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Class: Air

Description

The Air class represents the properties and constants for Air (approximate composition: 78% N₂, 21% O₂, 1% Ar/others).
It provides physical and thermodynamic properties required in process engineering simulations and calculations.

Properties

  • name (string): Air
  • formula (string): Mixture (≈ N₂₀.₇₈ O₂₀.₂₁ Ar₀.₀₁)
  • molecular_weight (float): 28.97 g/mol

Class Reference

class Air()

Parameters:
temperature: Temperature, default = Temperature(35,"C")
pressure: Pressure, default = Pressure(1,"atm")
density: Density, default = None
specific_heat: SpecificHeat, default = None
viscosity: Viscosity, default = None
thermal_conductivity: ThermalConductivity, default = None
vapor_pressure: Pressure, default = None
enthalpy: HeatOfVaporization, default = None

Methods

The properties of the Air class are calculated using the following methods, which are inherited from the base Component class.

  • phase(): Detects the phase of the substance ("gas" or "liquid") by comparing the system pressure to the calculated vapor pressure. (For air, this generally indicates "gas" at standard conditions.)
  • density():
    • Gas Phase: Calculates density using the Ideal Gas Law
    • Liquid Phase: Approximations possible under cryogenic conditions
  • specific_heat(): Calculates specific heat capacity (Cp​) as a polynomial function of temperature
  • viscosity():
    • Gas Phase: Calculates viscosity using Sutherland's Law
  • thermal_conductivity(): Calculates thermal conductivity (k) as a polynomial function of temperature
  • vapor_pressure(): Not typically applicable to air (mixture) but correlation can be used at cryogenic temperatures
  • enthalpy(): Calculates enthalpy using correlations based on temperature and reference state

Examples

from processpi.components import Air
from processpi.units import *

air = Air(temperature=Temperature(35, "C"))
print(air.density().to("kg/m3"))
print(air.viscosity().to("Pa·s"))
print(air.specific_heat().to("J/kgK"))
print(air.thermal_conductivity().to("W/mK"))
print(air.enthalpy().to("J/kg"))