def initialise_target(c, key):
r"""
Return a starting value for pressure and enthalpy at inlet.
Parameters
----------
c : tespy.connections.connection.Connection
Connection to perform initialisation on.
key : str
Fluid property to retrieve.
Returns
-------
val : float
Starting value for pressure/enthalpy in SI units.
.. math::
val = \begin{cases}
10^6 & \text{key = 'p'}\\
h\left(p, x=0 \right) & \text{key = 'h' at inlet 1}\\
h\left(p, x=0.7 \right) & \text{key = 'h' at inlet 2}
\end{cases}
"""
if key == 'p':
return 10e5
elif key == 'h':
if c.target_id == 'in1':
return h_mix_pQ(c.get_flow(), 0)
else:
return h_mix_pQ(c.get_flow(), 0.7)
def initialise_source(self, c, key):
r"""
Returns a starting value for pressure and enthalpy at component's
outlet.
Parameters
----------
c : tespy.connections.connection
Connection to perform initialisation on.
key : str
Fluid property to retrieve.
Returns
-------
val : float
Starting value for pressure/enthalpy in SI units.
.. math::
val = \begin{cases}
10^6 & \text{key = 'p'}\\
h\left(p, x=0 \right) & \text{key = 'h' at outlet 1}\\
h\left(p, x=1 \right) & \text{key = 'h' at outlet 2}
\end{cases}
"""
if key == 'p':
return 10e5
elif key == 'h':
if c.s_id == 'out1':
return h_mix_pQ(c.to_flow(), 0)
else:
return h_mix_pQ(c.to_flow(), 1)
def outlet_states_func(self):
r"""
Calculate energy balance.
Returns
-------
residual : list
Residual values of outlet state equations.
.. math::
0 = h_{out,1} - h\left(p, x=0 \right)\\
0 = h_{out,2} - h\left(p, x=1 \right)
"""
return [
h_mix_pQ(self.outl[0].get_flow(), 0) - self.outl[0].h.val_SI,
h_mix_pQ(self.outl[1].get_flow(), 1) - self.outl[1].h.val_SI]
def equations(self):
r"""
Calculates vector vec_res with results of equations for this component.
Returns
-------
vec_res : list
Vector of residual values.
"""
vec_res = []
######################################################################
# eqations for fluid balance
vec_res += self.fluid_func()
######################################################################
# eqations for mass flow balance
vec_res += self.mass_flow_func()
######################################################################
# eqations for pressure
p = self.inl[0].p.val_SI
for c in [self.inl[1]] + self.outl:
vec_res += [p - c.p.val_SI]
######################################################################
# eqations for enthalpy
val = 0
for i in self.inl:
val += i.m.val_SI * i.h.val_SI
for o in self.outl:
val -= o.m.val_SI * o.h.val_SI
vec_res += [val]
######################################################################
# eqations for staturated fluid state at outlets
vec_res += [
h_mix_pQ(self.outl[0].to_flow(), 0) - self.outl[0].h.val_SI
]
vec_res += [
h_mix_pQ(self.outl[1].to_flow(), 1) - self.outl[1].h.val_SI
]
return vec_res
def equations(self):
r"""Calculate vector vec_res with results of equations."""
k = 0
######################################################################
# eqations for fluid balance
self.vec_res[k:k + self.num_nw_fluids * 2] = self.fluid_func()
k += self.num_nw_fluids * 2
######################################################################
# eqations for mass flow balance
self.vec_res[k] = self.mass_flow_func()
k += 1
######################################################################
# eqations for pressure
p = self.inl[0].p.val_SI
for c in [self.inl[1]] + self.outl:
self.vec_res[k] = p - c.p.val_SI
k += 1
######################################################################
# eqations for enthalpy
val = 0
for i in self.inl:
val += i.m.val_SI * i.h.val_SI
for o in self.outl:
val -= o.m.val_SI * o.h.val_SI
self.vec_res[k] = val
k += 1
######################################################################
# eqations for staturated fluid state at outlets
self.vec_res[k] = h_mix_pQ(
self.outl[0].to_flow(), 0) - self.outl[0].h.val_SI
k += 1
self.vec_res[k] = h_mix_pQ(
self.outl[1].to_flow(), 1) - self.outl[1].h.val_SI
k += 1
def saturated_gas_func(self):
r"""
Calculate hot side outlet state.
