Computational sensitivity study of spray dispersion and mixing on the fuel properties in a gas turbine combustor. (2nd February 2017)

• Record Type: Journal Article
• Authors: Grosshans, Holger; Cao, Le; Fuchs, Laszlo; Szász, Robert-Zoltán
• Is Part Of: Fluid dynamics research. Volume 49:Number 2(2017:Apr.)
• Publication Date: 2017-02-02
• Subjects: fuel spray -- large eddy simulation -- gas turbine burner -- Eulerian–Lagrangian; Fluid dynamics -- Periodicals; 620.106
• DOI: 10.1088/1873-7005/49/2/025506
• Languages: English
• ISSNs: 0169-5983

Abstract

Abstract: A swirl stabilized gas turbine burner has been simulated in order to assess the effects of the fuel properties on spray dispersion and fuel–air mixing. The properties under consideration include fuel surface tension, viscosity and density. The turbulence of the gas phase is modeled applying the methodology of large eddy simulation whereas the dispersed liquid phase is described by Lagrangian particle tracking. The exchange of mass, momentum and energy between the two phases is accounted for by two-way coupling. Bag and stripping breakup regimes are considered for secondary droplet breakup, using the Reitz–Diwakar and the Taylor analogy breakup models. Moreover, a model for droplet evaporation is included. The results reveal a high sensitivity of the spray structure to variations of all investigated parameters. In particular, a decrease in the surface tension or the fuel viscosity, or an increase in the fuel density, lead to less stable liquid structures. As a consequence, smaller droplets are generated and the overall spray surface area increases, leading to faster evaporation and mixing. Furthermore, with the trajectories of the small droplets being strongly influenced by aerodynamic forces (and less by their own inertia), the spray is more affected by the turbulent structures of the gaseous phase and the spray dispersion is enhanced.