thermo/activity.py
def identify_phase(T, P, Tm=None, Tb=None, Tc=None, Psat=None):
    r'''Determines the phase of a one-species chemical system according to
    basic rules, using whatever information is available. Considers only the
    phases liquid, solid, and gas; does not consider two-phase
    scenarios, as should occurs between phase boundaries.

    * If the melting temperature is known and the temperature is under or equal
      to it, consider it a solid.
    * If the critical temperature is known and the temperature is greater or
      equal to it, consider it a gas.
    * If the vapor pressure at `T` is known and the pressure is under or equal
      to it, consider it a gas. If the pressure is greater than the vapor
      pressure, consider it a liquid.
    * If the melting temperature, critical temperature, and vapor pressure are
      not known, attempt to use the boiling point to provide phase information.
      If the pressure is between 90 kPa and 110 kPa (approximately normal),
      consider it a liquid if it is under the boiling temperature and a gas if
      above the boiling temperature.
    * If the pressure is above 110 kPa and the boiling temperature is known,
      consider it a liquid if the temperature is under the boiling temperature.
    * Return None otherwise.

    Parameters
    ----------
    T : float
        Temperature, [K]
    P : float
        Pressure, [Pa]
    Tm : float, optional
        Normal melting temperature, [K]
    Tb : float, optional
        Normal boiling point, [K]
    Tc : float, optional
        Critical temperature, [K]
    Psat : float, optional
        Vapor pressure of the fluid at `T`, [Pa]

    Returns
    -------
    phase : str
        Either 's', 'l', 'g', or None if the phase cannot be determined

    Notes
    -----
    No special attential is paid to any phase transition. For the case where
    the melting point is not provided, the possibility of the fluid being solid
    is simply ignored.

    Examples
    --------
    >>> identify_phase(T=280, P=101325, Tm=273.15, Psat=991)
    'l'
    '''
    if Tm and T <= Tm:
        return 's'
    elif Tc and T >= Tc:
        # No special return value for the critical point
        return 'g'
    elif Psat:
        # Do not allow co-existence of phases; transition to 'l' directly under
        if P <= Psat:
            return 'g'
        elif P > Psat:
            return 'l'
    elif Tb:
        # Crude attempt to model phases without Psat
        # Treat Tb as holding from 90 kPa to 110 kPa
        if 9E4 < P < 1.1E5:
            if T < Tb:
                return  'l'
            else:
                return 'g'
        elif P > 1.1E5 and T <= Tb:
            # For the higher-pressure case, it is definitely liquid if under Tb
            # Above the normal boiling point, impossible to say - return None
            return 'l'
        else:
            return None
    else:
        return None
def identify_phase(T, P, Tm=None, Tb=None, Tc=None, Psat=None):
    r'''Determines the phase of a one-species chemical system according to
    basic rules, using whatever information is available. Considers only the
    phases liquid, solid, and gas; does not consider two-phase
    scenarios, as should occurs between phase boundaries.

    * If the melting temperature is known and the temperature is under or equal
      to it, consider it a solid.
    * If the critical temperature is known and the temperature is greater or
      equal to it, consider it a gas.
    * If the vapor pressure at `T` is known and the pressure is under or equal
      to it, consider it a gas. If the pressure is greater than the vapor
      pressure, consider it a liquid.
    * If the melting temperature, critical temperature, and vapor pressure are
      not known, attempt to use the boiling point to provide phase information.
      If the pressure is between 90 kPa and 110 kPa (approximately normal),
      consider it a liquid if it is under the boiling temperature and a gas if
      above the boiling temperature.
    * If the pressure is above 110 kPa and the boiling temperature is known,
      consider it a liquid if the temperature is under the boiling temperature.
    * Return None otherwise.

