import numpy as np
from openpnm.models.phase.mixtures import mixing_rule
from openpnm.models.phase import _phasedocs
__all__ = [
'water_correlation',
'gas_pure_st',
'gas_pure_gesmr',
'gas_mixture_hz',
'liquid_pure_ls',
'liquid_mixture_xweighted',
]
[docs]
@_phasedocs
def water_correlation(
phase,
T='pore.temperature',
salinity='pore.salinity'
):
r"""
Calculates viscosity of pure water or seawater at atmospheric pressure.
This correlation uses Eq. (22) given by Sharqawy et. al [1]. Values at
temperature higher than the normal boiling temperature are calculated
at the saturation pressure.
Parameters
----------
%(phase)s
%(T)s
%(salinity)s
Returns
-------
mu : ndarray
Array containing viscosity of water or seawater in [kg/m.s] or [Pa.s]
Notes
-----
T must be in K, and S in g of salt per kg of phase, or ppt (parts per
thousand)
VALIDITY: 273 < T < 453 K; 0 < S < 150 g/kg;
ACCURACY: 1.5 percent
References
----------
[1] Sharqawy M. H., Lienhard J. H., and Zubair, S. M., Desalination and
Water Treatment, 2010.
"""
T = phase[T]
if salinity in phase.keys():
S = phase[salinity]
else:
S = 0
TC = T-273.15
S = S/1000
a1 = 1.5700386464E-01
a2 = 6.4992620050E+01
a3 = -9.1296496657E+01
a4 = 4.2844324477E-05
mu_w = a4 + 1/(a1*(TC+a2)**2+a3)
a5 = 1.5409136040E+00
a6 = 1.9981117208E-02
a7 = -9.5203865864E-05
a8 = 7.9739318223E+00
a9 = -7.5614568881E-02
a10 = 4.7237011074E-04
A = a5 + a6*T + a7*T**2
B = a8 + a9*T + a10*T**2
mu_sw = mu_w*(1 + A*S + B*S**2)
value = mu_sw
return value
@_phasedocs
def air_correlation(
phase,
T='pore.temperature',
n_V='pore.molar_density',
):
r"""
Calculates the viscosity of air at given conditions
This model uses the correlation from [1].
Parameters
----------
%(phase)s
%(T)s
%(n_V)s
Returns
-------
References
----------
[1] I forget
"""
raise Exception("This function does not work yet")
# Get props from object
T = phase[T]
rho = phase[n_V]
# Declare given constants
MW = 28.9586 # g/mol
Tc = 132.6312 # K
rho_c = 10447.7 # mol/m3
sigma = 0.36 # nm
e_k = 103.3 # K
# Compute a few definitions
delta = rho/rho_c
T_star = T/e_k
tau = np.atleast_2d(Tc/T)
# Declare the summation variables
ind = np.atleast_2d([0, 1, 2, 3, 4]).T
N_i = np.atleast_2d([10.72, 1.122, 0.002019, -8.878, -0.02916]).T
t_i = np.atleast_2d([0.2, 0.05, 2.4, 0.6, 3.6]).T
d_i = np.atleast_2d([1, 4, 9, 1, 8]).T
b_i = np.atleast_2d([0.431, -0.4623, 0.08406, 0.005341, -0.00331]).T
gamma_i = np.atleast_2d([0, 0, 0, 1, 1]).T
# Start crunching numbers
omega = np.exp(np.sum(b_i*(np.atleast_2d(np.log(T_star))**(ind)), axis=0))
mu_o = 0.9266958*(MW*T)**0.5/((sigma**2) * omega)
temp = N_i * (tau**t_i) * (delta**d_i) * np.exp(-gamma_i*(delta**gamma_i))
mu_t = np.sum(temp, axis=0)
mu = mu_o + mu_t
return mu
[docs]
@_phasedocs
def gas_pure_st(
phase,
T='pore.temperature',
