aerosandbox.atmosphere.thermodynamics.gas

Module Contents

Classes

PerfectGas

Provides a class for an ideal, calorically perfect gas.

Attributes

universal_gas_constant
g

aerosandbox.atmosphere.thermodynamics.gas.universal_gas_constant = 8.31432

class aerosandbox.atmosphere.thermodynamics.gas.PerfectGas(pressure=101325, temperature=273.15 + 15, specific_heat_constant_pressure=1006, specific_heat_constant_volume=717, molecular_mass=0.0289644, effective_collision_diameter=3.65e-10)

Provides a class for an ideal, calorically perfect gas.

Specifically, this gas:

• Has PV = nRT (ideal)

• Has constant heat capacities C_V, C_P (independent of temperature and pressure).

• Is in thermodynamic equilibrium

• Is not chemically reacting

• Has internal energy and enthalpy purely as functions of temperature

Parameters:

• pressure (Union[float, aerosandbox.numpy.ndarray]) –

• temperature (Union[float, aerosandbox.numpy.ndarray]) –

• specific_heat_constant_pressure (float) –

• specific_heat_constant_volume (float) –

• molecular_mass (float) –

• effective_collision_diameter (float) –

property density

property speed_of_sound

property specific_gas_constant

property ratio_of_specific_heats

property specific_volume

Gives the specific volume, often denoted v.

(Note the lowercase; “V” is often the volume of a specific amount of gas, and this presents a potential point of confusion.)

property specific_enthalpy

Gives the specific enthalpy, often denoted h.

Enthalpy here is in units of J/kg.

property specific_internal_energy

Gives the specific internal energy, often denoted u.

Internal energy here is in units of J/kg.

__repr__()

Return repr(self).

Return type:

str

specific_enthalpy_change(start_temperature, end_temperature)

Returns the change in specific enthalpy that would occur from a given temperature change via a thermodynamic process.

Parameters:

• start_temperature – Starting temperature [K]

• end_temperature – Ending temperature [K]

Returns: The change in specific enthalpy, in J/kg.

specific_internal_energy_change(start_temperature, end_temperature)

Returns the change in specific internal energy that would occur from a given temperature change via a thermodynamic process.

Parameters:

• start_temperature – Starting temperature [K]

• end_temperature – Ending temperature [K]

Returns: The change in specific internal energy, in J/kg.

process(process='isentropic', new_pressure=None, new_temperature=None, new_density=None, enthalpy_addition_at_constant_pressure=None, enthalpy_addition_at_constant_volume=None, polytropic_n=None, inplace=False)

Puts this gas under a thermodynamic process.

Equations here: https://en.wikipedia.org/wiki/Ideal_gas_law

Parameters:

• process (str) –

  Type of process. One of:

  • ”isobaric”

  • ”isochoric”

  • ”isothermal”

  • ”isentropic”

  • ”polytropic”

  The process must be specified.

• arguments (You must specifiy exactly one of the following) –

  • new_pressure: the new pressure after the process [Pa].

  • new_temperature: the new temperature after the process [K]

  • new_density: the new density after the process [kg/m^3]

  • enthalpy_addition_at_constant_pressure: [J/kg]

  • enthalpy_addition_at_constant_volume: [J/kg]

• polytropic_n (float) – If you specified the process type to be “polytropic”, you must provide the polytropic index

• (Reminder (n to be used here.) – PV^n = constant)

• inplace – Specifies whether to return the result in-place or to allocate a new PerfectGas object in memory

• result. (for the) –

• new_pressure (float) –

• new_temperature (float) –

• new_density (float) –

• enthalpy_addition_at_constant_pressure (float) –

• enthalpy_addition_at_constant_volume (float) –

Returns:

If inplace is False (default), returns a new PerfectGas object that represents the gas after the change.

If inplace is True, nothing is returned.

Return type:

PerfectGas

aerosandbox.atmosphere.thermodynamics.gas.g = []