    Parameters
    ----------
    T : float
        Temperature, [K]
    P : float
        Pressure, [Pa]
    Tm : float, optional
        Normal melting temperature, [K]
    Tb : float, optional
        Normal boiling point, [K]
    Tc : float, optional
        Critical temperature, [K]
    Psat : float, optional
        Vapor pressure of the fluid at `T`, [Pa]

    Returns
    -------
    phase : str
        Either 's', 'l', 'g', or None if the phase cannot be determined

    Notes
    -----
    No special attential is paid to any phase transition. For the case where
    the melting point is not provided, the possibility of the fluid being solid
    is simply ignored.

    Examples
    --------
    >>> identify_phase(T=280, P=101325, Tm=273.15, Psat=991)
    'l'
    '''
    if Tm and T <= Tm:
        return 's'
    elif Tc and T >= Tc:
        # No special return value for the critical point
        return 'g'
    elif Psat:
        # Do not allow co-existence of phases; transition to 'l' directly under
        if P <= Psat:
            return 'g'
        elif P > Psat:
            return 'l'
    elif Tb:
        # Crude attempt to model phases without Psat
        # Treat Tb as holding from 90 kPa to 110 kPa
        if 9E4 < P < 1.1E5:
            if T < Tb:
                return  'l'
            else:
                return 'g'
        elif P > 1.1E5 and T <= Tb:
            # For the higher-pressure case, it is definitely liquid if under Tb
            # Above the normal boiling point, impossible to say - return None
            return 'l'
        else:
            return None
    else:
        return None
def identify_phase ( T , P , Tm = None , Tb = None , Tc = None , Psat = None ) : if Tm and T <= Tm : return 's' elif Tc and T >= Tc : # No special return value for the critical point return 'g' elif Psat : # Do not allow co-existence of phases; transition to 'l' directly under if P <= Psat : return 'g' elif P > Psat : return 'l' elif Tb : # Crude attempt to model phases without Psat # Treat Tb as holding from 90 kPa to 110 kPa if 9E4 < P < 1.1E5 : if T < Tb : return 'l' else : return 'g' elif P > 1.1E5 and T <= Tb : # For the higher-pressure case, it is definitely liquid if under Tb # Above the normal boiling point, impossible to say - return None return 'l' else : return None else : return None
r'''Determines the phase of a one-species chemical system according to
    basic rules, using whatever information is available. Considers only the
    phases liquid, solid, and gas; does not consider two-phase
    scenarios, as should occurs between phase boundaries.

    * If the melting temperature is known and the temperature is under or equal
      to it, consider it a solid.
    * If the critical temperature is known and the temperature is greater or
      equal to it, consider it a gas.
    * If the vapor pressure at `T` is known and the pressure is under or equal
      to it, consider it a gas. If the pressure is greater than the vapor
      pressure, consider it a liquid.
    * If the melting temperature, critical temperature, and vapor pressure are
      not known, attempt to use the boiling point to provide phase information.
      If the pressure is between 90 kPa and 110 kPa (approximately normal),
      consider it a liquid if it is under the boiling temperature and a gas if
      above the boiling temperature.
    * If the pressure is above 110 kPa and the boiling temperature is known,
      consider it a liquid if the temperature is under the boiling temperature.
    * Return None otherwise.

    Parameters
    ----------
    T : float
        Temperature, [K]
    P : float
        Pressure, [Pa]
    Tm : float, optional
        Normal melting temperature, [K]
    Tb : float, optional
        Normal boiling point, [K]
    Tc : float, optional
        Critical temperature, [K]
    Psat : float, optional
        Vapor pressure of the fluid at `T`, [Pa]

    Returns
    -------
    phase : str
        Either 's', 'l', 'g', or None if the phase cannot be determined

    Notes
    -----
    No special attential is paid to any phase transition. For the case where
    the melting point is not provided, the possibility of the fluid being solid
    is simply ignored.

    Examples
    --------
    >>> identify_phase(T=280, P=101325, Tm=273.15, Psat=991)
    'l'
r Determines the phase of a one - species chemical system according to basic rules using whatever information is available . Considers only the phases liquid solid and gas ; does not consider two - phase scenarios as should occurs between phase boundaries .