Reservoir (MA)

Boundary conditions for a humid air network at constant pressure, temperature, humidity, and amount of impurity gases.

blockType: AcausalFoundation.MoistAir.Elements.Reservoir

Reservoir (MA)

Path in the library:

/Physical Modeling/Fundamental/Moist Air/Elements/Reservoir (MA)

Controlled Reservoir (MA)

Path in the library:

/Physical Modeling/Fundamental/Moist Air/Elements/Controlled Reservoir (MA)

Description

Block Reservoir (MA) It is an infinite reservoir with fixed pressure, temperature, humidity and amount of impurity gases and can set controlled boundary conditions in the humid air network. The tank and its inlet can be at atmospheric or preset pressure. Port A corresponds to the entrance to the tank. The volume of moist air inside the tank is considered infinite, so the flow is assumed to be quasi-stationary.

Moist air enters and exits the tank at the pressure set for the tank, the remaining characteristics of moist air (temperature, specific humidity, mass fraction of impurity gases and water droplets) are determined by the direction of the flow of moist air:

If moist air exits the tank, then its temperature, specific humidity, mass fraction of impurity gases and water droplets are equal to the corresponding parameters of the tank.
If moist air enters the tank, its temperature, specific humidity, mass fraction of impurity gases and water droplets are determined by the previous humid air network.

The pressure, temperature, amount of moisture, impurity gas, and water droplets in the tank are set by control signals at ports P, T, W/Tw, G, and D, respectively. The input signals are limited by their acceptable ranges. For the amount of moisture, the permissible range is from zero to saturation or 100% of water vapor. For the amount of impurity gas, the acceptable range is from zero to either the fraction remaining after water vapor, or 100% of the impurity gas.

The unit ignores parameters and scalar signals associated with impurity gas or water droplets if the unit Moist Air Properties (MA) for the parameter Trace gas model the value is set None or if the checkbox is unchecked Enable entrained water droplets accordingly.

Humidity can be measured as one of the values:

Relative humidity, ― relative humidity, parameter Reservoir relative humidity;
Specific humidity, ― specific humidity, parameter Reservoir specific humidity;
Water vapor mole fraction, ― molar fraction of water vapor, parameter Reservoir water vapor mole fraction;
Humidity ratio, ― humidity coefficient, parameter Reservoir humidity ratio;
Wet-bulb temperature, ― the temperature of the wet thermometer, the parameter Reservoir wet-bulb temperature.

You can specify the impurity gas as one of the following parameters:

Mass fraction, ― mass fraction of impurity gases, parameter Reservoir trace gas mass fraction;
Mole fraction , ― molar fraction of impurity gases, parameter Reservoir trace gas mole fraction.

The amount of moisture and impurity gas are related to each other as follows:

where

— pressure;
— universal gas constant.

Subscript indexes , and denote the properties of dry air, water vapor, and impurity gas, respectively. Subscript indicates water vapor at saturation.

The unit implicitly calculates the temperature of the wet thermometer using this equation:

where

— temperature;
— the temperature of the wet thermometer;
— specific humidity;
— mass fraction of impurity gas;
— specific saturation humidity at the temperature of a wet thermometer;
— specific enthalpy of dry air;
— specific enthalpy of dry air at the temperature of a wet thermometer;
— specific enthalpy of impurity gas;
— specific enthalpy of impurity gas at the temperature of a wet thermometer;
— specific enthalpy of water vapor;
— specific enthalpy of water vapor at the temperature of a wet thermometer;
— the specific enthalpy of evaporation of water vapor at the temperature of a wet thermometer.

Ports

Input

# D — the ratio of the mass of water droplets in the tank, dimensionless value
scalar

Details

The inlet port that controls the ratio of the mass of water droplets to the mass of moist air in the tank.

Dependencies

To use this port, check the box Provide input signal for water droplets.

Data types	`Float64`
Complex numbers support	No

# Tw — the temperature of the wet thermometer in the tank, K
scalar

Details

The input port that controls the temperature of the wet thermometer in the tank.

