Interface (TL-IL)

R2026b

Connection between thermal and isothermal networks

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Interface (TL-IL) block

To add a block to a model, double-click the canvas and start typing the block name. Then, select the block from the list.

Libraries:
Simscape / Fluids / Fluid Network Interfaces

Description

The Interface block is a connector between thermal and isothermal fluid networks. The fluid mass flow rate and pressure are matched between the networks, but fluid properties are not passed between the two networks. To maintain fluid properties between the thermal and isothermal components of your model, connect an Isothermal Liquid Predefined Properties (IL) block with the desired properties to the isothermal network side.

The temperature set in the isothermal system can either be Constant or Controlled. In the case of a Controlled temperature system, the isothermal network temperature is set by the thermal liquid temperature. In the Constant temperature setting, you specify the isothermal network temperature directly.

The mass flow rate is conserved over the two networks

$${\dot{m}}_{TL}+{\dot{m}}_{IL}=0,$$

where:

• $$\dot{m}$$_TL is the mass flow rate at the thermal liquid interface.

• $$\dot{m}$$_IL is the mass flow rate at the isothermal liquid interface.

The fluid absolute pressure is maintained between the thermal, internal, and isothermal sections of the Interface block:

$$p_{TL}=p_{IL}.$$

Ports

Conserving

TL — Liquid port

thermal liquid

Entry or exit port to the thermal liquid network.

Programmatic Use

Port: TL

IL — Liquid port

isothermal liquid

Entry or exit port to the isothermal liquid network.

Programmatic Use

Port: IL

Parameters

Temperature specification — Isothermal network temperature

Constant (default) | Controlled

Sets the isothermal network temperature. In the Constant setting, specify the isothermal network temperature with the Interface temperature parameter. In the Controlled setting, the temperature in the isothermal network is set by the thermal network.

Programmatic Use

Parameter:	temperature_spec
Values:	"foundation.enum.constant_controlled.constant" | "foundation.enum.constant_controlled.controlled"

Interface temperature — Isothermal network temperature

293.15 K (default) | positive scalar

Fluid temperature transmitted from the thermal liquid network to the isothermal liquid network.

Dependencies

To enable this parameter, set Temperature specification to Constant.

Programmatic Use

Parameter: T_interface

Cross-sectional area at port TL — Thermal liquid port area

0.01 m^2 (default) | positive scalar

Cross-sectional area of the thermal liquid port.

Programmatic Use

Parameter: area_TL

Programmatic Use: Add Block

To add the block programmatically, use the add_block function with one of these library block paths as the source.

"SimscapeFluids_lib/Fluid Network Interfaces/Interface (TL-IL)"

Example: add_block("SimscapeFluids_lib/Fluid Network Interfaces/Interface (TL-IL)","myModel/myBlock",MakeNameUnique="on")

For information about programmatic access to individual block parameters, see the Programmatic Use section of parameter descriptions on this page.

Extended Capabilities

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

Version History

Introduced in R2020a

R2026b: Support for hydraulic (isothermal) domain removed

You can no longer connect the Interface (TL-IL) block to blocks from the hydraulic (isothermal) domain. The Hydraulics (Isothermal) library has been removed. Use the Isothermal Liquid library instead.