gaspype.fluid

class gaspype.fluid(composition, fs=None, shape=None)

Bases: object

A class to represent a fluid defined by a composition of one or more species.

species

List of species names in the associated fluid_system

Type:

list[str]

array_composition

Array of the molar amounts of the species in the fluid

Type:

FloatArray

array_element_composition

Array of the element composition in the fluid

Type:

FloatArray

array_fractions

Array of the molar fractions of the species in the fluid

Type:

FloatArray

total

Array of the sums of the molar amount of all species

Type:

FloatArray | float

fs

Reference to the fluid_system used for this fluid

Type:

fluid_system

shape

Shape of the fluid array

Type:

_Shape

elements

List of elements in the fluid_system

Type:

list[str]

Instantiates a fluid.

Parameters:

• composition (dict[str, float] | list[float] | ndarray[tuple[Any, ...], dtype[float64]]) – A dict of species names with their composition, e.g. {‘O2’:0.5,’H2O’:0.5} or a list/numpy-array of compositions. The array can be multidimensional, the size of the last dimension must match the number of species defined for the fluid_system. The indices of the last dimension correspond to the indices in the active_species list of the fluid_system.

• fs (fluid_system | None) – Reference to a fluid_system. Is optional if composition is defined by a dict. If not specified a new fluid_system with the components from the dict is created.

• shape (Optional[Sequence[int]]) – Tuple or list for the dimensions the fluid array. Can only be used if composition argument is a dict. Otherwise the dimensions are specified by the composition argument.

get_G(t, p)

Get absolute gibbs free energy (H - TS)

Parameters:

• t (float | ndarray[tuple[Any, ...], dtype[float64]]) – Absolute temperature(s) in Kelvin. Fluid shape and shape of the temperature must be broadcastable

• p (float | ndarray[tuple[Any, ...], dtype[float64]]) – Pressures(s) in Pascal. Fluid shape and shape of the temperature must be broadcastable

Return type:

ndarray[tuple[Any, ...], dtype[float64]] | float

Returns:

Gibbs free energy in J

get_H(t)

Get absolute enthalpy of the fluid at the given temperature

Enthalpy is referenced to 25 °C and includes enthalpy of formation. Therefore the enthalpy of H2 and O2 is 0 at 25 °C, but the enthalpy of water vapor at 25 °C is −241 kJ/mol (enthalpy of formation).

Parameters:

t (float | ndarray[tuple[Any, ...], dtype[float64]]) – Absolute temperature(s) in Kelvin. Fluid shape and shape of the temperature must be broadcastable

Return type:

ndarray[tuple[Any, ...], dtype[float64]] | float

Returns:

Enthalpies in J

get_S(t, p)

Get absolute entropy of the fluid at the given temperature and pressure

Parameters:

t (float | ndarray[tuple[Any, ...], dtype[float64]]) – Absolute temperature(s) in Kelvin. Fluid shape and shape of the temperature must be broadcastable

Return type:

ndarray[tuple[Any, ...], dtype[float64]] | float

Returns:

Entropy in J/K

get_composition_dict()

Get a dict of the molar amount of each fluid species

Return type:

dict[str, float]

Returns:

Returns a dict of floats with the molar amount of each fluid species in mol

get_cp(t)

Get molar heat capacity at constant pressure

Parameters:

t (float | ndarray[tuple[Any, ...], dtype[float64]]) – Absolute temperature(s) in Kelvin. Fluid shape and shape of the temperature must be broadcastable

Return type:

ndarray[tuple[Any, ...], dtype[float64]] | float

Returns:

Heat capacity in J/mol/K

get_density(t, p)

Get mass based fluid density

Parameters:

• t (float | ndarray[tuple[Any, ...], dtype[float64]]) – Absolute temperature(s) in Kelvin. Fluid shape and shape of the temperature must be broadcastable

• p (float | ndarray[tuple[Any, ...], dtype[float64]]) – Pressure in Pa. Fluid shape and shape of the pressure must be broadcastable

Return type:

ndarray[tuple[Any, ...], dtype[float64]] | float

Returns:

Density of the fluid in kg/m³

get_fractions_dict()

