`Float64`.
Complex numbers support	No

Parameters

# Measurements based on — measurement output option
Mixture air | Dry air and trace gas

Details

Select the measurement output option: normalised to the mass of the entire moist air mixture or to the mass of dry air and gas impurities only (without moisture).

Mixture air - for each thermodynamic property, the measured mass of this property in the volume of moist air is divided by the mass of the moist air mixture itself.
Dry air and trace gas - for each thermodynamic property, the measured mass of that property in the volume of moist air is divided by the mass of dry air and gas impurities (excluding the mass of water vapour).

Values	`Mixture air` \| `Dry air and trace gas`
Default value	`Mixture air`
Program usage name	`measurement_mass_type`
Evaluatable	No

# Enthalpy — switching on the output port for specific enthalpy measurement

Details

Checking this box enables the h output port to measure the specific enthalpy of an air mixture.

Default value	`false (switched off)`
Program usage name	`measure_enthalpy`
Evaluatable	No

# Enthalpy reference state — select the reference state for the specific enthalpy output signal
As provided in Moist Air Properties (MA) block | 0 degC with water as vapor | 0 degC with water as liquid

Details

Select the reference state for the specific enthalpy output signal:

As provided in Moist Air Properties (MA) block - The sensor outputs the enthalpy of the mixture based directly on the enthalpy vectors provided in the Moist Air Properties (MA) block , without corrections. This option is for informational purposes only, as library blocks use corrected values.
0 degC with water as vapor - The sensor outputs the enthalpy of the mixture corrected to a baseline of 0 kJ/kg at 0 °C. These are the values used in the library blocks and displayed in the simulation log.
0 degC with water as liquid - The sensor outputs the mixture enthalpy corrected so that the liquid water has an initial state of 0 kJ/kg at 0 °C. In this case, the enthalpy of water vapour includes the enthalpy of vaporisation or latent heat in the initial state. These are the values used in wall condensation calculations.

Dependencies

To use this parameter, select the checkbox Enthalpy.

Values	`As provided in Moist Air Properties (MA) block` \| `0 degC with water as vapor` \| `0 degC with water as liquid`
Default value	`As provided in Moist Air Properties (MA) block`
Program usage name	`enthalpy_reference_state`
Evaluatable	No

# Density — switching on the output port for density measurement

Details

Checking this box enables the ρ output port to measure the density of the air mixture.

Default value	`true (switched on)`
Program usage name	`measure_density`
Evaluatable	No

# Specific heat — switching on the output port for specific heat measurement

Details

Checking this box enables the cp output port to measure the specific heat capacity of an air mixture.

Default value	`false (switched off)`
Program usage name	`measure_specific_heat`
Evaluatable	No

# Entropy — switching on the output port for specific entropy measurement

Details

Checking this box enables the s output port to measure the specific entropy of the air mixture.

Default value	`false (switched off)`
Program usage name	`measure_entropy`
Evaluatable	No