Translational Mechanical Converter (MA)

The interface between humid air and translational mechanics networks.

blockType: AcausalFoundation.MoistAir.Elements.TranslationalMechanicalConverter

Path in the library:

/Physical Modeling/Fundamental/Moist Air/Elements/Translational Mechanical Converter (MA)

Description

Block Translational Mechanical Converter (MA) It is an interface (converter) between a humid air network and a mechanical translational network. The unit converts humid air pressure into mechanical force and vice versa. It can be used as a base for translational gas drives.

The converter contains a variable volume of humid air. The pressure and temperature vary depending on the compressibility and heat capacity of the humid air. Liquid water condenses from the volume of moist air when it reaches saturation. Parameter Mechanical orientation allows you to specify whether an increase in the volume of humid air leads to a positive or negative displacement of port R relative to port C.

Port A is the humid air port corresponding to the input of the converter. Port H is a thermal port connected to the temperature of the humid air inside the converter. Ports R and C are mechanical translational ports corresponding to the stem and body of the converter.

The equations

The block’s equations use these symbols:

Lower indexes , and They indicate the properties of dry air, water vapor, and impurity gas, respectively.;
Lower index indicates the water vapor saturation level;
Lower indexes , and specify the appropriate port;
Lower index indicates the properties of the internal volume of humid air;
— mass consumption;
— energy consumption;
— heat consumption;
— pressure;
— density;
— universal gas constant;
— the volume of moist air inside the converter;
— specific heat capacity at constant volume;
— specific enthalpy;
— specific internal energy;
— mass fraction ( — specific humidity, which is a synonym for the mass fraction of water vapor);
— molar fraction;
— relative humidity;
— humidity coefficient;
— temperature;
— the time.

Conservation of mass and energy

The net consumption of moist air in the volume of the converter is equal to:

where

— condensation consumption;
— the rate of energy loss by condensed water;
— the level of energy added by sources of moisture and impurity gases;
and — the mass consumption of water and gas, respectively, through the port S. Values , and They are determined by sources of moisture and impurity gases connected to the S port of the converter.

The conservation of water vapor mass relates the mass flow of water vapor to the dynamics of the humidity level in the internal volume of humid air:

Similarly, the conservation of impurity gas mass relates the mass flow rate of impurity gas to the dynamics of the impurity gas level in the internal volume of humid air.:

The conservation of the mass of the mixture relates the mass flow rate of the mixture to the dynamics of pressure, temperature, and mass fractions of the internal volume of moist air.:

where — volumetric flow rate of the converter.

Finally, energy conservation relates energy consumption to the dynamics of pressure, temperature, and mass fractions of the internal volume of humid air.:

The equation of state relates the density of a mixture to pressure and temperature:

The universal gas constant of the mixture is:

Converter volume:

where

— the volume of liquid at which the position of the stem is equal to 0;
— the cross-sectional area of the rod;
— displacement of the stem;
— coefficient of mechanical orientation. If the parameter value is Mechanical orientation Pressure at A causes positive displacement of R relative to C Then . If Pressure at A causes negative displacement of R relative to C Then .

The position of the rod is zero if the volume of moist air inside the transducer is . Then, depending on the value of the parameter Mechanical orientation, the following is true:

If the pressure at point A causes a positive displacement of R relative to C, then the displacement of the rod increases when the volume of humid air increases compared to .
If the pressure at point A causes a negative displacement of R relative to C, then the displacement of the rod decreases when the volume of moist air increases compared to .

The balance of forces on the mechanical interface is:

where

— the power transmitted from port R to port C;
— ambient pressure.

The gas and thermal resistances in the converter are not modeled:

When the volume of humid air reaches saturation, condensation of moisture may occur. The specific humidity at saturation is:

where

— relative humidity at saturation (usually 1);
— water vapor saturation pressure corresponding to the temperature .

The condensation rate is:

where — parameter value Condensation time constant.

Condensed water is subtracted from the volume of moist air, as shown in the conservation equations. The energy associated with condensed water is:

where — specific enthalpy of evaporation, estimated at .

The amounts of moisture and impurity gases are related to each other as follows:

Assumptions and limitations

The converter housing is absolutely rigid.
The gas resistance between the input of the transducer and the volume of humid air is not modeled. Connect the block Variable Local Restriction (MA) or a block Flow Resistance (MA) to port A to simulate the pressure loss associated with the inlet.
The thermal resistance between the H port and the volume of humid air is not modeled. Use the thermal library blocks to simulate the thermal resistance between the moist air mixture and the environment, including any thermal effects of the chamber walls.
The movable rod operates losslessly.
The block does not simulate mechanical effects such as mechanical constraints, friction, and inertia.

Variables

Use the parameter group Initial Targets to set the priority and initial target values for the block parameter variables before modeling. For more information, see Configuring physical blocks using target values.

Ports

Conserving

# C — hull
translational mechanics

Details

Mechanical progressive port, corresponds to the inverter housing.

Program usage name

case_flange

# R — stem
translational mechanics

Details

Mechanical progressive port, corresponds to the rod.

