def enthalpyvap(temp=None,
pres=None,
dvap=None,
dliq=None,
chkvals=False,
chktol=_CHKTOL,
temp0=None,
dvap0=None,
dliq0=None,
chkbnd=False,
mathargs=None):
"""Calculate water vapour enthalpy.
Calculate the enthalpy of water vapour for liquid water and water
vapour in equilibrium.
:arg temp: Temperature in K.
:type temp: float or None
:arg pres: Pressure in Pa.
:type pres: float or None
:arg dvap: Water vapour density in kg/m3. If unknown, pass None
(default) and it will be calculated.
:type dvap: float or None
:arg dliq: Liquid water density in kg/m3. If unknown, pass None
(default) and it will be calculated.
:type dliq: float or None
:arg bool chkvals: If True (default False) and all values are given,
this function will calculate the disequilibrium and raise a
warning if the results are not within a given tolerance.
:arg float chktol: Tolerance to use when checking values (default
_CHKTOL).
:arg temp0: Initial guess for the temperature in K. If None (default)
then `_approx_p` is used.
:type temp0: float or None
:arg dvap0: Initial guess for the water vapour density in kg/m3. If
None (default) then `_approx_t` is used.
:type dvap0: float or None
:arg dliq0: Initial guess for the liquid water density in kg/m3. If
None (default) then `_approx_t` is used.
:type dliq0: float or None
:arg bool chkbnd: If True then warnings are raised when the given
values are valid but outside the recommended bounds (default
False).
:arg mathargs: Keyword arguments to the root-finder
:func:`_newton <maths3.newton>` (e.g. maxiter, rtol). If None
(default) then no arguments are passed and default parameters
will be used.
:returns: Enthalpy in J/kg.
:raises ValueError: If neither of temp or pres is provided.
:raises ValueError: If the temperature is above the critical point.
:raises RuntimeWarning: If the relative disequilibrium is more than
chktol, if chkvals is True and all values are given.
:Examples:
>>> enthalpyvap(temp=300.)
2549854.10109
>>> enthalpyvap(pres=1e4)
2583858.67179
"""
temp, pres, dvap, dliq = eq_tp(temp=temp,
pres=pres,
dvap=dvap,
dliq=dliq,
chkvals=chkvals,
chktol=chktol,
temp0=temp0,
dvap0=dvap0,
dliq0=dliq0,
chkbnd=chkbnd,
mathargs=mathargs)
hv = flu2.enthalpy(temp, dvap)
return hv
def enthalpyevap(salt=None,airf=None,temp=None,pres=None,dhum=None,
dliq=None,chkvals=False,chktol=_CHKTOL,salt0=None,airf0=None,
temp0=None,pres0=None,dhum0=None,dliq0=None,chkbnd=False,
useext=False,mathargs=None):
"""Calculate sea-air enthalpy of evaporation.
Calculate the specific enthalpy of evaporation for sea-air.
:arg salt: Salinity in kg/kg. If unknown, pass None (default) and it
will be calculated.
:type salt: float or None
:arg airf: Humid air dry fraction in kg/kg. If unknown, pass None
(default) and it will be calculated.
:type airf: float or None
:arg temp: Temperature in K. If unknown, pass None (default) and it
will be calculated.
:type temp: float or None
:arg pres: Pressure in Pa. If unknown, pass None (default) and it
will be calculated.
:type pres: float or None
:arg dliq: Seawater liquid water density in kg/m3. If unknown, pass
None (default) and it will be calculated.
:type dliq: float or None
:arg dhum: Humid air density in kg/m3. If unknown, pass None
(default) and it will be calculated.
:type dhum: float or None
:arg bool chkvals: If True (default False) and all values are given,
this function will calculate the disequilibrium and raise a
warning if the results are not within a given tolerance.
:arg float chktol: Tolerance to use when checking values (default
_CHKTOL).
:arg salt0: Initial guess for the salinity in kg/kg. If None
(default) then the appropriate `_approx_*` is used.
:type salt0: float or None
:arg airf0: Initial guess for the humid air dry fraction in kg/kg.
If None (default) then the appropriate `_approx_*` is used.
:type airf0: float or None
:arg temp0: Initial guess for the temperature in K. If None
(default) then the appropriate `_approx_*` is used.
:type temp0: float or None
:arg pres0: Initial guess for the pressure in Pa. If None (default)
then the appropriate `_approx_*` is used.
:type pres0: float or None
:arg dliq0: Initial guess for the liquid water density in kg/m3. If
None (default) then `flu3a._dliq_default` is used.
:type dliq0: float or None
:arg dhum0: Initial guess for the liquid water density in kg/m3. If
None (default) then the appropriate `_approx_*` is used.
:type dhum0: float or None
:arg bool chkbnd: If True then warnings are raised when the given
values are valid but outside the recommended bounds (default
False).
