Reservoir (TL)

Boundary conditions for thermal liquid network at constant or time-varying pressure and temperature

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Libraries:
Simscape / Foundation Library / Thermal Liquid / Elements

Description

The Reservoir (TL) block sets boundary conditions in a thermal liquid network. The volume of liquid inside the reservoir is assumed infinite. Port A, a thermal liquid conserving port, represents the reservoir inlet.

The inlet temperature depends on the direction of liquid flow. If liquid flows into the reservoir, the inlet temperature equals that of the upstream liquid and the reservoir acts as a heat sink. If liquid flows out of the reservoir, the inlet temperature equals that of the reservoir and the reservoir acts as a heat source. You specify the reservoir pressure and temperature with block parameter values or physical signals.

To ensure a smooth temperature change at the reservoir inlet during liquid flow reversal, the block includes heat conduction along a length equal to the effective diameter of the inlet pipe. This diameter is a function of the specified cross-sectional area of the inlet pipe.

Examples

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

Input

P — Pressure control signal, Pa

physical signal

Physical signal port that provides the reservoir pressure control signal.

Dependencies

To enable this port, select Provide input signal for pressure.

T — Temperature control signal, K

physical signal

Physical signal port that provides the reservoir temperature control signal.

Dependencies

To enable this port, select Provide input signal for temperature.

Conserving

A — Reservoir inlet

thermal liquid

Thermal liquid conserving port associated with the reservoir inlet.

Parameters

Provide input signal for pressure — Method to specify pressure

off (default) | on

Method to use to specify the pressure in the reservoir. If you clear this check box, the block models pressure based on the value of the Reservoir pressure parameter or atmospheric pressure. If you select this check box, the block models pressure based on the value of the signal at port P.

Reservoir pressure specification — Specification method for constant reservoir pressure

Atmospheric pressure (default) | Specified pressure

Specification method for the reservoir pressure:

• Atmospheric pressure — Use the atmospheric pressure specified by a Thermal Liquid Settings (TL) or Thermal Liquid Properties (TL) block connected to the circuit.

• Specified pressure — Specify a value by using the Reservoir pressure parameter.

Dependencies

To enable this parameter, clear the Provide input signal for pressure check box.

Reservoir pressure — Pressure in reservoir

0.101325 MPa (default)

Desired pressure in the reservoir. This pressure remains constant during simulation.

Dependencies

To enable this parameter, clear the Provide input signal for pressure check box and set Reservoir pressure specification to Specified pressure.

Provide input signal for temperature — Method to specify reservoir temperature

off (default) | on

Method to use to specify the temperature in the reservoir. If you clear this check box, the block models temperature based on the value of the Reservoir temperature parameter. If you select this check box, the block models temperature based on the value of the signal at port T.

Reservoir temperature — Temperature in reservoir

293.15 K (default)

Desired temperature in the reservoir. This temperature remains constant during simulation.

Dependencies

To enable this parameter, clear the Provide input signal for temperature check box.

Cross-sectional area at port A — Area normal to flow path at reservoir inlet

0.01 m^2 (default)

Cross-sectional area of the reservoir inlet pipe. The block uses this area to determine the characteristic length of the pipe along which heat conduction occurs.

Inputs outside valid range — Action to take when signal values are outside of valid range

Warn and limit to valid values (default) | Limit to valid values | Error

Action for the block to take when the input signal values are outside of valid range:

• Limit to valid values ― The block limits the input signal to the minimum or maximum valid values, but does not issue a warning.

• Warn and limit to valid values ― The block issues a warning and limits the input signal to the minimum or maximum valid values.

• Error ― Simulation stops with an error.

Dependencies

To enable this parameter, select at least one of these check boxes:

• Provide input signal for pressure

• Provide input signal for temperature

Extended Capabilities

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

Version History

Introduced in R2015a

R2026a: Model a controlled reservoir

The Controlled Reservoir (TL) and Reservoir (TL) blocks have been combined into the Reservoir (TL) block. Select the Provide input signal for pressure and Provide input signal for temperature check boxes to control the reservoir conditions by using input signals. Otherwise, you can control the reservoir conditions by using the block parameters.

If you use a Controlled Reservoir (TL) block in your custom composite components, you must update the composite component code:

• Old syntax: source = foundation.thermal_liquid.elements.controlled_reservoir;

• New syntax: source = foundation.thermal_liquid.elements.reservoir;