A novel fuel-air mixing technique on the basis of vortex generators has been developed and successfully implemented in the worlds first lean-premix reheat combustor of ABB’s GT24/GT26 series industrial gas turbines. This technique uses a special arrangement of delta-wing type vortex generators to achieve rapid mixing through longitudinal vortices, which produce low pressure drop and no recirculation zones along the mixing section. In this paper, after a short introduction to the topic, the motivation for utilizing vortex generators and the main considerations in their design are explained. A detailed analysis of the flow field, pressure drop and the strength of the vortices generated by a single vortex generator are presented as one of the three main geometrical parameters is varied. The results obtained through water model tests indicate that an optimum vortex generator geometry exists, which produces the maximum circulation at a relatively low pressure drop price. Moreover, the axial velocity distribution along the mixing section stays uniform enough to assure flash-back free operation despite the elevated inlet temperatures encountered in a reheat combustor. After selecting this optimized geometry, the process of the arrangement of multiple vortex generators in an annular combustor segment is described. The optimum arrangement presented here is suitable both for gaseous and liquid fuel injection, since it requires only one injection location per combustor segment.

1.
Frutschi
,
H. U.
,
1994
, “
Advanced Cycle System With New GT24/GT26 Turbines—Historical Background
,”
ABB Rev.
,
1
, pp.
21
25
.
2.
Sattelmayer, T., Felchlin, M., Haumann, J., Hellat, J., and Steyner, D., 1990, “Second Generation Low Emission Combustors for ABB Gas Turbines: Burner Development and Tests at Atmospheric Pressure,” ASME Paper 90-GT-162.
3.
Aigner, M., Mayer, A., Schiessel, P., and Strittmatter W., 1990, “Second Generation Low Emission Combustors for ABB Gas Turbines: Tests Under Full Engine Conditions,” ASME Paper 90-GT-308.
4.
Senior, P., Luturm, E., Polifke, W., and Sattelmayer, T., 1993, “Combustion Technology of the ABB GT13E2 Annular Combustor,” 20th CIMAC G22 1993, London.
5.
Joos, F., Brunner, P., Schulte-Werning, B., Syed, K., and Eroglu, A., 1996, “Development of the Sequential Combustion System for the ABB GT24/GT26 Gas Turbine Family,” ASME Paper 96-GT-315.
6.
Kuethe, A. M., and Chow, C.-Y., 1986, Foundations of Aerodynamics, John Wiley and Sons, New York.
You do not currently have access to this content.