implement "pathllib"

replace os.path ... with Path ... in examples, __init__.py, utilities.py, and chemkin_wrapper.py

Author: cpchou23

examples/PFR/plugflow.py

@@ -20,7 +20,7 @@
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 # SOFTWARE.
 
-""".. _ref_plug_flow_reactor:
+r""".. _ref_plug_flow_reactor:
 
 ===========================================
 Simulate NO reduction in combustion exhaust
@@ -31,25 +31,29 @@
 as well as its resemblance of an exhaust duct or a tailpipe.
 
 The PFR model is a steady-state open reactor because materials are allowed to
-move in and out of the reactor. The solutions are obtained along the length of the reactor
-as the inlet materials march toward the reactor exit. Typically, the pressure of the PFR
-is fixed. However, Chemkin does permit the use of a pressure profile to enforce a certain
-pressure gradient in the PFR.
-
-Use the ``PlugFlowReactor_FixedTemperature()`` or ``PlugFlowReactor_EnergyConservation()``
-method to create a PFR. Unlike the closed batch reactor model, which is instantiated by a mixture,
+move in and out of the reactor. The solutions are obtained along the length of
+the reactor as the inlet materials march toward the reactor exit. Typically,
+the pressure of the PFR is fixed. However, Chemkin does permit the use of
+a pressure profile to enforce a certain pressure gradient in the PFR.
+
+Use the ``PlugFlowReactor_FixedTemperature()`` or
+``PlugFlowReactor_EnergyConservation()`` method to create a PFR.
+Unlike the closed batch reactor model, which is instantiated by a mixture,
 the open reactor model, such as the PFR model, is initiated by a stream, which is
 simply a mixture with the addition of the inlet mass/volumetric
-flow rate or velocity. You already know how to create a stream if you know how to create
-a mixture. You can specify the inlet flow rate using one of these methods:
+flow rate or velocity. You already know how to create a stream if you know
+how to create a mixture. You can specify the inlet flow rate using one of
+these methods:
 ``velocity()``, ``mass_flowrate()``, ``vol_flowrate()``, or ``sccm()``
 (standard cubic centimeters per minute).
 
 This example shows how to use the Chemkin PFR model to study the
 reduction of nitric oxide (NO) in the combustion exhaust by using the
-CH\ :sub:`4` reburning process. This is achieved by injecting CH\ :sub:`4` into the
-hot exhaust gas mixture. As the exhaust gas travels along the tubular reactor, the injected
-CH\ :sub:`4` is oxidized by the NO to form N\ :sub:`2`\ , CO, and H\ :sub:`2`. This is why this NO reduction process is called *methane reburning*.
+CH\ :sub:`4` reburning process. This is achieved by injecting CH\ :sub:`4` into
+the hot exhaust gas mixture. As the exhaust gas travels along the tubular reactor,
+the injected CH\ :sub:`4` is oxidized by the NO to form
+N\ :sub:`2`\ , CO, and H\ :sub:`2`. This is why this NO reduction process is called
+*methane reburning*.
 """
 
 # sphinx_gallery_thumbnail_path = '_static/plot_plug_flow_reactor.png'
@@ -58,7 +62,7 @@
 # Import PyChemkin packages and start the logger
 # ==============================================
 
-import os
+from pathlib import Path
 import time
 
 import matplotlib.pyplot as plt  # plotting
@@ -73,7 +77,7 @@
 from ansys.chemkin.core.logger import logger
 
 # check working directory
-current_dir = os.getcwd()
+current_dir = str(Path.cwd())
 logger.debug("working directory: " + current_dir)
 # set interactive mode for plotting the results
 # interactive = True: display plot
@@ -84,18 +88,18 @@
 ########################
 # Create a chemistry set
 # ======================
-# The mechanism to load is the C2 NOx mechanism for the combustion of C1-C2 hydrocarbons.
-# The mechanism comes with the standard Ansys Chemkin
+# The mechanism to load is the C2 NOx mechanism for the combustion o
+#  C1-C2 hydrocarbons. The mechanism comes with the standard Ansys Chemkin
 # installation in the ``/reaction/data`` directory.
 
