# -*- coding: utf-8
"""Module of class CombustionChamber.
This file is part of project TESPy (github.com/oemof/tespy). It's copyrighted
by the contributors recorded in the version control history of the file,
available from its original location
tespy/components/combustion/diabatic.py
SPDX-License-Identifier: MIT
"""
import numpy as np
from tespy.components import CombustionChamber
from tespy.tools import logger
from tespy.tools.data_containers import ComponentProperties as dc_cp
from tespy.tools.document_models import generate_latex_eq
from tespy.tools.fluid_properties import h_mix_pT
[docs]
class DiabaticCombustionChamber(CombustionChamber):
r"""
The class CombustionChamber is parent class of all combustion components.
**Mandatory Equations**
- :py:meth:`tespy.components.combustion.base.CombustionChamber.mass_flow_func`
- :py:meth:`tespy.components.combustion.base.CombustionChamber.combustion_pressure_func`
- :py:meth:`tespy.components.combustion.base.CombustionChamber.stoichiometry`
**Optional Equations**
- :py:meth:`tespy.components.combustion.base.CombustionChamber.lambda_func`
- :py:meth:`tespy.components.combustion.base.CombustionChamber.ti_func`
- :py:meth:`tespy.components.combustion.diabatic.DiabaticCombustionChamber.energy_balance_func`
- :py:meth:`tespy.components.combustion.diabatic.DiabaticCombustionChamber.pr_func`
Available fuels
- methane, ethane, propane, butane, hydrogen
Inlets/Outlets
- in1, in2
- out1
Image
.. image:: /api/_images/CombustionChamber.svg
:alt: flowsheet of the combustion chamber
:align: center
:class: only-light
.. image:: /api/_images/CombustionChamber_darkmode.svg
:alt: flowsheet of the combustion chamber
:align: center
:class: only-dark
.. note::
The fuel and the air components can be connected to either of the
inlets. The pressure of inlet 2 is disconnected from the pressure of
inlet 1. A warning is prompted, if the pressure at inlet 2 is lower than
the pressure at inlet 1.
Parameters
----------
label : str
The label of the component.
design : list
List containing design parameters (stated as String).
offdesign : list
List containing offdesign parameters (stated as String).
design_path : str
Path to the components design case.
local_offdesign : boolean
Treat this component in offdesign mode in a design calculation.
local_design : boolean
Treat this component in design mode in an offdesign calculation.
char_warnings : boolean
Ignore warnings on default characteristics usage for this component.
printout : boolean
Include this component in the network's results printout.
lamb : float, dict
Actual oxygen to stoichiometric oxygen ratio, :math:`\lambda/1`.
ti : float, dict
Thermal input, (:math:`{LHV \cdot \dot{m}_f}`), :math:`ti/\text{W}`.
eta : float, dict
Combustion thermal efficiency, :math:`\eta`. Heat loss calculation based
on share of thermal input.
pr : float, dict
Pressure ratio of outlet 1 to inlet 1, :math:`pr`.
Note
----
For more information on the usage of the combustion chamber see the
examples section on github or look for the combustion chamber tutorials
at tespy.readthedocs.io.
Example
-------
The combustion chamber calculates energy input due to combustion as well as
the flue gas composition based on the type of fuel and the amount of
oxygen supplied. In this example a mixture of methane, hydrogen and
carbondioxide is used as fuel.
>>> from tespy.components import Sink, Source, DiabaticCombustionChamber
>>> from tespy.connections import Connection
>>> from tespy.networks import Network
>>> from tespy.tools.fluid_properties import T_sat_p
>>> import shutil
>>> nw = Network(p_unit='bar', T_unit='C', iterinfo=False)
>>> amb = Source('ambient air')
>>> sf = Source('fuel')
>>> fg = Sink('flue gas outlet')
>>> comb = DiabaticCombustionChamber('combustion chamber')
>>> comb.component()
'diabatic combustion chamber'
>>> amb_comb = Connection(amb, 'out1', comb, 'in1')
>>> sf_comb = Connection(sf, 'out1', comb, 'in2')
>>> comb_fg = Connection(comb, 'out1', fg, 'in1')
>>> nw.add_conns(sf_comb, amb_comb, comb_fg)
Specify the thermal input of the combustion chamber. At the given fluid
compositions this determines the mass flow of the fuel. The outlet
temperature of the flue gas determines the ratio of oxygen to fuel mass
flow. In contrast to the simple combustion chamber, this component does
allow for a pressure drop. Therefore the outlet pressure or the pressure
ratio of the combustion chamber must be specified. Since the component is
not adiabatic, an efficiency value :code:`eta` can be supplied to account
for heat loss to the ambient. First, we specify :code:`eta=1` and expect
identical lambda or outlet temperature as in an adiabatic combustion
chamber.
