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Trace Gas Source (MA)

Inject or extract trace gas at a constant or time-varying rate

  • Trace Gas Source (MA) block

Libraries:
Simscape / Foundation Library / Moist Air / Sources / Moisture & Trace Gas Sources

Description

The Trace Gas Source (MA) block represents a constant or time-varying source or sink of trace gas for the connected moist air volume. A positive or negative trace gas mass flow rate causes trace gas levels to increase or decrease, respectively.

For a time-varying source, two physical signal input ports, M and T, supply the mass flow rate and temperature values, respectively. Alternatively, you can specify constant mass flow rate and temperature as block parameters.

The energy associated with the added or removed trace gas is

Φs={m˙specifiedhg(Tspecified),if m˙specified0m˙specifiedhg(Ts),if m˙specified<0 

where:

  • m˙specified is the trace gas mass flow rate specified by the input physical signal at port M or by the Trace gas mass flow rate parameter.

  • hg is the trace gas specific enthalpy.

  • Tspecified is the temperature of added trace gas, as specified by the input physical signal at port T or by the block parameters. The block uses this value to evaluate the specific enthalpy of the added trace gas only. The specific enthalpy of removed trace gas is based on the temperature of the connected moist air volume.

  • Ts is the temperature at port S, which is the same as the temperature of the connected moist air volume.

Port S is a moist air source conserving port. Connect this port to port S of a block with finite moist air volume to add or remove trace gas through that block. For more information, see Using Moisture and Trace Gas Sources.

Examples

Ports

Input

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Input physical signal that specifies the trace gas mass flow rate through the source.

Dependencies

To enable this port, set the Source type parameter to Controlled.

Input physical signal that specifies the temperature of added trace gas. The block uses this value to evaluate the specific enthalpy of the added trace gas only. The specific enthalpy of removed trace gas is based on the temperature of the connected moist air volume.

Dependencies

To enable this port, set the Source type parameter to Controlled.

Conserving

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Connect this port to port S of a block with finite moist air volume to add or remove trace gas through that block.

Parameters

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Select whether the trace gas mass flow rate and temperature can change during simulation:

  • Controlled — The trace gas mass flow rate and temperature are variable, controlled by input physical signals. Selecting this option exposes the input ports M and T.

  • Constant — The trace gas mass flow rate and temperature are constant during simulation, specified by block parameters. Selecting this option enables these parameters.

Trace gas mass flow rate through the source. A positive value adds trace gas to the connected moist air volume. A negative value extracts trace gas from that volume.

Dependencies

To enable this parameter, set Source type to Constant.

Select a specification method for the trace gas temperature:

  • Atmospheric temperature — Use the atmospheric temperature, specified by the Moist Air Properties (MA) block connected to the circuit.

  • Specified temperature — Specify a value by using the Temperature of added trace gas parameter.

Dependencies

To enable this parameter, set Source type to Constant.

Enter the desired temperature of added trace gas. This temperature remains constant during simulation. The block uses this value to evaluate the specific enthalpy of the added trace gas only. The specific enthalpy of removed trace gas is based on the temperature of the connected moist air volume.

Dependencies

To enable this parameter, set Added trace gas temperature specification to Specified temperature.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced in R2018a

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