Returns
-------
residual : float
Residual value of equation
.. math::
0 = h_{out,1} - h\left(p_{out,1}, x=1 \right)
"""
return self.outl[0].h.val_SI - h_mix_pQ(self.outl[0].get_flow(), 1)
def overheating_func(self):
r"""
Equation for cold side outlet state.
Returns
-------
residual : float
Residual value of equation.
.. math::
0=h_{out,3} -h\left(p_{out,3}, x=1 \right)
Note
----
This equation is applied in case overheating is False!
"""
return self.outl[2].h.val_SI - h_mix_pQ(self.outl[2].get_flow(), 1)
def subcooling_func(self):
r"""
Equation for steam side outlet state.
Returns
-------
residual : float
Residual value of equation.
.. math::
0=h_{out,1} -h\left(p_{out,1}, x=0 \right)
Note
----
This equation is applied in case subcooling is False!
"""
return self.outl[0].h.val_SI - h_mix_pQ(self.outl[0].get_flow(), 0)
def equations(self):
r"""Calculate residual vector with results of equations."""
k = 0
######################################################################
# equations for fluid balance
self.residual[k:k + self.num_nw_fluids * 3] = self.fluid_func()
k += self.num_nw_fluids * 3
######################################################################
# equations for mass flow balance
self.residual[k:k + 3] = self.mass_flow_func()
k += 3
######################################################################
# equations for energy balance
self.residual[k] = self.energy_func()
k += 1
######################################################################
# equations for specified heat transfer
if self.Q.is_set:
self.residual[k] = (
self.inl[2].m.val_SI *
(self.outl[2].h.val_SI - self.inl[2].h.val_SI) - self.Q.val)
k += 1
######################################################################
# equations for specified pressure ratio at hot side 1
if self.pr1.is_set:
self.residual[k] = (self.pr1.val * self.inl[0].p.val_SI -
self.outl[0].p.val_SI)
k += 1
######################################################################
# equations for specified pressure ratio at hot side 2
if self.pr2.is_set:
self.residual[k] = (self.pr2.val * self.inl[1].p.val_SI -
self.outl[1].p.val_SI)
k += 1
######################################################################
# equations for specified pressure ratio at cold side
if self.pr3.is_set:
self.residual[k] = (self.pr3.val * self.inl[2].p.val_SI -
self.outl[2].p.val_SI)
k += 1
######################################################################
# equations for specified zeta at hot side 1
if self.zeta1.is_set:
self.residual[k] = self.zeta_func(zeta='zeta1',
inconn=0,
outconn=0)
k += 1
######################################################################
# equations for specified zeta at hot side 2
if self.zeta2.is_set:
self.residual[k] = self.zeta_func(zeta='zeta2',
inconn=1,
outconn=1)
k += 1
######################################################################
# equations for specified zeta at cold side
if self.zeta3.is_set:
self.residual[k] = self.zeta_func(zeta='zeta3',
inconn=2,
outconn=2)
k += 1
######################################################################
# equation for saturated liquid at hot side 1 outlet
if self.subcooling.val is False:
o1 = self.outl[0].to_flow()
self.residual[k] = o1[2] - h_mix_pQ(o1, 0)
k += 1
######################################################################
# equation for saturated gas at cold side outlet
if self.overheating.val is False:
o3 = self.outl[2].to_flow()
self.residual[k] = o3[2] - h_mix_pQ(o3, 1)
k += 1
def test_h_mix_pQ_on_mixtures():
with raises(ValueError):
h_mix_pQ([0, 0, 0, {'O2': 0.24, 'N2': 0.76}], 0.75)