>>> comb.set_attr(ti=500000, pr=0.95, eta=1, lamb=1.5)
>>> amb_comb.set_attr(p=1.2, T=20, fluid={'Ar': 0.0129, 'N2': 0.7553,
... 'CO2': 0.0004, 'O2': 0.2314})
>>> sf_comb.set_attr(T=25, fluid={'CO2': 0.03, 'H2': 0.01, 'CH4': 0.96}, p=1.3)
>>> nw.solve('design')
>>> comb_fg.set_attr(T=1200)
>>> comb.set_attr(lamb=None)
>>> nw.solve('design')
>>> round(comb.lamb.val, 3)
2.014
>>> round(comb_fg.p.val, 2)
1.14
Instead of the pressure ration, we can also specify the outlet pressure.
The pressure ratio is the ratio or pressure at the outlet to the pressure
at the inlet 1 (ambient air inlet in this example).
>>> comb.set_attr(pr=None)
>>> comb_fg.set_attr(p=1)
>>> nw.solve('design')
>>> round(comb.pr.val, 3)
0.833
We can change lambda to a specific value and unset the flue gas temperature:
>>> comb.set_attr(lamb=2)
>>> comb_fg.set_attr(T=None)
>>> nw.solve('design')
>>> round(comb_fg.T.val, 1)
1206.5
Now, if we change the efficiency value, e.g. to 0.9, a total of 10 % of
heat respective to the thermal input will be transferred to the ambient.
Note, that the heat loss :code:`Q_loss` has a negative value as it is
extracted from the system.
>>> eta = 0.9
>>> comb.set_attr(eta=eta)
>>> nw.solve('design')
>>> round(comb.Q_loss.val, 0)
-50000.0
>>> round(comb.ti.val * comb.eta.val, 0)
450000.0
"""
[docs]
@staticmethod
def component():
return 'diabatic combustion chamber'
[docs]
def get_parameters(self):
return {
'lamb': dc_cp(
min_val=1, deriv=self.lambda_deriv, func=self.lambda_func,
latex=self.lambda_func_doc, num_eq=1),
'ti': dc_cp(
min_val=0, deriv=self.ti_deriv, func=self.ti_func,
latex=self.ti_func_doc, num_eq=1),
'pr': dc_cp(
min_val=0, deriv=self.pr_deriv,
func=self.pr_func,
latex=self.pr_func_doc, num_eq=1),
'eta': dc_cp(
max_val=1, min_val=0, deriv=self.energy_balance_deriv,
func=self.energy_balance_func,
latex=self.energy_balance_func_doc, num_eq=1),
'Q_loss': dc_cp(max_val=0, is_result=True)
}
[docs]
def get_mandatory_constraints(self):
return {
k: v for k, v in super().get_mandatory_constraints().items()
if k in ["mass_flow_constraints", "stoichiometry_constraints"]
}
[docs]
def pr_func(self):
r"""
Equation for pressure drop.
Returns
-------
residual : float
Residual value of equation.
.. math::
0 = p_\mathrm{in,1} \cdot pr - p_\mathrm{out,1}
"""
return self.inl[0].p.val_SI * self.pr.val - self.outl[0].p.val_SI
[docs]
def pr_func_doc(self, label):
r"""
Equation for inlet pressure equality.
Parameters
----------
label : str
Label for equation.
Returns
-------
latex : str
LaTeX code of equations applied.
"""
latex = (
r'\begin{split}' + '\n'
r'0 = & p_\mathrm{in,1} \cdot pr - p_\mathrm{out,1}\\' + '\n'
r'\end{split}')
return generate_latex_eq(self, latex, label)
[docs]
def pr_deriv(self, increment_filter, k):
r"""
Calculate the partial derivatives for combustion pressure ratio.
Parameters
----------
increment_filter : ndarray
Matrix for filtering non-changing variables.
k : int
Position of equation in Jacobian matrix.
"""
i = self.inl[0]
o = self.outl[0]
if self.is_variable(i.p):
self.jacobian[k, i.p.J_col] = self.pr.val
if self.is_variable(o.p):
self.jacobian[k, o.p.J_col] = -1
[docs]
def energy_balance_func(self):
r"""
Calculate the energy balance of the diabatic combustion chamber.
