componentLibrary/pneumatics/gasModels/ConstantProperties - MapleSim Help
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Constant Properties

This gas property assumes constant fluid properties with no enthalpy flow between the components.

Description

Equations

Gas Parameters

Global Settings

Description

This property block assumes constant values for the thermodynamic properties of gas in the simulation. The system follows the assumptions below.

• 

Ideal Gas Law equation is used to calculate the gas properties for models.

• 

The specific enthalpy flow is assumed to be constant throughout the simulation. The enthalpy into the component is calculated based on the environmental temperature and the specific heat capacity, c__p.

• 

The default gas properties assumed in this block are for the air.

Note:  Place this component at the same level as the other pneumatic components or subsystem to which the gas model is applied. If multiple models are created in the same canvas referring to different gas properties then each component must be provided with the respective gas property block name. This can be done by clearing the Use default medium (fluidModel1) check box in the component properties. If Use default medium (fluidModel1) is selected, the component will refer to the default air properties.

Equations

Specific heat capacity at constant pressure, c__p = R + c__v Gas Ratio, γ = c__pc__vReference Density, ρ__0 = fp,T, c__p  Specific Enthalpy , hflow = fp,T, c__p 

ρ__= P__xRT__env h__flow = C__pT__env

Parameters

Fluid Properties

Name

Default

Units

Description

Modelica ID

R

288

JkgK

Specific Gas constant

R

c__v

718

JkgK

Specific heat capacity at constant volume

cv

μ

0.000001458

Pa·s

Reference Dynamic Viscosity

mu

Global Settings

The global settings are used by most of the components in the library.  All the parameters defined in this block can be accessed by each component.

Name

Default

Units

Description

Modelica ID

patm

101325

Pa

Atmospheric pressure

p_atm

T__env

293.15

K

Environmental temperature

T_env

b__min

0.0001

Minimum allowable critical pressure ratio

b_min

b__max

0.8

Maximum allowable critical pressure ratio

b_max

 

See Also

Pneumatics Library