Tc='param.critical_temperature',
Pc='param.critical_pressure',
MW='param.molecular_weight',
):
r"""
Calculates the viscosity of a pure gas using the correlation in [1]
Parameters
----------
%(phase)s
%(T)s
%(Tc)s
%(Pc)s
%(MW)s
Returns
-------
References
----------
[1] Stiel and Thodos
"""
# stiel-thodos
T = phase[T]
Tc = phase[Tc]
Pc = phase[Pc]/101325
MW = phase[MW]
mu = np.zeros_like(T)
Tr = T/Tc
zeta = Tc**(1/6)/((MW**0.5)*(Pc**(2/3)))
mu_hi = (17.78e-5*(4.58*Tr - 1.67)**0.625)/zeta
mu_lo = (34e-5*Tr**0.94)/zeta
mask = Tr > 1.5
mu[mask] = mu_hi[mask]
mu[~mask] = mu_lo[~mask]
return mu/1000
[docs]
@_phasedocs
def gas_pure_gesmr(
phase,
T='pore.temperature',
Tc='param.critical_temperature',
Pc='param.critical_pressure',
MW='param.molecular_weight',
):
r"""
Calculates the viscosity of a pure gas using the correlation [1]
Parameters
----------
%(phase)s
%(T)s
%(Tc)s
%(Pc)s
%(MW)s
Returns
-------
References
----------
[1] Gharagheizi et al
"""
T = phase[T]
MW = phase[MW]
Pc = phase[Pc]
Tc = phase[Tc]
Tr = T/Tc
mu = (1e-5)*Pc*Tr + (0.091 - 0.477/MW)*T + \
MW*((1e-5)*Pc - 8.0*(MW**2)/(T**2))*(10.7639/Tc - 4.1929/T)
mu = mu*1e-7
mu = np.clip(mu, a_min=1e-7, a_max=np.inf)
return mu
[docs]
@_phasedocs
def gas_mixture_hz(
phase,
mus='pore.viscosity.*',
MWs='param.molecular_weight.*',
):
r"""
Computes the viscosity of a gas mixture using the correlation in [1]
Parameters
----------
%(phase)s
%(mus)s
%(MWs)s
Returns
-------
mu : ndarray
An ndarray of Np length containing the viscosity of the mixture in
each pore
References
----------
[1] Herning and Zipperer
"""
MWs = phase.get_comp_vals(MWs)
mus = phase.get_comp_vals(mus)
xs = phase['pore.mole_fraction']
num = 0.0
denom = 0.0
for k in xs.keys():
num += xs[k]*mus[k]*MWs[k]**0.5
denom += xs[k]*MWs[k]**0.5
mu = num/denom
return mu
[docs]
@_phasedocs
def liquid_pure_ls(
phase,
T='pore.temperature',
MW='param.molecular_weight',
Tc='param.critical_temperature',
Pc='param.critical_pressure',
omega='param.acentric_factor',
):
r"""
Computes the viscosity of a pure liquid using the correlation in [1]
Parameters
----------
%(phase)s
%(T)s
%(MW)s
%(Tc)s
%(Pc)s
%(omega)s
Returns
-------
mu : ndarray
An ndarray of Np length containing the viscosity of the mixture in
each pore
References
----------
[1] Letsou and Stiel
"""
T = phase[T]
MW = phase[MW]
Tc = phase[Tc]
Pc = phase[Pc]
omega = phase[omega]
Tr = T/Tc
zeta = 2173.424 * (Tc**(1/6))/((MW**(0.5))*(Pc**(2/3)))
zeta0 = (1.5174 - 2.135*Tr + 0.75*(Tr**2))*1e-5
zeta1 = (4.2552 - 7.674*Tr + 3.4*(Tr**2))*1e-5
mu = (zeta0 + omega*zeta1)/zeta
return mu
[docs]
def liquid_mixture_xweighted(
phase,
prop='pore.viscosity.*',
mode='logarithmic',
power=1,
):
return mixing_rule(phase=phase, prop=prop, mode=mode, power=power)
liquid_mixture_xweighted.__doc__ = mixing_rule.__doc__
