134
V. Kirubakaran and D. S. Bhatt
4.1 Grid-Independent Study
The unstructured grid has been employed due to the complexity of combustor geometry. The grid-independent study is carried out for four different grid sizes. The
mass-weighted average of differential pressure is compared with Grid-D. The results
were obtained numerically at 10.19 m/s inlet velocity. As can be seen from Table 1,
almost similar results were obtained with the Grid-B and Grid-C. When grid size is
increased further as in Grid-D, small difference is observed.
Alternately, the center line velocity across the combustor length for different
grids (Fig. 4) is also considered. From the plot, it can be seen that the velocity profile
matches closely for all grids considered. Hence, considering the optimality, Grid-B
is adopted in the study.
5 Results and Discussion
The flow field inside an can combustor has been analyzed for a 90° sector model under
non-reacting flow conditions. Expect flame tube wall thickness, the other blockages
in geometry like snout wall, swirler wall, and fuel injector were included in this
analysis. The performance characteristics of the combustor for non-reacting flow
Table 1 Grid study for four different grid sizes for 10.19 m/s inlet velocity case
Description
Grid type
Elements
Differential pressure [Pa]
Difference [%]
Grid-A
Tetrahedral
2,018,026
51.90
4
Grid-B
Tetrahedral
2,687,636
48.81
2
Grid-C
Tetrahedral
4,009,738
48.37
2
Grid-D
Tetrahedral
5,942,049
46.03
–
Fig. 4 Combustor center line velocity variation for 10.19 m/s inlet velocity
V. Kirubakaran and D. S. Bhatt
4.1 Grid-Independent Study
The unstructured grid has been employed due to the complexity of combustor geometry. The grid-independent study is carried out for four different grid sizes. The
mass-weighted average of differential pressure is compared with Grid-D. The results
were obtained numerically at 10.19 m/s inlet velocity. As can be seen from Table 1,
almost similar results were obtained with the Grid-B and Grid-C. When grid size is
increased further as in Grid-D, small difference is observed.
Alternately, the center line velocity across the combustor length for different
grids (Fig. 4) is also considered. From the plot, it can be seen that the velocity profile
matches closely for all grids considered. Hence, considering the optimality, Grid-B
is adopted in the study.
5 Results and Discussion
The flow field inside an can combustor has been analyzed for a 90° sector model under
non-reacting flow conditions. Expect flame tube wall thickness, the other blockages
in geometry like snout wall, swirler wall, and fuel injector were included in this
analysis. The performance characteristics of the combustor for non-reacting flow
Table 1 Grid study for four different grid sizes for 10.19 m/s inlet velocity case
Description
Grid type
Elements
Differential pressure [Pa]
Difference [%]
Grid-A
Tetrahedral
2,018,026
51.90
4
Grid-B
Tetrahedral
2,687,636
48.81
2
Grid-C
Tetrahedral
4,009,738
48.37
2
Grid-D
Tetrahedral
5,942,049
46.03
–
Fig. 4 Combustor center line velocity variation for 10.19 m/s inlet velocity