Liquid

Basic graphical layout of input/output block

    Liquid

Library

HydraulicsByFluidon/Media

Description

Model of a hydraulic liquid. The model provides the other components (e.g. pipes) with temperature- and pressure-dependent fluid properties. In order for the fluid properties to reach the other components, the liquid model must be connected to the hydraulic circuit.

The user can choose between the following liquids:

The model provides the following fluid properties as functions of pressure and temperature:
  • Density
  • Kinematic viscosity
  • Dynamic viscosity
  • Isothermal bulk modulus
  • Isentropic bulk modulus
  • Speed of sound
  • Specific heat at constant pressure
  • Isobaric thermal expansion coefficient
  • Thermal conductivity
As an example, the following diagram shows the variation of density with pressure and temperature for water.

Due to the used mathematical approach, the fluid properties are only valid within a limited range of temperatures and pressures. If the deviations from the actual fluid properties are too large, the custom fluid can be used.

If the effects of undissolved air are to be considered during the simulation, the user can provide the fraction of undissolved air at ambient pressure through the parameter Proportion of undissolved air. The stiffness of the gas bubbles is calculated based on the parameter Polytropic exponent which can assume values between 1.0 (isothermal change of state, slow compression/expansion) and 1.4 (isentropic change of state, fast compression/expansion).

Parameters

Liquid_0

NameLabelDescriptionData TypeValid Values

mo_fluidType

fluidType

Type of Liquid

Structure

mo_fluidType/choice1

HLP 46

Number

0
1

mo_fluidType/choice2

HLP 32

Number

0
1

mo_fluidType/choice3

Oil 5W30

Number

0
1

mo_fluidType/choice4

Pentosin CHF 11S

Number

0
1

mo_fluidType/choice5

Skydrol 5

Number

0
1

mo_fluidType/choice6

Water

Number

0
1

mo_fluidTemperature

fluidTemperature

Fluid temperature

Scalar

mo_proportionUndissolvedAir

proportionUndissolvedAir

Proportion of undissolved air

Scalar

mo_polytropicExponent

polytropicExponent

Polytropic exponent

Scalar

Ports

NameTypeDescriptionIO TypeNumber

fluidPort

implicit

Hydraulic port

input

1