Controlled Trace Gas Source (MA)

Inject or extract trace gas at a time-varying rate

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

Description

The Controlled Trace Gas Source (MA) block represents a time-varying source or sink of trace gas for the connected moist air volume. Two physical signal input ports, M and T, supply the mass flow rate and temperature values, respectively. A positive or negative trace gas mass flow rate causes trace gas levels to increase or decrease, respectively.

The energy associated with the added or removed trace gas is

$${\Phi }_s=\{\begin{array}{ll}{\dot{m}}_{specified}\cdot h_g\left(T_{specified}\right),\hfill & \text{if }{\dot{m}}_{specified}\ge 0\hfill \\ {\dot{m}}_{specified}\cdot h_g\left(T_s\right),\hfill & \text{if }{\dot{m}}_{specified}<0\hfill \end{array}$$

where:

• $${\dot{m}}_{specified}$$ is the trace gas mass flow rate specified by the input physical signal at port M.

• h_g is the trace gas specific enthalpy.

• T_specified is the temperature of added trace gas specified by the input physical signal at port T. 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.

• T_s 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

Aircraft Environmental Control System

Models an aircraft environmental control system (ECS) that regulates pressure, temperature, humidity, and ozone (O3) to maintain a comfortable and safe cabin environment. Cooling and dehumidification are provided by the air cycle machine (ACM), which operates as an inverse Brayton cycle to remove heat from pressurized hot engine bleed air. Some hot bleed air is mixed directly with the output of the ACM to adjust the temperature. Pressurization is maintained by the outflow valve in the cabin. This model simulates the ECS operating from a hot ground condition to a cold cruise condition and back to a cold ground condition.

Open Model

Ports

Input

M — Mass flow rate control signal, kg/s

physical signal

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

T — Temperature of added trace gas, K

physical signal

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.

Conserving

S — Inject or extract trace gas

moist air source

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

Extended Capabilities

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

Version History

Introduced in R2018a