Mean Free Path¶

Particula Index / Particula / Gas / Properties / Mean Free Path

Auto-generated documentation for particula.gas.properties.mean_free_path module.

get_molecule_mean_free_path¶

Calculate the mean free path of a gas molecule in air.

This function calculates λ based on the input conditions. If dynamic_viscosity is not provided, it is computed via get_dynamic_viscosity(temperature).

λ = (2 × μ / P) / √(8 × M / (π × R × T))
- λ is Mean free path [m].
- μ is Dynamic viscosity [Pa·s].
- P is Gas pressure [Pa].
- M is Molar mass [kg/mol].
- R is Universal gas constant [J/(mol·K)].
- T is Gas temperature [K].

Arguments¶

molar_mass : The molar mass of the gas molecule [kg/mol].
temperature : The temperature of the gas [K].
pressure : The pressure of the gas [Pa].
dynamic_viscosity : The dynamic viscosity of the gas [Pa·s]. If None, it will be calculated based on the temperature.

Returns¶

Mean free path of the gas molecule in meters (m).

Examples¶

Example usage

import particula as par
par.gas.get_molecule_mean_free_path()
# Returns mean free path at ~298K and 101325Pa, ~6.5e-8 m

References¶

"Mean Free Path," Wikipedia, The Free Encyclopedia. https://en.wikipedia.org/wiki/Mean_free_path

Signature¶

def get_molecule_mean_free_path(
    molar_mass: ignore = MOLECULAR_WEIGHT_AIR,
    temperature: float = 298.15,
    pressure: float = 101325,
    dynamic_viscosity: Optional[float] = None,
) -> Union[float, NDArray[np.float64]]: ...