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():
- Gas Phase: Ideal-gas heat capacity (Cp), DIPPR Eq. 107 with the constants of Perry's Chemical Engineers' Handbook, 8th ed., Table 2-156
- Liquid Phase: Polynomial function of temperature (Perry's Table 2-153)
viscosity():
- Gas Phase: Calculates viscosity using Sutherland's Law
thermal_conductivity():
- Gas Phase: Vapor thermal conductivity (k), DIPPR Eq. 102 with the constants of Perry's 8th ed., Table 2-314
- Liquid Phase: Polynomial function of temperature (Perry's Table 2-315)
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"))

Class: Air