Cap (G)

Gas port terminator with zero flow

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Libraries:
Simscape / Foundation Library / Gas / Elements

Description

The Cap (G) block represents a perfectly insulated terminus for a gas network branch. There is no mass or energy flow through the cap.

You can use this block to terminate gas ports on other blocks that you want to cap. This is not necessary because if you leave a conserving port unconnected, the physical network sets all the Through variables at that port to 0. However, terminator blocks improve diagram readability.

You can also use this block to set the initial pressure and temperature at a node.

Variables

To set the priority and initial target values for the block variables prior to simulation, use the Initial Targets section in the block dialog box or Property Inspector. For more information, see Set Priority and Initial Target for Block Variables and Initial Conditions for Blocks with Finite Gas Volume.

Nominal values provide a way to specify the expected magnitude of a variable in a model. Using system scaling based on nominal values increases the simulation robustness. Nominal values can come from different sources, one of which is the Nominal Values section in the block dialog box or Property Inspector. For more information, see Modify Nominal Values for a Block Variable.

Examples

Building Ventilation

Models a ventilation circuit in a building. The air volume inside the building is divided into four zones. The ventilation unit blows cool air into Zone 1 and extracts air from Zone 3. The extracted air can be optionally recycled back into Zone 1. A door in Zone 4 can be opened to vent air out to the atmosphere.

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Ports

Conserving

A — Mass flow rate and energy flow rate are zero

gas

Gas conserving port where the mass flow rate and energy flow rate are both equal to zero.

Extended Capabilities

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

Version History

Introduced in R2016b

R2019b: Capping unconnected ports is no longer required

This block is no longer required. Starting in R2019b, the restriction that disallowed unconnected conserving ports in Simscape™ models has been lifted. Now, if you leave a conserving port unconnected, the physical network sets all the Through variables at this port to 0. However, you can still use terminator blocks to improve diagram readability.

There are no plans to remove the terminator blocks. All existing models that use these blocks work the same as in previous releases.