=============
Axial turbine
=============

:download:`Download this example <../../examples/axial_turbine.yaml>`

Input file
==========


.. code-block:: yaml

   # Axial turbine
   #
   # A repeating-stage axial turbine with two blade rows.

   # New working directory for each invocation
   workdir: runs/*

   # Perfect gas inlet reprensentative of a gas turbine
   inlet:
     Po: 16.0e5
     To: 1600.
     cp: 1100.
     gamma: 1.33

   # Set viscosity by vane Reynolds number
   Re_surf: 4e5

   # Design variables for an axial turbine
   mean_line:
     type: axial_turbine
     # Duty
     mdot: 500.
     rrms: 1.0
     # Aerodynamics
     psi: 1.6
     phi2: 0.6
     Ma2: 0.7
     fac_Ma3_rel: 1.0
     zeta: [1.0, 1.0]
     # Guess of loss
     Ys: [0.02, 0.05]

   # Prescribe the dimensional chords
   annulus:
     type: fixed_axial_chord
     cx_gap: [0.1, 0.06, 0.1]
     cx_row: [0.1, 0.1]

   # Coarse H-mesh
   mesh:
     type: h
     yplus: 30.0
     resolution_factor: 0.5

   # Define one mid-span section in stator and rotor
   blades:
       - spf: 0.5
         q_thick: [0.05, 0.12, 0.3, 0.2, 0.0, 0.1]
         q_camber: [0., 4., 0.0]
       - spf: 0.5
         q_thick: [0.05, 0.12, 0.3, 0.2, 0.0, 0.1]
         q_camber: [0., 5., 0.0]
         tip: 0.01

   # Circulation coefficient to set blade loadings
   nblade:
     - Co: 0.6
     - Co: 0.6

   # Configure the RANS solver
   solver:
     type: emb
     n_step: 2000
     n_step_avg: 100
     n_step_ramp: 1000

   # Configure iterative updates of the geometry
   iterate:
     # Make the mean-line loss match CFD
     mean_line:
       tolerance:
         Ys: 0.01
     # Correct for deviation using trailing-edge recamber
     deviation:
     # Correct for incidence using leading-edge recamber
     incidence:
     # Copy spanwise profiles at outlet to the inlet
     # to model a repeating stage
     repeat:

   # Additional plots to produce
   post_process:
     # Loss at stator and rotor exits
     # Non-dimensional meridional coordinate m is defined:
     #   m=0 at inlet
     #   m=1 at stator LE
     #   m=2 at stator TE,
     #   m=3 at rotor LE
     #   m=4 at rotor TE
     #   m=5 at exit
     - type: contour
       coord: m
       value: [2.05, 4.05]
       variable: Ys
     # Mid-span Mach
     - type: contour
       coord: spf
       value: 0.5
       variable: Ma_rel

Log output
==========

.. code-block:: none

    *** TURBIGEN v2.1.0 ***
    Starting at 2025-04-23T11:45:31
    Working directory: /builds/jb753/turbigen/runs/0000
    Iterating for max 10 iterations...
    Convergence status:
      deviation: False
      incidence: False
      mean_line: False
      repeat: False
      Min Dev[0] DDev[0] Dev[1] DDev[1] Inc[0] DInc[0] Inc[1] DInc[1] Ys[0] DYs[0] Ys[1] DYs[1] Repeat_dTo
    ------------------------------------------------------------------------------------------------------
     1.76   4.07      -2   6.36      -2   -122      -2    132       2 0.039  0.015 0.078  0.023      0.017
     1.93   1.88   -1.88   4.17      -2  -18.9   -0.94   30.7    1.54 0.035  0.000 0.078  0.004      0.004
     1.86  -0.09   0.098   2.05      -2   7.56   0.378   -5.9   -0.29  0.03  -0.00 0.072  -0.00      0.007
     1.87  -0.10   0.102  -0.15   0.154  -2.95   -0.14  -15.6   -0.77 0.027  -0.00 0.070  -0.00      0.006
     1.87  -0.00   0.000  -0.10   0.103  -2.06   -0.10  -2.71   -0.13 0.029  0.000 0.071  0.000      0.001
    Convergence status:
      deviation: True
      incidence: True
      mean_line: True
      repeat: False
      Min Dev[0] DDev[0] Dev[1] DDev[1] Inc[0] DInc[0] Inc[1] DInc[1] Ys[0] DYs[0] Ys[1] DYs[1] Repeat_dTo
    ------------------------------------------------------------------------------------------------------
     1.88  -0.01   0.016  0.006   -0.00  -1.52   -0.07  -1.87   -0.09 0.029  0.000 0.071  0.000      0.001
      1.9  -0.01   0.011  -0.00   0.009  -1.16   -0.05  -1.19   -0.05  0.03  0.000 0.072  0.000      0.000
    Finished iterating, converged=True.
       Variable  Nominal  Actual   Err_abs  Err_rel/%
    -------------------------------------------------
            Ma2      0.7   0.696     0.004      0.571
          Ys[0]     0.03    0.03  -7.8e-05      -0.26
          Ys[1]   0.0719   0.072  -6.3e-05     -0.088
    fac_Ma3_rel        1       1  -0.00487     -0.487
           mdot      500     500     0.168     0.0337
           phi2      0.6   0.599   0.00119      0.198
            psi      1.6    1.59   0.00547      0.342
           rrms        1       1         0          0
        zeta[0]        1       1  -0.00049     -0.049
        zeta[1]        1       1   -0.0037      -0.37
          PR_tt              1.7                     
        Ma3_rel            0.701                     
         Alpha1            -24.8                     
            Lam            0.522                     
           htr2            0.875                     
    Efficiency/%: eta_tt=91.5, eta_ts=81.4

Plots
=====

.. image:: axial_turbine.yaml_post_1.svg
   :width: 100%

.. image:: axial_turbine.yaml_post_2.svg
   :width: 100%

.. image:: axial_turbine.yaml_post_3.svg
   :width: 100%

.. image:: axial_turbine.yaml_post_4.svg
   :width: 100%

.. image:: axial_turbine.yaml_post_5.svg
   :width: 100%

.. image:: axial_turbine.yaml_post_6.svg
   :width: 100%

.. image:: axial_turbine.yaml_post_7.svg
   :width: 100%

.. image:: axial_turbine.yaml_post_8.svg
   :width: 100%