Dependencies

To use this port, check the box Provide input signal for humidity and set for the parameter Reservoir humidity specification meaning Wet-bulb temperature.

Data types	`Float64`
Complex numbers support	No

# G — the level of impurity gases in the tank, dimensionless value
scalar

Details

The inlet port that controls the level of impurity gases in the tank. To select the value that the control signal represents, use the parameter Reservoir trace gas specification.

Dependencies

To use this port, check the box Provide input signal for trace gas.

Data types	`Float64`
Complex numbers support	No

# P — pressure in the tank, Pa
scalar

Details

The inlet port that controls the pressure in the tank.

Dependencies

To use this port, check the box Provide input signal for pressure.

Data types	`Float64`
Complex numbers support	No

# W — reservoir humidity, dimensionless value
scalar

Details

An input port that controls the humidity level in the tank. To select the value that the control signal represents, use the parameter Reservoir humidity specification.

Dependencies

To use this port, check the box Provide input signal for humidity and set for the parameter Reservoir humidity specification one of the following values:

Relative humidity;
Specific humidity;
Water vapor mole fraction;
Humidity ratio.

Data types	`Float64`
Complex numbers support	No

# T — temperature in the tank, K
scalar

Details

The input port that controls the temperature in the tank.

Dependencies

To use this port, check the box Provide input signal for temperature.

Data types	`Float64`
Complex numbers support	No

Conserving

# A — humid air port
humid air

Details

The humid air port corresponds to the entrance to the tank.

Program usage name

port

Parameters

Main

# Inputs outside valid range — actions to be taken when the signal values fall outside the acceptable range
Limit to valid values | Error

Details

Actions for the block that must be taken when the input signal values fall outside the acceptable range:

Limit to valid values — the block limits the input signal to the minimum or maximum allowed value;

Error — the simulation stops with an error.

Dependencies

To use this option, select at least one of the following check boxes:

Provide input signal for pressure;
Provide input signal for temperature;
Provide input signal for humidity;
Provide input signal for trace gas;
Provide input signal for water droplets.

Values	`Limit to valid values` \| `Error`
Default value	`Error`
Program usage name	`assert_action`
Evaluatable	No

# Reservoir temperature specification — temperature setting method
Atmospheric temperature | Specified temperature

Details

Select the temperature setting method:

Atmospheric temperature — atmospheric temperature is used.
Specified temperature — the parameter value is being used Reservoir temperature.

Values	`Atmospheric temperature` \| `Specified temperature`
Default value	`Atmospheric temperature`
Program usage name	`temperature_type`
Evaluatable	No

# Provide input signal for trace gas — the method of specifying impurity gases

Details

The method used to identify the impurity gases in the tank. If you uncheck this box, the block will simulate impurity gases based on the parameter value. Reservoir trace gas mass fraction or Reservoir trace gas mole fraction. If this option is selected, the unit will simulate impurity gases based on the value of the signal on port G.

Default value	`—`
Program usage name	`controlled_trace_gas`
Evaluatable	No

# Reservoir specific humidity — specific humidity in the tank

Details

Sets the value of the specific humidity in the tank. This value remains constant during the simulation.

Dependencies

To use this option, uncheck the box. Provide input signal for humidity and set for the parameter Reservoir humidity specification meaning Specific humidity.

Default value	`0.01`
Program usage name	`x_w_const`
Evaluatable	Yes

# Provide input signal for humidity — humidity setting method

Details

The method used to set the humidity in the tank. If you uncheck this box, the block will simulate humidity based on the parameter value. Reservoir humidity specification. If this option is selected, the unit will simulate humidity based on the value of the signal on the W or Tw port.

Default value	`—`
Program usage name	`controlled_humidity`
Evaluatable	No

# Reservoir mass ratio of water droplets to moist air — the ratio of the mass of water droplets in the tank

Details

The ratio of the mass of water droplets to the mass of moist air in the tank.

Dependencies

To use this option, uncheck the box. Provide input signal for water droplets.

