An advanced method for dilution zone mixing in a reverse flow gas turbine combustor was numerically investigated. For long mixing lengths associated with reverse flow combustors (X/H > 2.0), pattern factor was found to be mainly driven by nozzle-to-nozzle fuel flow and/or circumferential airflow variations; conventional radially injected dilution jets could not effectively mix out circumferential nonuniformities. To enhance circumferential mixing, dilution jets were angled to produce a high circumferential (swirl) velocity component. The jets on the outer liner were angled in one direction while the jets on the inner liner were angled in the opposite direction, thus enhancing turbulent shear at the expense of jet penetration. Three-dimensional CFD calculations were performed on a three-nozzle (90 deg) sector, with different fuel flow from each nozzle (90, 100, and 110 percent of design fuel flow). The computations showed that the optimum configuration of angled jets reduced the pattern factor by 60 percent compared to an existing conventional dilution hole configuration. The radial average temperature profile was adequately controlled by the inner-to-outer liner dilution flow split.

1.
Avva, R. K., Smith, C. E., and Singhal, A. K., 1990, “Comparative Study of High and Low Reynolds Number Versions of k-ε Models,” Paper No. AIAA-90-0246.
2.
Chen, Y. S., and Kim, S. W., 1987, “Computation of Turbulent Flows Using an Extended k-ε Turbulence Closure Model,” NASA CR-179204.
3.
Chien, K. Y., 1985, “Predictions of Channel and Boundary-Layer Flows With a Low-Reynolds-Number Turbulence Model,” AIAA Journal, Vol. 23, No. 2.
4.
Holdeman
J. D.
, and
Srinivasan
R.
,
1986
, “
Modeling Dilution Jet Flowfields
,”
Journal of Propulsion and Power
, Vol.
2
, No.
1
, pp.
4
10
.
5.
Holdeman, J. D., Reynolds, R., and White, C., 1987a, “A Numerical Study of the Effects of Curvature and Convergence on Dilution Jet Mixing,” Paper No. AIAA-87-1953.
6.
Holdeman
J. D.
,
Srinivasan
R.
,
Coleman
E. B.
,
Meyers
G. D.
, and
White
C. D.
,
1987
b, “
Effects of Multiple Rows and Noncircular Orifices on Dilution Jet Mixing
,”
Journal of Propulsion and Power
, Vol.
3
, No.
3
, pp.
219
226
.
7.
Holdeman, J. D., Srinivasan, R., and White, C. D., 1988, “An Empirical Model of the Effects of Curvature and Convergence on Dilution Jet Mixing,” Paper No. AIAA-88-3180.
8.
Holdeman, J. D., 1991, “Mixing of Multiple Jets With a Confined Subsonic Crossflow—Summary of NASA Supported Experiments and Modeling,” NASA TM-104412; Paper No. AIAA-91-2458.
9.
Kim, S. W., and Chen, C. P., 1988, “A Multiple Time Scale Turbulence Model Based on Variable Partitioning of Turbulence Kinetic Energy Spectrum,” Paper No. AIAA-88-1771.
10.
Launder
B. E.
, and
Spalding
D. B.
,
1974
, “
The Numerical Computation of Turbulent Flows
,”
Computer Methods in Applied Mechanics and Engineering
, Vol.
3
, pp.
269
289
.
11.
Owens, S. F., 1992, “CFD-ACE: Command Language Reference Manual,” CFD Research Corporation, Huntsville, AL, CFDRC Report GR-92-6.
12.
Reynolds, R., and White, C., 1986, “Transition Mixing Study Final Report,” NASA CR-175062.
13.
Smith, C. E., Ratcliff, M. L., Przekwas, A. J., and Habchi, S. D., 1989, “Validation of an Advanced Turbulent Combustion Code: REFLEQS,” presented at the 7th SSME CFD Workshop, NASA MSFC.
14.
Smith, C. E., 1990, “Mixing Characteristics of Dilution Jets in Small Gas Turbine Combustors,” Paper No. AIAA-90-2728.
15.
Srinivasan, R., Berenfeld, A., and Mongia, H. C., 1982, “Dilution Jet Mixing Program—Phase I Report,” NASA CR-168031.
16.
Srinivasan, R., Coleman, E., and Johnson, K., 1984, “Dilution Jet Mixing Program—Phase II Report,” NASA CR-174624.
17.
Srinivasan, R., Myers, G., Coleman, E., and White, C., 1985, “Dilution Jet Mixing Program—Phase III Report, NASA CR-174884.
This content is only available via PDF.
You do not currently have access to this content.