Interface (TL-IL)

Connection between thermal and isothermal networks

Since R2020a

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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.

You can connect Thermal Liquid library blocks with Isothermal Liquid library or Hydraulics (Isothermal) library blocks. 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.

Thermal Liquid - Isothermal Liquid

When Fluids domain interface is set to Thermal Liquid (TL) - Isothermal Liquid (IL), the mass flow rate is conserved over the two mass-flow-rate-based 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:

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

Thermal Liquid - Hydraulics (Isothermal)

The Hydraulics (Isothermal) Liquid library is based on volumetric flow rate. To maintain flow continuity between both sides of the interface, the volumetric flow rate is multiplied by the fluid density:

$${\dot{m}}_{TL}+q_H{\rho }_H=0,$$

where:

• q_H is the Hydraulics (Isothermal) volumetric flow rate.

• ρ_H is the local Hydraulics (Isothermal) fluid density.

The Hydraulics (Isothermal) Liquid library blocks are constructed in terms of gauge pressures. Pressure is converted to absolute pressure internally to match the thermal network pressure:

$$p_H+p_{atm}=p_{TL}.$$

Ports

Conserving

TL — Liquid port

thermal liquid

Entry or exit port to the thermal liquid network.

IL — Liquid port

isothermal liquid

Entry or exit port to the isothermal liquid network.

Dependencies

To enable this port, set Fluids domain interface to Thermal Liquid (TL) - Isothermal Liquid (IL).

H — Liquid port

isothermal liquid

Entry or exit port to the hydraulics (isothermal) liquid network.

Dependencies

To enable this port, set Fluids domain interface to Thermal Liquid (TL) - Hydraulic (H).

Parameters

Fluids domain interface — Connecting library types

Thermal Liquid (TL) - Isothermal Liquid (IL) (default) | Thermal Liquid (TL) - Hydraulic (H)

Specifies the connecting library types.

Temperature specification — Isothermal network temperature

Constant (default) | Controlled

Sets the isothermal network temperature. In the Constant setting, you can specify the isothermal network temperature in the Hydraulic temperature parameter. In the Controlled setting, the temperature in the isothermal network is set by the thermal network.

Interface temperature — Isothermal network temperature

293.15 K (default) | positive scalar

Specifies the fluid temperature transmitted from the thermal liquid network to the hydraulic or isothermal liquid network.

Dependencies

To enable this parameter, set Temperature specification to Constant.

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.

Extended Capabilities

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

Version History

Introduced in R2020a