Main Content

Isothermal Liquid Predefined Properties (IL)

Set working fluid properties for an isothermal liquid network

Since R2020a

expand all in page
  • Isothermal Liquid Predefined Properties (IL) block

Libraries:
Simscape / Fluids / Isothermal Liquid / Utilities

Description

The Isothermal Liquid Predefined Properties (IL) block sets the working fluid liquid properties of your isothermal liquid network. The available predefined fluids are:

You can also model dissolved air in the system as a function of pressure. If you would like to specify your own working fluid properties, use the Foundation Library Isothermal Liquid Properties (IL) block. If you do not specify a fluid, the system defaults will apply. See Specify Fluid Properties for more details.

Fluid Properties Range

Water

Water properties are provided between the triple point, when the fluid temperature and pressure reach 273.160 K and 611.657 Pa, and the critical point, when the fluid temperature reaches 647.096 K. Pmin is set by the triple point or the saturation pressure, whichever is greater.

Ethylene-, Propylene-, and Glycerol-Water Mixtures

The properties for ethylene-glycol, propylene-glycol, and glycerol are provided for temperatures above the solution freezing point. Note that the displayed minimum temperature when visualizing properties may be lower than the fluid freezing point; displayed temperatures are not updated for different mixture concentrations.

When specifying the mixture, you can define the concentration of ethylene glycol, propylene glycol, or glycerol to water by mass fraction or volume fraction in the Concentration type parameter.

Properties are available for concentration by mass between 0 and 0.6 and by volume between 0 and 1 for ethylene glycol; for concentration by mass between 0 and 0.6 and by volume between 0.1 and 0.6 for propylene glycol; and for concentration by mass between 0 and 0.6 for glycerol. Glycerol concentration by volume is not available.

The properties are stored as a function of temperature and concentration. All properties, except for density and the thermal expansion coefficient α are maintained as constants for a range of pressures.

Seawater

Seawater properties are provided for temperatures between 273.15 K and 393.15 K and for pressures above the system saturation pressure. The salinity concentration can range from 0 to 0.12 by mass.

The properties are stored as tabulated data with respect to pressure and temperature. The data is derived from MIT's Seawater software. For more information, see: https://web.mit.edu/seawater/

Aviation Fuel Jet-A

The properties provided are for a general, representative fuel mixture based on Jet-A-4658 and Jet-A-3638 surrogates. The properties are provided at temperatures between 222.22 K and 645.61 K and pressures above the saturation point.

The properties are stored as tabulated data with respect to pressure and temperature.

Diesel Fuel

Diesel properties are provided for temperatures between 238.20 K and 690.97 K and for pressures above the saturation point.

SAE 5W-30

SAE 5W-30 properties are provided for temperatures between 235.15 K and 473.15 K and for pressures above 0.01 MPa. The properties at the system temperature and atmospheric pressure are based on measurements for temperatures between 29.85 °C and 74.85 °C (303 K to 348 K) and pressures between 7 MPa and 87 MPa. The block uses curve fits to define properties in extrapolated regions.

Dissolved Air

You can optionally model air dissolved into the liquid system. Setting Air dissolution model to On models dissolution between Atmospheric pressure and the Pressure at which all entrained air is dissolved by Henry's law. For more information, see Fluid Models with Entrained Air.

Visualizing Fluid Properties

To visualize the fluid density and bulk modulus in your network, right-click on the Isothermal Liquid Predefined Properties (IL) block and select Fluids > Plot Fluid Properties:

Use the Reload Data button to regenerate the plot whenever the fluid selection or fluid parameters change.

Examples

Pressure Control Solenoid

Pressure Control Solenoid

Model, parameterize, and test a pressure control solenoid valve. This example also generates a plot of the relationship between applied solenoid force and the resulting actuator port pressure.

Open Model

Ports

Conserving

expand all

Isothermal liquid conserving port that connects the block to the network. This port connects to any point on an isothermal liquid connection line within a block diagram. When you connect the Isothermal Liquid Predefined Properties (IL) block to a network line, the liquid properties are propagated to all blocks in the circuit.

Parameters

expand all

Liquid

Choice of working fluid in the system.

Concentration of salt in water by mass.

Dependencies

To enable this parameter, set Isothermal liquid to Seawater (MIT).

Whether the solute is measured in water by mass or volume.

Dependencies

To enable this parameter, set Isothermal liquid to:

  • Ethylene glycol and water mixture.

  • Propylene glycol and water mixture.

Fraction of ethylene glycol in water, by volume.

Dependencies

To enable this parameter, set Isothermal liquid to Ethylene glycol and water mixture and Concentration type to Volume fraction.

Fraction of ethylene glycol in water, by mass.

Dependencies

To enable this parameter, set Isothermal liquid to Ethylene glycol and water mixture and Concentration type to Mass fraction.

Solution bulk modulus at atmospheric pressure.

Dependencies

To enable this parameter, set Isothermal liquid to:

  • Ethylene glycol and water mixture.

  • Propylene glycol and water mixture.

  • Glycerol and water mixture.

Lower pressure limit during simulations. The Atmospheric pressure must greater than or equal to the Minimum valid pressure.

Dependencies

To enable this parameter, set Isothermal liquid to:

  • Ethylene glycol and water mixture.

  • Propylene glycol and water mixture.

  • Glycerol and water mixture.

Fraction of propylene glycol in water, by volume.

Dependencies

To enable this parameter, set Isothermal liquid to Propylene glycol and water mixture and Concentration type to Volume fraction.

Fraction of propylene glycol in water, by mass.

Dependencies

To enable this parameter, set Isothermal liquid to Propylene glycol and water mixture and Concentration type to Mass fraction.

Fraction of glycerol in water, by mass.

Dependencies

To enable this parameter, set Isothermal liquid to Glycerol and water mixture.

Isothermal liquid network temperature.

Correction factor for fluids diverging from the clean fluid standard viscosity.

Environmental pressure of the system.

Select what happens if the fluid pressure goes beyond the valid range during simulation:

  • None ― The block does not return an error if the properties go out of range.

  • Warning ― The block issues a warning, but continues the simulation.

  • Error ― The block returns an error and stops the simulation.

Entrained Air

Air entrainment in fluid network at atmospheric pressure.

Exponent of the equation that governs the polytropic process relating fluid pressure and volume.

Air density at the pressure defined in the Atmospheric pressure parameter.

Whether to account for of air dissolution into the fluid network. Air dissolution into the liquid is modeled between the Atmospheric pressure and the Pressure at which all entrained air is dissolved by Henry's Law.

Upper pressure limit for air entrainment into the fluid.

Dependencies

To enable this parameter, set Air dissolution model to On.

References

[1] Massachusetts Institute of Technology (MIT), Thermophysical properties of seawater database. http://web.mit.edu/seawater.

[2] K.G. Nayar, M.H. Sharqawy, L.D. Banchik, J.H. Lienhard V. "Thermophysical properties of seawater: A review and new correlations that include pressure dependence." Desalination 390 (July 2016): 1-24.

[3] M.H. Sharqawy, J.H. Lienhard V, S.M. Zubair. "Thermophysical properties of seawater: A review of existing correlations and data." Desalination and Water Treatment 16, no. 1-3 (april 2010): 354-380.

[4] I.H. Bell, J. Wronski, S. Quoilin, V. Lemort. "Pure and Pseudo-pure Fluid Thermophysical Property Evaluation and the Open-Source Thermophysical Property Library CoolProp." Industrial & Engineering Chemistry Research 53, no. 6 (February 12, 2014): 2498–2508.

Extended Capabilities

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

Version History

Introduced in R2020a

expand all

See Also

|

Topics