Returns
-------
residual : float
Residual value of equation.
.. math::
\begin{split}
0 = & \sum_i \dot{m}_{in,i} \cdot
\left( h_{in,i} - h_{in,i,ref} \right)\\
& -\dot{m}_{out,2}\cdot\left( h_{out,1}-h_{out,1,ref} \right)\\
& + LHV_{fuel} \cdot\left(\sum_i\dot{m}_{in,i}\cdot
x_{fuel,in,i}- \dot{m}_{out,1} \cdot x_{fuel} \right)
\cdot \eta
\end{split}\\
\forall i \in \text{inlets}
Note
----
The temperature for the reference state is set to 25 °C, thus
the water may be liquid. In order to make sure, the state is
referring to the lower heating value, the state of the water in the
flue gas is fored to gaseous.
- Reference temperature: 298.15 K.
- Reference pressure: 1 bar.
"""
T_ref = 298.15
p_ref = 1e5
res = 0
for i in self.inl:
i.build_fluid_data()
res += i.m.val_SI * (
i.h.val_SI
- h_mix_pT(p_ref, T_ref, i.fluid_data, mixing_rule="forced-gas")
)
for o in self.outl:
o.build_fluid_data()
res -= o.m.val_SI * (
o.h.val_SI
- h_mix_pT(p_ref, T_ref, o.fluid_data, mixing_rule="forced-gas")
)
res += self.calc_ti() * self.eta.val
return res
[docs]
def energy_balance_func_doc(self, label):
r"""
Calculate the energy balance of the diabatic combustion chamber.
Parameters
----------
label : str
Label for equation.
Returns
-------
latex : str
LaTeX code of equations applied.
"""
latex = (
r'\begin{split}' + '\n'
r'0 = & \sum_i \dot{m}_{\mathrm{in,}i} \cdot\left( '
r'h_{\mathrm{in,}i} - h_{\mathrm{in,}i\mathrm{,ref}} \right) -'
r'\dot{m}_\mathrm{out,1}\cdot\left( h_\mathrm{out,1}'
r' - h_\mathrm{out,1,ref}\right)\\' + '\n'
r'& + LHV_{fuel} \cdot \left(\sum_i \dot{m}_{\mathrm{in,}i} '
r'\cdot x_{fuel\mathrm{,in,}i} - \dot{m}_\mathrm{out,1} '
r'\cdot x_{fuel\mathrm{,out,1}} \right) \cdot \eta\\' + '\n'
r'& \forall i \in \text{inlets}\\'
r'& T_\mathrm{ref}=\unit[298.15]{K}'
r'\;p_\mathrm{ref}=\unit[10^5]{Pa}\\'
'\n' + r'\end{split}'
)
return generate_latex_eq(self, latex, label)
[docs]
def calc_parameters(self):
r"""Postprocessing parameter calculation."""
super().calc_parameters()
T_ref = 298.15
p_ref = 1e5
res = 0
for i in self.inl:
i.build_fluid_data()
res += i.m.val_SI * (
i.h.val_SI
- h_mix_pT(p_ref, T_ref, i.fluid_data, mixing_rule="forced-gas")
)
for o in self.outl:
o.build_fluid_data()
res -= o.m.val_SI * (
o.h.val_SI
- h_mix_pT(p_ref, T_ref, o.fluid_data, mixing_rule="forced-gas")
)
self.eta.val = -res / self.ti.val
self.Q_loss.val = -(1 - self.eta.val) * self.ti.val
self.pr.val = self.outl[0].p.val_SI / self.inl[0].p.val_SI
for num, i in enumerate(self.inl):
if i.p.val < self.outl[0].p.val:
msg = (
f"The pressure at inlet {num + 1} is lower than the "
f"pressure at the outlet of component {self.label}."
)
logger.warning(msg)
[docs]
def exergy_balance(self, T0):
self.E_P = self.outl[0].Ex_physical - (
self.inl[0].Ex_physical + self.inl[1].Ex_physical
)
self.E_F = (
self.inl[0].Ex_chemical + self.inl[1].Ex_chemical -
self.outl[0].Ex_chemical
)
self.E_D = self.E_F - self.E_P
self.epsilon = self._calc_epsilon()
self.E_bus = {"chemical": np.nan, "physical": np.nan, "massless": np.nan}