Default value	`0`
Program usage name	`r_d_const`
Evaluatable	Yes

# Reservoir water vapor mole fraction — molar fraction of water vapor in the tank

Details

Enter the desired molar fraction of water vapor in the tank. This value remains constant during the simulation.

Dependencies

To use this option, uncheck the box. Provide input signal for humidity and set for the parameter Reservoir humidity specification meaning Mole fraction.

Default value	`0.01`
Program usage name	`y_w_const`
Evaluatable	Yes

# Reservoir relative humidity — relative humidity in the tank

Details

Sets the value of relative humidity in the tank. This value remains constant during the simulation.

Dependencies

To use this option, uncheck the box. Provide input signal for humidity and set for the parameter Reservoir humidity specification meaning Relative humidity.

Default value	`0.5`
Program usage name	`RH_const`
Evaluatable	Yes

Details

Enter the temperature of the wet thermometer in the tank. This value remains constant during the simulation.

Dependencies

To use this option, uncheck the box. Provide input signal for humidity and set for the parameter Reservoir humidity specification meaning Wet-bulb temperature.

Units	`K` \| `degC` \| `degF` \| `degR` \| `deltaK` \| `deltadegC` \| `deltadegF` \| `deltadegR`
Default value	`287 K`
Program usage name	`T_wb_const`
Evaluatable	Yes

# Cross-sectional area at port A — the area normal to the flow direction at the reservoir inlet
m^2 | um^2 | mm^2 | cm^2 | km^2 | in^2 | ft^2 | yd^2 | mi^2 | ha | ac

Details

The cross-sectional area of the tank inlet in the direction normal to the humid air flow path.

Units	`m^2` \| `um^2` \| `mm^2` \| `cm^2` \| `km^2` \| `in^2` \| `ft^2` \| `yd^2` \| `mi^2` \| `ha` \| `ac`
Default value	`0.01 m^2`
Program usage name	`port_area`
Evaluatable	Yes

# Reservoir humidity ratio — humidity coefficient in the tank

Details

Sets the value of relative humidity in the tank. This value remains constant during the simulation.

Dependencies

To use this option, uncheck the box. Provide input signal for humidity and set for the parameter Reservoir humidity specification meaning Humidity ratio.

Default value	`0.01`
Program usage name	`HR_const`
Evaluatable	Yes

# Provide input signal for pressure — pressure setting method

Details

The method used to set the pressure in the tank. If you uncheck this option, the unit will simulate pressure based on the parameter value. Reservoir pressure or atmospheric pressure. If this option is selected, the unit will simulate pressure based on the value of the signal on the P port.

Default value	`—`
Program usage name	`controlled_pressure`
Evaluatable	No

# Reservoir humidity specification — humidity measurement method
Relative humidity | Specific humidity | Mole fraction | Humidity ratio | Wet-bulb temperature

Details

Sets the humidity measurement method:

Relative humidity ― the humidity composition is set through the relative humidity parameter Reservoir relative humidity.
Specific humidity ― the humidity composition is set through the specific humidity parameter Reservoir specific humidity.
Water vapor mole fraction ― the humidity composition is set in terms of the molar fraction of humidity by the parameter Reservoir water vapor mole fraction.
Humidity ratio ― the humidity composition is set through the humidity coefficient parameter Reservoir humidity ratio.
Wet-bulb temperature ― the humidity composition is set through the temperature of the wet thermometer parameter Reservoir wet-bulb temperature.

Values	`Relative humidity` \| `Specific humidity` \| `Mole fraction` \| `Humidity ratio` \| `Wet-bulb temperature`
Default value	`Relative humidity`
Program usage name	`moisture_type`
Evaluatable	No

# Relative humidity at saturation — relative humidity, above which moisture condensation occurs

Details

The relative humidity above which condensation occurs. The amount of moisture should be less than the saturation level.

