docs: Update solver and meshing in examples [skip tests] (#4110)

closes #4091

Rename solver and meshing to solver_session and meshing_session
respectively.

Corrected `set_units` command in CHT example.

---------

Co-authored-by: pyansys-ci-bot <[email protected]>

Author: hpohekar

doc/changelog.d/4110.documentation.md

@@ -0,0 +1 @@
+Update solver and meshing in examples [skip tests]

examples/00-fluent/DOE_ML.py

@@ -86,19 +86,19 @@
 # Launch Fluent session with solver mode and print Fluent version
 # ===============================================================
 
-solver = pyfluent.launch_fluent(
+solver_session = pyfluent.launch_fluent(
     precision="double",
     processor_count=2,
     version="3d",
 )
-print(solver.get_fluent_version())
+print(solver_session.get_fluent_version())
 
 
 #############################################################################
 # Read case
 # =========
 
-solver.settings.file.read_case(file_name=import_filename)
+solver_session.settings.file.read_case(file_name=import_filename)
 
 ##############################################################################################
 # Design of Experiments
@@ -113,21 +113,21 @@
 
 for idx1, coldVel in np.ndenumerate(coldVelArr):
     for idx2, hotVel in np.ndenumerate(hotVelArr):
-        cold_inlet = solver.settings.setup.boundary_conditions.velocity_inlet[
+        cold_inlet = solver_session.settings.setup.boundary_conditions.velocity_inlet[
             "cold-inlet"
         ]
         cold_inlet.momentum.velocity.value = coldVel
 
-        hot_inlet = solver.settings.setup.boundary_conditions.velocity_inlet[
+        hot_inlet = solver_session.settings.setup.boundary_conditions.velocity_inlet[
             "hot-inlet"
         ]
         hot_inlet.momentum.velocity.value = hotVel
 
-        solver.settings.solution.initialization.initialization_type = "standard"
-        solver.settings.solution.initialization.standard_initialize()
-        solver.settings.solution.run_calculation.iterate(iter_count=200)
+        solver_session.settings.solution.initialization.initialization_type = "standard"
+        solver_session.settings.solution.initialization.standard_initialize()
+        solver_session.settings.solution.run_calculation.iterate(iter_count=200)
 
-        res_tui = solver.scheme.exec(
+        res_tui = solver_session.scheme.exec(
             (
                 "(ti-menu-load-string "
                 '"/report/surface-integrals/mass-weighted-avg outlet () '
@@ -141,7 +141,7 @@
 # Close the session
 # =================
 
-solver.exit()
+solver_session.exit()
 
 ####################################
 # Plot Response Surface using Plotly