Get a dict of the molar fractions of each fluid species

Return type:

dict[str, float]

Returns:

Returns a dict of floats with the molar fractions of each fluid species

get_g(t, p)

Get molar gibbs free energy (h - Ts)

Parameters:

• t (float | ndarray[tuple[Any, ...], dtype[float64]]) – Absolute temperature(s) in Kelvin. Fluid shape and shape of the temperature must be broadcastable

• p (float | ndarray[tuple[Any, ...], dtype[float64]]) – Pressures(s) in Pascal. Fluid shape and shape of the temperature must be broadcastable

Return type:

ndarray[tuple[Any, ...], dtype[float64]] | float

Returns:

Gibbs free energy in J/mol

get_g_rt(t, p)

Get specific gibbs free energy divided by RT: g/R/T == (h/T-s)/R

Parameters:

• t (float | ndarray[tuple[Any, ...], dtype[float64]]) – Absolute temperature(s) in Kelvin. Fluid shape and shape of the temperature must be broadcastable

• p (float | ndarray[tuple[Any, ...], dtype[float64]]) – Pressures(s) in Pascal. Fluid shape and shape of the temperature must be broadcastable

Return type:

ndarray[tuple[Any, ...], dtype[float64]] | float

Returns:

Gibbs free energy divided by RT (dimensionless)

get_h(t)

Get specific enthalpy of the fluid at the given temperature

Enthalpy is referenced to 25 °C and includes enthalpy of formation. Therefore the enthalpy of H2 and O2 is 0 at 25 °C, but the enthalpy of water vapor at 25 °C is −241 kJ/mol (enthalpy of formation).

Parameters:

t (float | ndarray[tuple[Any, ...], dtype[float64]]) – Absolute temperature(s) in Kelvin. Fluid shape and shape of the temperature must be broadcastable

Return type:

ndarray[tuple[Any, ...], dtype[float64]] | float

Returns:

Enthalpies in J/mol

get_mass()

Get Absolute fluid mass

Return type:

ndarray[tuple[Any, ...], dtype[float64]] | float

Returns:

Mass of the fluid in kg

get_molar_mass()

Get molar fluid mass

Return type:

ndarray[tuple[Any, ...], dtype[float64]] | float

Returns:

Mass of the fluid in kg/mol

get_s(t, p)

Get molar entropy of the fluid at the given temperature and pressure

Parameters:

t (float | ndarray[tuple[Any, ...], dtype[float64]]) – Absolute temperature(s) in Kelvin. Fluid shape and shape of the temperature must be broadcastable

Return type:

ndarray[tuple[Any, ...], dtype[float64]] | float

Returns:

Entropy in J/mol/K

get_v(t, p)

Get Absolute fluid volume

Parameters:

• t (float | ndarray[tuple[Any, ...], dtype[float64]]) – Absolute temperature(s) in Kelvin. Fluid shape and shape of the temperature must be broadcastable

• p (float | ndarray[tuple[Any, ...], dtype[float64]]) – Pressure in Pa. Fluid shape and shape of the pressure must be broadcastable

Return type:

ndarray[tuple[Any, ...], dtype[float64]] | float

Returns:

Volume of the fluid in m³

get_vm(t, p)

Get molar fluid volume

Parameters:

• t (float | ndarray[tuple[Any, ...], dtype[float64]]) – Absolute temperature(s) in Kelvin. Fluid shape and shape of the temperature must be broadcastable

• p (float | ndarray[tuple[Any, ...], dtype[float64]]) – Pressure in Pa. Fluid shape and shape of the pressure must be broadcastable

Return type:

ndarray[tuple[Any, ...], dtype[float64]] | float

Returns:

Molar volume of the fluid in m³/mol

get_x(species=None)

Get molar fractions of fluid species

Parameters:

species (str | list[str] | None) – A single species name, a list of species names or None for returning the molar fractions of all species

Return type:

ndarray[tuple[Any, ...], dtype[float64]]

Returns:

Returns an array of floats with the molar fractions of the species. If the a single species name is provided the return float array has the same dimensions as the fluid type. If a list or None is provided the return array has an additional dimension for the species.