Program usage name

rod_flange

# H — internal temperature
`heat

Details

Heat port, related to the temperature of the humid air inside the inverter.

Program usage name

thermal_port

# S — addition or removal of moisture and impurity gases
`moist air

Details

Connect this port to the S port of the unit from the library Moist Air: Sources to add or remove moisture and impurity gases.

Program usage name

source_port

# A — humid air inlet
humid air

Details

Humid air port, corresponds to the inverter input.

Program usage name

port

Input

# interface_displacement_in — description missing

Details

Description missing

Data types	Description missing
Complex numbers support	Description missing

Output

# mdot_w_out — description missing

Details

Description missing

Data types	Description missing
Complex numbers support	Description missing

# F — information on pressure, temperature, humidity and amount of impurity gases
`vector'

Details

Output port of the signal; a vector with the following elements: pressure, temperature, humidity level and the amount of impurity gases inside the component. The Measurement Selector (MA) block is used to decompress the vector signal.

Data types	`Float64`.
Complex numbers support	No

Parameters

Initial Conditions

# Initial trace gas mass fraction — description missing

Details

description missing

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

# Initial relative humidity — description missing

Details

description missing

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

Details

description missing

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

# Initial specific humidity — description missing

Details

description missing

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

Details

description missing

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

# Initial humidity ratio priority — description missing
None | Low | High

Details

description missing

Values	`None` \| `Low` \| `High`
Default value	`High`
Program usage name	`HR_priority`
Evaluatable	No

# Initial water vapor mole fraction — description missing

Details

description missing

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

# Initial temperature priority — description missing
None | Low | High

Details

description missing

Values	`None` \| `Low` \| `High`
Default value	`High`
Program usage name	`T_priority`
Evaluatable	No

# Initial humidity ratio — description missing

Details

description missing

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

# Initial trace gas mole fraction — description missing

Details

description missing

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

# Initial specific humidity priority — description missing
None | Low | High

Details

description missing

Values	`None` \| `Low` \| `High`
Default value	`High`
Program usage name	`x_w_priority`
Evaluatable	No

# Initial mass ratio of water droplets to moist air — description missing

Details

description missing

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

# Initial trace gas specification — description missing
Mass fraction | Mole fraction

Details

description missing

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

# Initial pressure priority — description missing
None | Low | High

Details

description missing

Values	`None` \| `Low` \| `High`
Default value	`High`
Program usage name	`p_priority`
Evaluatable	No

# Initial mass ratio of water droplets to moist air priority — description missing
None | Low | High

Details

description missing

Values	`None` \| `Low` \| `High`
Default value	`High`
Program usage name	`r_d_priority`
Evaluatable	No

# Initial trace gas mole fraction priority — description missing
None | Low | High

Details

description missing

Values	`None` \| `Low` \| `High`
Default value	`High`
Program usage name	`y_g_priority`
Evaluatable	No

# Initial wet-bulb temperature priority — description missing
None | Low | High

Details

description missing

Values	`None` \| `Low` \| `High`
Default value	`High`
Program usage name	`T_wb_priority`
Evaluatable	No

# Initial trace gas mass fraction priority — description missing
None | Low | High

Details

description missing

Values	`None` \| `Low` \| `High`
Default value	`High`
Program usage name	`x_g_priority`
Evaluatable	No

# Initial water vapor mole fraction priority — description missing
None | Low | High

Details

description missing

Values	`None` \| `Low` \| `High`
Default value	`High`
Program usage name	`y_w_priority`
Evaluatable	No

# Initial relative humidity priority — description missing
None | Low | High

Details

description missing

Values	`None` \| `Low` \| `High`
Default value	`High`
Program usage name	`RH_priority`
Evaluatable	No

# Initial pressure — description missing
Pa | uPa | hPa | kPa | MPa | GPa | kgf/m^2 | kgf/cm^2 | kgf/mm^2 | mbar | bar | kbar | atm | ksi | psi | mmHg | inHg

Details

description missing

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_start`
Evaluatable	Yes

# Initial humidity specification — description missing
Relative humidity | Specific humidity | Mole fraction | Humidity ratio | Wet-bulb temperature

Details

description missing

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

Moisture and Trace Gas

# Added trace gas temperature specification — method for setting the impurity gas temperature
Atmospheric temperature | Specified temperature

Details

Selection of the impurity gas temperature setting method:

Atmospheric temperature - atmospheric temperature is used.
Specified temperature - value is set with the parameters Temperature of added trace gas.

Dependencies

To use this parameter, set the Moisture and trace gas source parameters to . Constant.

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

Details

description missing

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

# Relative humidity at saturation — description missing

Details

description missing

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

# Fraction of condensate entrained as water droplets — description missing

Details

description missing

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

Details

description missing

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

Details

description missing

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

# Condensation time constant — condensation time constant
s | ns | us | ms | min | hr | d

Details

A time scale factor characterising the time period for the return of the supersaturated volume of moist air to the saturation level due to condensation of excess moisture.