 # set mechanism directory (the default Chemkin mechanism data directory)
-data_dir = os.path.join(ck.ansys_dir, "reaction", "data")
+data_dir = Path(ck.ansys_dir) / "reaction" / "data"
 mechanism_dir = data_dir
 # create a chemistry set based on the GRI mechanism
 MyGasMech = ck.Chemistry(label="C2 NOx")
 # set mechanism input files
 # including the full file path is recommended
-MyGasMech.chemfile = os.path.join(mechanism_dir, "C2_NOx_SRK.inp")
+MyGasMech.chemfile = str(mechanism_dir / "C2_NOx_SRK.inp")
 
 ######################################
 # Preprocess the GRI 3.0 chemistry set
@@ -109,10 +113,10 @@
 # =================================
 # Create a hot exhaust gas mixture by assigning the mole fractions of the
 # species. A stream is simply a mixture with the addition of
-# mass/volumetric flow rate or velocity. Here, the gas composition ``exhaust.X`` is given
-# by a recipe consisting of the common species in the combustion exhaust, such as
-# CO\ :sub:`2` and H\ :sub:`2`O and the CH\ :sub:`4` injected. The inlet velocity
-# is given by ``exhaust.velocity = 26.815``.
+# mass/volumetric flow rate or velocity. Here, the gas composition ``exhaust.X``
+# is given by a recipe consisting of the common species in the combustion exhaust,
+# such as CO\ :sub:`2` and H\ :sub:`2`O and the CH\ :sub:`4` injected.
+# The inlet velocity is given by ``exhaust.velocity = 26.815``.
 
 # create the inlet (mixture + flow rate)
 exhaust = Stream(MyGasMech)
@@ -136,20 +140,20 @@
 #####################################
 # Create the plug flow reactor object
 # ===================================
-# Use the ``PlugFlowReactor_FixedTemperature()`` method to create a plug flow reactor.
-# The required input parameter of the open reactor models in PyChemkin
-# is the stream, while PyChemkin batch reactor models take a mixture
-# as the input parameter. In this case, the exhaust stream is used to create a
-# PFR named ``tubereactor``.
+# Use the ``PlugFlowReactor_FixedTemperature()`` method to create
+# a plug flow reactor. The required input parameter of
+# the open reactor models in PyChemkin is the stream, while PyChemkin
+# batch reactor models take a mixture as the input parameter. In this case,
+# the exhaust stream is used to create a PFR named ``tubereactor``.
 tubereactor = PlugFlowReactor_FixedTemperature(exhaust)
 
 ############################################
 # Set up additional reactor model parameters
 # ==========================================
-# For the PFR, the required reactor parameters are the reactor diameter [cm] or the
-# cross-sectional flow area [cm2] and the reactor length [cm].
-# The mixture condition and inlet mass flow rate of the inlet are already defined
-# by the stream when the ``tubereactor`` PFR is instantiated.
+# For the PFR, the required reactor parameters are the reactor diameter [cm]
+# or the cross-sectional flow area [cm2] and the reactor length [cm].
+# The mixture condition and inlet mass flow rate of the inlet are already
+# defined by the stream when the ``tubereactor`` PFR is instantiated.
 
 # set PFR diameter [cm]
 tubereactor.diameter = 5.8431
@@ -168,13 +172,14 @@
 ####################
 # Set output options
 # ==================
-# You can turn on adaptive solution saving to resolve the steep variations in the solution
-# profile. Here, additional solution data points are saved for every **100** internal solver steps.
+# You can turn on adaptive solution saving to resolve the steep variations
+# in the solution profile. Here, additional solution data points are saved
+# for every **100** internal solver steps.
 #
 # .. note::
-#   By default, distance intervals for both print and save solution are 1/100 of the
-#   reactor length. In this case, :math:`dt=time/100=0.001`\ . You can change them
-#   to different values.
+#   By default, distance intervals for both print and save solution are
+#   1/100 of the reactor length. In this case, :math:`dt=time/100=0.001`\ .
+#   You can change them to different values.
 
 # set distance between saving solution
 tubereactor.timestep_for_saving_solution = 0.0005
@@ -219,19 +224,22 @@
 # The postprocessing step parses the solution and packages the solution values at each
 # time point into a mixture. There are two ways to access the solution profiles:
 #
-# - The raw solution profiles (value as a function of distance) are available for distance,
-#   temperature, pressure, volume, and species mass fractions.
+# - The raw solution profiles (value as a function of distance) are available
+#   for distance, temperature, pressure, volume, and species mass fractions.
 #
 # - The mixtures permit the use of all property and rate utilities to extract
 #   information such as viscosity, density, and mole fractions.
 #
-# You can use the ``get_solution_variable_profile()`` method to get the raw solution profiles. You
-# can get solution mixtures using either the ``get_solution_mixture_at_index()`` method for the
-# solution mixture at the given saved location or the ``get_solution_mixture()`` method for the
-# solution mixture at the given distance. (In this case, the mixture is constructed by interpolation.)
+# You can use the ``get_solution_variable_profile()`` method to get
+# the raw solution profiles. You can get solution mixtures using either the
+# ``get_solution_mixture_at_index()`` method for the solution mixture at
+# the given saved location or the ``get_solution_mixture()`` method for the
+# solution mixture at the given distance.
+# (In this case, the mixture is constructed by interpolation.)
 #
-# You can get the outlet solution by simply grabbing the solution values at the very last point by
-# using \ :math:`(outlet solution index) = (number of solutions) - 1`\.
+# You can get the outlet solution by simply grabbing the solution values
+# at the very last point by using
+# \ :math:`(outlet solution index) = (number of solutions) - 1`\.
 #
 