:arg bool useext: If False (default) then the salt contribution is
calculated from _GSCOEFFS; if True, from _GSCOEFFS_EXT.
:arg mathargs: Keyword arguments to the root-finder
:func:`_newton <maths3.newton>` (e.g. maxiter, rtol). If None
(default) then no arguments are passed and default parameters
will be used.
:returns: Enthalpy in J/kg.
:raises ValueError: If fewer than three of salt, airf, temp, and
pres are provided.
:raises RuntimeWarning: If the relative disequilibrium is more than
chktol, if chkvals is True and all values are given.
:Examples:
>>> enthalpyevap(salt=0.035,airf=0.99,pres=1e5)
2464765.77588
>>> enthalpyevap(salt=0.035,temp=300.,pres=1e5)
2434570.55229
"""
salt, airf, temp, pres, dhum, dliq = eq_satp(salt=salt,airf=airf,temp=temp,
pres=pres,dhum=dhum,dliq=dliq,chkvals=chkvals,chktol=chktol,salt0=salt0,
airf0=airf0,temp0=temp0,pres0=pres0,dhum0=dhum0,dliq0=dliq0,
chkbnd=chkbnd,useext=useext,mathargs=mathargs)
# Calculate water vapour enthalpy
fh = _air_f(0,0,0,airf,temp,dhum)
fh_a = _air_f(1,0,0,airf,temp,dhum)
fh_t = _air_f(0,1,0,airf,temp,dhum)
fh_d = _air_f(0,0,1,airf,temp,dhum)
fh_at = _air_f(1,1,0,airf,temp,dhum)
fh_ad = _air_f(1,0,1,airf,temp,dhum)
fh_td = _air_f(0,1,1,airf,temp,dhum)
fh_dd = _air_f(0,0,2,airf,temp,dhum)
ch = 2*fh_d + dhum*fh_dd
hh = fh - temp*fh_t + dhum*fh_d
hh_a = fh_a - temp*fh_at + temp*dhum/ch*fh_ad*fh_td
hv = hh - airf*hh_a
hl = flu2.enthalpy(temp,dliq)
# Treat pure water case separately to avoid numerical errors
if salt == 0:
hevap = hv - hl
return hevap
gs = _sal_g(0,0,0,salt,temp,pres,useext=useext)
gs_s = _sal_g(1,0,0,salt,temp,pres,useext=useext)
gs_t = _sal_g(0,1,0,salt,temp,pres,useext=useext)
gs_st = _sal_g(1,1,0,salt,temp,pres,useext=useext)
hls = gs - temp*gs_t - salt*(gs_s - temp*gs_st)
hevap = hv - hl - hls
return hevap
def enthalpysubl(temp=None,
pres=None,
dvap=None,
chkvals=False,
chktol=_CHKTOL,
temp0=None,
pres0=None,
dvap0=None,
chkbnd=False,
mathargs=None):
"""Calculate enthalpy of sublimation.
Calculate the specific enthalpy of sublimation.
:arg temp: Temperature in K.
:type temp: float or None
:arg pres: Pressure in Pa.
:type pres: float or None
:arg dvap: Water vapour density in kg/m3. If unknown, pass None
(default) and it will be calculated.
:type dvap: float or None
:arg bool chkvals: If True (default False) and all values are given,
this function will calculate the disequilibrium and raise a
warning if the results are not within a given tolerance.
:arg float chktol: Tolerance to use when checking values (default
_CHKTOL).
:arg temp0: Initial guess for the temperature in K. If None
(default) then `_approx_p` is used.
:type temp0: float or None
:arg pres0: Initial guess for the pressure in Pa. If None (default)
then `_approx_t` is used.
:type pres0: float or None
:arg dvap0: Initial guess for the water vapour density in kg/m3. If
None (default) then `_approx_t` or `_approx_p` is used.
:type dvap0: float or None
:arg bool chkbnd: If True then warnings are raised when the given
values are valid but outside the recommended bounds (default
False).
:arg mathargs: Keyword arguments to the root-finder
:func:`_newton <maths3.newton>` (e.g. maxiter, rtol). If None
(default) then no arguments are passed and default parameters
will be used.
:returns: Enthalpy in J/kg.
:raises ValueError: If neither of temp or pres is provided.
:raises RuntimeWarning: If the relative disequilibrium is more than
chktol, if chkvals is True and all values are given.
:Examples:
>>> enthalpysubl(temp=270.)
2835165.65442
>>> enthalpysubl(pres=100.)
2838101.44416
"""
temp, pres, dvap = eq_tp(temp=temp,
pres=pres,
dvap=dvap,
chkvals=chkvals,
chktol=chktol,
temp0=temp0,
pres0=pres0,
dvap0=dvap0,
chkbnd=chkbnd,
mathargs=mathargs)
hv = flu2.enthalpy(temp, dvap)
hi = ice2.enthalpy(temp, pres)
hsubl = hv - hi
return hsubl