Units	`s` \| `ns` \| `us` \| `ms` \| `min` \| `hr` \| `d`
Default value	`0.001 s`
Program usage name	`condensation_time_constant`
Evaluatable	Yes

Details

description missing

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_g_const`
Evaluatable	Yes

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

Details

Select whether the unit adds or removes moisture as water vapour or water:

Vapor - the enthalpy of added or removed moisture corresponds to the enthalpy of water vapour, which is greater than the enthalpy of water.
Liquid - the enthalpy of added or removed moisture corresponds to the enthalpy of water, which is less than the enthalpy of water vapour.

Dependencies

To use this parameter, set the parameter Moisture and trace gas source to . Constant.

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

# Added moisture temperature specification — Moisture temperature setting method
Atmospheric temperature | Specified temperature

Details

Selects the method for setting the moisture temperature:

Atmospheric temperature - atmospheric temperature is used.
Specified temperature - value is set with the parameters Temperature of added moisture.

Dependencies

To use this parameter, set the Moisture and trace gas source parameters to . Constant.

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

# Water droplets evaporation time constant — description missing
s | ns | us | ms | min | hr | d

Details

description missing

Units	`s` \| `ns` \| `us` \| `ms` \| `min` \| `hr` \| `d`
Default value	`0.001 s`
Program usage name	`evaporation_time_constant`
Evaluatable	Yes

# Moisture and trace gas source — source of moisture and impurity gases
None | Constant | Controlled

Details

This parameter controls the usage of the S port and provides the following options for modelling moisture and impurity gas levels within the unit:

None - no moisture or impurity gas is introduced into or extracted from the block. The S port is hidden. This value is used by default.
Constant - moisture and impurity gas are fed into or extracted from the unit at a constant flow rate. The same parameters as in the Moisture Source (MA) and Trace Gas Source (MA) units are made available in the unit settings. The S port is hidden.
Controlled - Moisture and impurity gas are introduced into or removed from the unit at a time-varying flow rate. Port S is available. Units Moisture Source (MA) and Trace Gas Source (MA) are connected to this port.

Values	`None` \| `Constant` \| `Controlled`
Default value	`None`
Program usage name	`moisture_trace_gas_source`
Evaluatable	No

# Water vapor evaporated from liquid or condensed to liquid — description missing

Details

description missing

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

Main

# Initial interface displacement — description missing
m | um | mm | cm | km | in | ft | yd | mi | nmi

Details

description missing

Units	`m` \| `um` \| `mm` \| `cm` \| `km` \| `in` \| `ft` \| `yd` \| `mi` \| `nmi`
Default value	`0 m`
Program usage name	`interface_displacement_start`
Evaluatable	Yes

# Dead volume — Humid air volume at zero stem displacement
m^3 | um^3 | mm^3 | cm^3 | km^3 | ml | l | gal | igal | in^3 | ft^3 | yd^3 | mi^3

Details

Volume of humid air at stem displacement equal to 0.

Units	`m^3` \| `um^3` \| `mm^3` \| `cm^3` \| `km^3` \| `ml` \| `l` \| `gal` \| `igal` \| `in^3` \| `ft^3` \| `yd^3` \| `mi^3`
Default value	`1.0e-5 m^3`
Program usage name	`dead_volume`
Evaluatable	Yes

# Environment pressure specification — description missing
Atmospheric pressure | Specified pressure

Details

description missing

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

# Environment pressure — description missing
Pa | uPa | hPa | kPa | MPa | GPa | kgf/m^2 | kgf/cm^2 | kgf/mm^2 | mbar | bar | kbar | atm | ksi | psi | mmHg | inHg

Details

description missing

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_environment`
Evaluatable	Yes

# Cross-sectional area at port A — area normal to the flow cross-section at the inlet to the transducer
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 transmitter inlet in the direction normal to the wet 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

# Interface cross-sectional area — area pressurised by moist air
m^2 | um^2 | mm^2 | cm^2 | km^2 | in^2 | ft^2 | yd^2 | mi^2 | ha | ac

Details

The area pressurised by moist air to produce a translational force.

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	`piston_area`
Evaluatable	Yes

# Mechanical orientation — converter orientation
Pressure at A causes positive displacement of R relative to C | Pressure at A causes negative displacement of R relative to C

Details

Sets the orientation of the movement of the mechanical part in relation to the change in the volume of moist air:

Pressure at A causes positive displacement of R relative to C - an increase in the humid air volume results in a positive displacement of the R port relative to the C port.
Pressure at A causes negative displacement of R relative to C - an increase in the volume of humid air results in a negative displacement of port R relative to port C.

Values	`Pressure at A causes positive displacement of R relative to C` \| `Pressure at A causes negative displacement of R relative to C`
Default value	`Pressure at A causes positive displacement of R relative to C`
Program usage name	`orientation`
Evaluatable	No

Translational Mechanical Converter (MA)

Description

The equations

Conservation of mass and energy

Assumptions and limitations

Variables

Ports

Conserving

Input

Output

Parameters

Initial Conditions

Moisture and Trace Gas

Main

Examples