 # postprocess the solution profiles
@@ -246,29 +254,29 @@
 # get the temperature profile [K]
 tempprofile = tubereactor.get_solution_variable_profile("temperature")
 # get the CH4 mass fraction profile
-YCH4profile = tubereactor.get_solution_variable_profile("CH4")
+ch4_y_profile = tubereactor.get_solution_variable_profile("CH4")
 # get the CO mass fraction profile
-YCOprofile = tubereactor.get_solution_variable_profile("CO")
+co_y_profile = tubereactor.get_solution_variable_profile("CO")
 # get the H2O mass fraction profile
-YH2Oprofile = tubereactor.get_solution_variable_profile("H2O")
+h2o_y_profile = tubereactor.get_solution_variable_profile("H2O")
 # get the H2 mass fraction profile
-YH2profile = tubereactor.get_solution_variable_profile("H2")
+h2_y_profile = tubereactor.get_solution_variable_profile("H2")
 # get the NO mass fraction profile
-YNOprofile = tubereactor.get_solution_variable_profile("NO")
+no_y_profile = tubereactor.get_solution_variable_profile("NO")
 # get the N2 mass fraction profile
-YN2profile = tubereactor.get_solution_variable_profile("N2")
+n2_y_profile = tubereactor.get_solution_variable_profile("N2")
 
 # inlet NO mass fraction
-YNO_inlet = exhaust.Y[MyGasMech.get_specindex("NO")]
+no_y_inlet = exhaust.Y[MyGasMech.get_specindex("NO")]
 # outlet grid index
 xout_index = solutionpoints - 1
 print("At the reactor inlet: x = 0 [xm]")
-print(f"The NO mass fraction = {YNO_inlet}.")
+print(f"The NO mass fraction = {no_y_inlet}.")
 print(f"At the reactor outlet: x = {xprofile[xout_index]} [cm]")
-print(f"The NO mass fraction = {YNOprofile[xout_index]}.")
+print(f"The NO mass fraction = {no_y_profile[xout_index]}.")
 print(
     "The NO conversion rate = "
-    + f"{(YNO_inlet - YNOprofile[xout_index]) / YNO_inlet * 100.0} %\n."
+    + f"{(no_y_inlet - no_y_profile[xout_index]) / no_y_inlet * 100.0} %\n."
 )
 
 # more involved postprocessing using mixtures
@@ -297,22 +305,23 @@
 # Plot the species and the gas velocity profiles along the tubular reactor.
 #
 # You can see from the plots that CH\ :sub:`4` is mainly oxidized by NO to form
-# N\ :sub:`2` and H\ :sub:`2`\ in the hot exhaust. The gas velocity accelerates because of
-# the net increase in total number of moles of gas species due to the chemical reactions.
-# You can conduct more in depth analyses of the reaction pathways of the CH\ :sub:`4` reburning
-# mechanism by applying other PyChemkin utilities.
+# N\ :sub:`2` and H\ :sub:`2`\ in the hot exhaust. The gas velocity accelerates
+# because of the net increase in total number of moles of gas species due to
+# the chemical reactions. You can conduct more in depth analyses of
+# the reaction pathways of the CH\ :sub:`4` reburning mechanism by
+# applying other PyChemkin utilities.
 plt.subplots(2, 2, sharex="col", figsize=(12, 6))
 plt.suptitle("Constant Temperature Plug-Flow Reactor", fontsize=16)
 plt.subplot(221)
-plt.plot(xprofile, YN2profile, "r-")
+plt.plot(xprofile, n2_y_profile, "r-")
 plt.ylabel("N2 Mass Fraction")
 plt.subplot(222)
-plt.plot(xprofile, YH2Oprofile, "b-", label="H2O")
+plt.plot(xprofile, h2o_y_profile, "b-", label="H2O")
 plt.ylabel("H2O Mass Fraction")
 plt.subplot(223)
-plt.plot(xprofile, YNOprofile, "g-", label="NO")
-plt.plot(xprofile, YCH4profile, "g:", label="CH4")
-plt.plot(xprofile, YH2profile, "g--", label="H2")
+plt.plot(xprofile, no_y_profile, "g-", label="NO")
+plt.plot(xprofile, ch4_y_profile, "g:", label="CH4")
+plt.plot(xprofile, h2_y_profile, "g--", label="H2")
 plt.legend()
 plt.xlabel("distance [cm]")
 plt.ylabel("Mass Fraction")