def get_n(self, V=c.V0('m3'), P=c.P0('bar'), T=c.T0('K')):
"""Calculates the volume of an ideal gas
Parameters
----------
V : float, optional
Volume in m3. Default is standard volume
P : float, optional
Pressure in bar. Default is standard pressure
T : float, optional
Temperature in K. Default is standard temperature
Returns
-------
n : float
Number of moles in mol
"""
return P * V / c.R('m3 bar/mol/K') / T
def get_T(self, V=c.V0('m3'), P=c.P0('bar'), n=1.):
"""Calculates the volume of an ideal gas
Parameters
----------
V : float, optional
Volume in m3. Default is standard volume
P : float, optional
Pressure in bar. Default is standard pressure
n : float, optional
Number of moles (in mol). Default is 1 mol
Returns
-------
T : float
Temperature in K
"""
return P * V / c.R('m3 bar/mol/K') / n
def get_P(self, T=c.T0('K'), V=c.V0('m3'), n=1.):
"""Calculates the pressure of an ideal gas
Parameters
----------
T : float, optional
Temperature in K. Default is standard temperature
V : float, optional
Volume in m3. Default is standard volume
n : float, optional
Number of moles (in mol). Default is 1 mol
Returns
-------
P : float
Pressure in bar
"""
return n * c.R('m3 bar/mol/K') * T / V
def setUp(self):
unittest.TestCase.setUp(self)
# Testing Ideal Gas Model
CO2 = molecule('CO2')
CO2_PyMuTT_parameters = {
'trans_model':
trans.IdealTrans,
'n_degrees':
3,
'molecular_weight':
get_molecular_weight('CO2'),
'rot_model':
rot.RigidRotor,
'rot_temperatures':
rot.get_rot_temperatures_from_atoms(CO2, geometry='linear'),
'geometry':
'linear',
'symmetrynumber':
2,
'elec_model':
elec.IdealElec,
'potentialenergy':
-22.994202,
'spin':
0.,
'vib_model':
vib.HarmonicVib,
'vib_wavenumbers': [3360., 954., 954., 1890.],
}
CO2_ase_parameters = {
'atoms': CO2,
'potentialenergy': -22.994202,
'vib_energies': [c.wavenumber_to_energy(x) \
for x in CO2_PyMuTT_parameters['vib_wavenumbers']],
'geometry':'linear',
'symmetrynumber': 2,
'spin': 0.
}
self.CO2_PyMuTT = StatMech(**CO2_PyMuTT_parameters)
self.CO2_ASE = IdealGasThermo(**CO2_ase_parameters)
self.T0 = c.T0('K') # K
self.P0 = c.P0('Pa')
self.V0 = c.V0('m3')
def get_T(self, V=c.V0('m3'), P=c.P0('bar'), n=1.):
"""Calculates the volume of a van der Waals gas
Parameters
----------
V : float, optional
Volume in m3. Default is standard volume
P : float, optional
Pressure in bar. Default is standard pressure
n : float, optional
Number of moles (in mol). Default is 1 mol
Returns
-------
T : float
Temperature in K
"""
Vm = V / n
return (P*c.convert_unit(from_='bar', to='Pa') + self.a/Vm**2) \
*(Vm - self.b)/c.R('J/mol/K')
def get_P(self, T=c.T0('K'), V=c.V0('m3'), n=1.):
"""Calculates the pressure of a van der Waals gas
Parameters
----------
T : float, optional
Temperature in K. Default is standard temperature
V : float, optional
Volume in m3. Default is standard volume
n : float, optional
Number of moles (in mol). Default is 1 mol
Returns
-------
P : float
Pressure in bar
"""
Vm = V / n
return (c.R('J/mol/K')*T/(Vm - self.b) - self.a*(1./Vm)**2) \
*c.convert_unit(from_='Pa', to='bar')
def get_n(self, V=c.V0('m3'), P=c.P0('bar'), T=c.T0('K'), gas_phase=True):
"""Calculates the volume of a van der Waals gas
Parameters
----------
V : float, optional
Volume in m3. Default is standard volume
P : float, optional
Pressure in bar. Default is standard pressure
T : float, optional
Temperature in K. Default is standard temperature
gas_phase : bool, optional
Relevant if system is in vapor-liquid equilibrium. If True,
return the smaller moles (gas phase). If False, returns the
larger moles (liquid phase).
Returns
-------
n : float
Number of moles in mol
"""
return V / self.get_Vm(T=T, P=P, gas_phase=gas_phase)
def test_get_n(self):
self.assertAlmostEqual(
self.ideal_gas.get_n(T=c.T0('K'), V=c.V0('m3'), P=c.P0('bar')), 1.)
def test_get_P(self):
self.assertAlmostEqual(
self.ideal_gas.get_P(T=c.T0('K'), V=c.V0('m3'), n=1.), c.P0('bar'))
