Absolute Reference (TL)

R2026b

(Not recommended) Reference point at zero absolute temperature and pressure

Using this block is no longer recommended. Instead, make absolute measurements by setting the Measurement reference parameter of the Pressure & Temperature Sensor (TL) block to Absolute. (since R2023a)

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Absolute Reference (TL) 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 / Foundation Library / Thermal Liquid / Elements

Description

The Absolute Reference (TL) block represents an absolute reference for the pressure and temperature in thermal liquid systems. At port A, the pressure and temperature are both equal to zero.

Examples

Hydraulic Fluid Warming Due to Losses

Model shows how Foundation Library thermal liquid components can be used to estimate the impact of viscous losses on an actuating system's temperature over a long time scale. A pump supplies energy to the system to actuate a double-acting cylinder periodically. The pressure losses within directional valve converts the energy into heat. Heat transfer through the cylinder casing to the environment provides a heat sink.

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Optimal Pipeline Geometry for Heated Oil Transportation

Model shows the opposing effects of viscous warming and conductive cooling on the temperature of a buried pipeline segment for heated oil transportation. A requirement for these systems is for the crude oil to stay well above the pour point to provide a continuous steady flow. The system is modeled using the Thermal Liquid Foundation Library. Crude oil thermodynamic properties are stored in workspace matrices and are used to populate the Thermal Liquid Settings block mask parameters.

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Water Hammer Effect

Model shows how the Thermal Liquid foundation library can be used to model water hammer in a long pipe. After slowly establishing a steady flow within the pipe by opening a valve accordingly, the same valve is shut within a few milliseconds. This triggers a water hammer effect. The valve is modeled using a Variable Local Restriction (TL) block and the pipe is divided into four segments using the Pipe (TL) block. Breaking the pipe into more segments increases fidelity at the expense of simulation performance.

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Ports

Conserving

A — Pressure and temperature are zero

thermal liquid

Thermal liquid conserving port where the pressure and temperature are both equal to zero.

Programmatic Use

Port: A

Programmatic Use: Add Block

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

"fl_lib/Thermal Liquid/Elements/Absolute Reference (TL)"

Example: add_block("fl_lib/Thermal Liquid/Elements/Absolute Reference (TL)","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 R2013b

R2023a: Absolute Reference (TL) block no longer recommended

The Pressure & Temperature Sensor (TL) block now contains an implicit reference node, which means that you need only one port to make absolute measurements of pressure or temperature. Expose the second port only if you need to measure the difference in pressure or temperature between two nodes in the model.

In previous releases, to measure the absolute pressure and absolute temperature at port A, you needed to connect port B to an Absolute Reference (TL) block. This is no longer necessary because you can now make absolute measurements by setting the Measurement reference parameter of the Pressure & Temperature Sensor (TL) block to Absolute.

This change has no compatibility impact. Existing models that have an Absolute Reference (TL) block connected to a Pressure & Temperature Sensor (TL) block continue to work as before.