Moisture Source (MA)

Adding or removing moisture with constant or variable flow rate.

blockType: AcausalFoundation.MoistAir.MoistureTraceGasSources.Moisture

Controlled Moisture Source (MA)

Path in the library:

/Physical Modeling/Fundamental/Moist Air/Moisture & Trace Gas Sources/Controlled Moisture Source (MA)

Moisture Source (MA)

Path in the library:

/Physical Modeling/Fundamental/Moist Air/Moisture & Trace Gas Sources/Moisture Source (MA)

Description

Block Moisture Source (MA) It is a constant or time-varying source or absorber of moisture or droplets for a connected volume with moist air.

A positive or negative mass consumption of moisture leads to an increase or decrease in its level, respectively.

Moisture can be added in the form of steam or water.

When for the parameter Moisture added or removed the value is set Water vapor, parameter Water vapor evaporated from liquid or condensed to liquid controls the way steam exits or enters the block. When unchecking the box Water vapor evaporated from liquid or condensed to liquid The unit removes water vapor from a volume of liquid at a preset rate. When the checkbox is selected Water vapor evaporated from liquid or condensed to liquid The block assumes that steam entering the volume of liquid is formed from evaporated water, and steam leaving the volume condenses into liquid. In this case, the unit also simulates changes in latent heat from each of these processes.

If the check box Water vapor evaporated from liquid or condensed to liquid removed, the energy associated with adding or removing moisture is:

where

— the mass flow rate of water vapor, set by the input scalar signal on the port M or the parameter Rate of moisture added;
— specific enthalpy of water vapor;
— the temperature of the added water vapor, set by the input scalar signal on the port T or the parameter Temperature of added moisture. The unit uses this value to estimate the specific enthalpy of the added moisture alone. The specific enthalpy of the removed moisture is determined by the temperature of the connected volume with moist air;
— this is the temperature on the S port, which is equal to the temperature of the connected volume with humid air.

If the check box Water vapor evaporated from liquid or condensed to liquid It is established that the energy associated with the addition or removal of moisture is equal to:

where — specific enthalpy of evaporation of water.

Ports

Input

# M — mass flow rate, kg/s
scalar

Details

An input port that determines the mass flow of moisture through the source.

Dependencies

To use this port, check the box Controlled source.

Data types	`Float64`
Complex numbers support	I don’t

# T — temperature, K
scalar

Details

The input port that determines the temperature of the added moisture. The unit uses this value to estimate the specific enthalpy of the added moisture alone. The specific enthalpy of the removed moisture is determined by the temperature of the connected volume with moist air.

Dependencies

To use this port, check the box Controlled source.

Data types	`Float64`
Complex numbers support	I don’t

Conserving

# S — adding or removing moisture
humid air

Details

Humid air source port. Connect this port to the S port of the unit with a finite volume of humid air to add or remove moisture with the unit Controlled Moisture Source (MA).

Program usage name

source_port

Parameters

Main

Details

The temperature of the moisture. This temperature remains constant during the simulation. The unit uses this value only to estimate the specific enthalpy of added moisture. The specific enthalpy of the removed moisture is determined based on the temperature of the connected volume with moist air.

Dependencies

To use this option, uncheck the box. Controlled source and set for the parameter Added moisture temperature specification meaning Specified temperature.

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

# Added moisture temperature specification — method for setting the moisture temperature
Atmospheric temperature | Specified temperature

Details

Choosing a method for setting the moisture temperature:

Atmospheric temperature — the atmospheric temperature set by the unit is used Moist Air Properties (MA), connected to the network.
Specified temperature — the value is set using the parameter Temperature of added moisture.

Dependencies

To use this option, uncheck the box. Controlled source.

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

# Water vapor evaporated from liquid or condensed to liquid — add or remove water vapor

Details

Select the method of adding or removing water vapor by the unit:

If unchecked, the enthalpy of added or removed moisture corresponds to the enthalpy of water vapor, which is greater than the enthalpy of water.
If this option is selected, the enthalpy of added or removed moisture corresponds to the enthalpy of water, which is less than the enthalpy of water vapor.

When water vapor is added, it evaporates from the liquid, and the latent heat is released by the bound volume of the liquid. When water vapor is removed, it condenses into a liquid, and latent heat is released to the associated volume of liquid.

Dependencies

To use this parameter, set for the parameter Moisture added or removed meaning Water vapor.

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

Details

The mass flow of moisture through the source.

A positive value adds moisture to the connected volume with moist air. A negative value removes moisture from this volume.

Dependencies

To use this option, uncheck the box. Controlled source.

Units	`kg/s` \| `kg/hr` \| `kg/min` \| `g/hr` \| `g/min` \| `g/s` \| `t/hr` \| `lbm/hr` \| `lbm/min` \| `lbm/s`
Default value	`0 kg/s`
Program usage name	`mdot_moisture_const`
Evaluatable	Yes

# Controlled source — is the flow rate and temperature of moisture set by the input signal

Details

Determines how the moisture flow rate and temperature will be set:

If this option is selected, the moisture flow rate and temperature are set via the input ports M and T.
If the box is not checked, then the constant flow rate and temperature of moisture are set using the parameters Rate of moisture added and Added moisture temperature specification accordingly.

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

# Moisture added or removed — add or remove moisture in the form of steam or water
Water vapor | Water droplets

Details

Choose the form in which the source adds or removes moisture.: in the form of steam or water:

Water vapor — the enthalpy of added or removed moisture corresponds to the enthalpy of water vapor, which is greater than the enthalpy of water.
Water droplets — the enthalpy of added or removed moisture corresponds to the enthalpy of water, which is less than the enthalpy of water vapor.

Values	`Water vapor` \| `Water droplets`
Default value	`Water vapor`
Program usage name	`moisture_source_phase`
Evaluatable	No

Examples

Simulation of an artificial lung ventilation system