You signed in with another tab or window. Reload to refresh your session.You signed out in another tab or window. Reload to refresh your session.You switched accounts on another tab or window. Reload to refresh your session.Dismiss alert
is iterated until the temperature difference $T_b - T(\mathcal{y},h_i,Z)$ is less than $1e-3K$.
326
326
327
-
For the current example, the equivalence ratio at the inlet was set to 0.5, translating to a mixture fraction of 1.447e-2. The reactants are presumed at a temperature of 300K at the inlet, while isothermal wall boundary conditions (400K) are applied on the burner wall and heat exchanger emulator. The iso-thermal wall boundary conditions are defined as weak boundary conditions.
327
+
For the current example, the equivalence ratio at the inlet was set to 0.5, translating to a mixture fraction of 1.447e-2. The reactants are presumed at a temperature of 300K at the inlet, while isothermal wall boundary conditions are applied on the burner wall (350K) and heat exchanger emulator (400K). The iso-thermal wall boundary conditions are defined as strong boundary conditions, meaning that the total enthalpy is locally enforced to achieve the imposed temperature.
Just like for regular species transport problems, there are two options available for the `CONV_NUM_METHOD_SPECIES`, those being `SCALAR_UPWIND` and `BOUNDED_SCALAR`.
@@ -354,11 +355,26 @@ The current section describes the hydrogen burner tutorial in more detail.
354
355
355
356
## Manifold set-up
356
357
357
-
In the current tutorial, a set of MLP's is used for the manifold. These MLP's are visualized below:
358
+
In the current tutorial, a set of MLP's is used for the manifold. These MLP's are visualized below.
These MLP's were trained on flamelet data consisting of adiabatic free-flame data, burner-stabilized data, and chemical equilibrium data obtained over a range of equivalence ratio's and reactant temperature of 0.3-6.0 and 300K-900K respectively.
All networks use the Gaussian Error Linear Unit (GELU) activation function for all hidden layers and were trained on flamelet data consisting of adiabatic free-flame data, burner-stabilized data, and chemical equilibrium data obtained over a range of equivalence ratio's and reactant temperature of 0.3-6.0 and 280K-900K respectively.
The case converges nicely as expected on such a simple case and mesh.
416
+
After 3000 iterations, the simulation converges to the following solution. This solution should not be taken as a fully accurate representation of the current problem, as neither the mesh nor manifold were optimized for the current application.
417
+
418
+
The following image shows the solution for the progress variable and total enthalpy side-by-side. The progress variable solution indicates the progress of the reaction, with a local maximum next to the flame front, as is the case for lean, pre-mixed flames with preferential diffusion and no stretch. The total enthalpy solution correctly shows decreases near the cooled surfaces.
The solution for the mixture fraction and NO species is shown in the next figure. Due to the effects of preferential diffusion, the mixture fraction solution shows a local minimum in regions of positive flame curvature. The NO solution contains a local maximum in the region of maximum temperature and remaining nearly constant afterwards due to the reduction in temperature from the heat exchanger emulator.
Finally, the results for the temperature and heat release rate are shown below. These quantities are not retrieved through solving transport equations, but by retrieving them from the flamelet manifold.
An in depth optimization of this case with addition of the FFD-box, gradient validation and some more steps can found [here](/tutorials/Species_Transport/).
0 commit comments