Default value	`1`
Program usage name	`RH_ws`
Evaluatable	Yes

# Provide input signal for temperature — the method of setting the tank temperature

Details

The method used to set the temperature in the tank. If you uncheck this box, the unit will simulate the temperature based on the parameter value. Reservoir temperature or atmospheric temperature. If this option is selected, the unit will simulate the temperature based on the value of the signal on the T port.

Default value	`—`
Program usage name	`controlled_temperature`
Evaluatable	No

# Reservoir trace gas mole fraction — molar fraction of impurity gas

Details

Enter the desired molar fraction of the impurity gas in the tank. This value remains constant during the simulation.

Dependencies

To use this option, uncheck the box. Provide input signal for trace gas and set for the parameter Reservoir trace gas specification meaning Mole fraction.

Default value	`0.001`
Program usage name	`y_g_const`
Evaluatable	Yes

# Reservoir pressure — pressure in the tank
Pa | uPa | hPa | kPa | MPa | GPa | kgf/m^2 | kgf/cm^2 | kgf/mm^2 | mbar | bar | kbar | atm | ksi | psi | mmHg | inHg

Details

Sets the pressure in the tank. This pressure remains constant throughout the simulation time.

Dependencies

To use this option, uncheck the box. Provide input signal for pressure and set for the parameter Reservoir pressure specification meaning Specified temperature.

Units	`Pa` \| `uPa` \| `hPa` \| `kPa` \| `MPa` \| `GPa` \| `kgf/m^2` \| `kgf/cm^2` \| `kgf/mm^2` \| `mbar` \| `bar` \| `kbar` \| `atm` \| `ksi` \| `psi` \| `mmHg` \| `inHg`
Default value	`0.101325 MPa`
Program usage name	`p_const`
Evaluatable	Yes

Details

Sets the temperature in the tank. This temperature remains constant throughout the simulation time.

Dependencies

To use this option, uncheck the box. Provide input signal for temperature and set for the parameter Reservoir temperature specification meaning Specified temperature.

Units	`K` \| `degC` \| `degF` \| `degR` \| `deltaK` \| `deltadegC` \| `deltadegF` \| `deltadegR`
Default value	`293.15 K`
Program usage name	`T_const`
Evaluatable	Yes

# Reservoir trace gas specification — method of measuring the amount of impurity gases
Mass fraction | Mole fraction

Details

Sets the measurement method:

Mass fraction ― the mass fraction of impurity gases is set by the parameter Reservoir trace gas mass fraction.
Mole fraction ― the molar fraction of impurity gases is set by the parameter Reservoir trace gas mole fraction.

Values	`Mass fraction` \| `Mole fraction`
Default value	`Mass fraction`
Program usage name	`trace_gas_type`
Evaluatable	No

# Reservoir pressure specification — pressure setting method
Atmospheric pressure | Specified pressure

Details

Select the pressure setting method:

Atmospheric pressure — atmospheric pressure is used.
Specified pressure — the parameter value is being used Reservoir pressure.

Dependencies

To use this option, uncheck the box. Provide input signal for pressure.

Values	`Atmospheric pressure` \| `Specified pressure`
Default value	`Atmospheric pressure`
Program usage name	`pressure_type`
Evaluatable	No

# Provide input signal for water droplets — method for setting the mass ratio of water droplets

Details

The method used to determine the mass ratio of water droplets in a tank. If you uncheck this box, the block will simulate water droplets based on the parameter value. Reservoir mass ratio of water droplets to moist air. If this option is selected, the unit will simulate water droplets based on the value of the signal on port D.

Default value	`—`
Program usage name	`controlled_droplets`
Evaluatable	No

# Reservoir trace gas mass fraction — mass fraction of impurity gas in the tank

Details

Enter the desired mass fraction of impurity gas in the tank. This value remains constant during the simulation.

Dependencies

To use this option, uncheck the box. Provide input signal for trace gas and set for the parameter Reservoir trace gas specification meaning Mass fraction.

Default value	`0.001`
Program usage name	`x_g_const`
Evaluatable	Yes

Reservoir (MA)

Description

Ports

Input

Conserving

Parameters

Main

Examples