LES of Multiphase Reacting Flows in a Gas-Turbine Combustor

The combustion chambers of gas-turbine based propulsion systems involve complex phenomena such as atomization of liquid fuel jets, evaporation, collision/coalescence of droplets, and turbulent mixing of fuel and oxidizer giving rise to spray-flames. Accurate observations and quantitative measurements of these processes in realistic configurations are difficult and expensive. Better understanding of these flows for design modifications, improvements, and exploring fundamental physics demands high-fidelity numerical studies in realistic configurations. Specifically, good predictive capability for swirling, highly turbulent reacting flows in complex geometries is necessary.

Typically, the engineering prediction of such flows in realistic configurations has relied predominantly on the Reynolds-averaged Navier-Stokes equations (RANS). Though computationally efficient, RANS-based models for two-phase reacting flows do not represent the relevant flow quantities accurately even in simple configurations. LES and direct numerical simulation (DNS) techniques have been shown to give good predictions of turbulent flows in simple configurations. This large-scale project, conducted at Stanford University's Center for Integrated Turbulence Simulations (CITS) under the DoE's ongoing Advanced Scientific Computing (ASC) Program, involved developement of new numerical techniques on unstructured grids for turbulent, reacting flows in complex configurations such as those of a real gas-turbine combustion chamber. This computational capability together with subgrid models for droplet dynamics, evaporation, turbulent mixing, and flame dynamics was thoroughly verified and validated against available experimental data to show good predictive capability. Simulations of multiphysics, multiphase flows in a gas-turbine combustor were performed and the numerical tool is being used in design cycle by engine manufacturers.

A series of validation studies to assess predictive capability of the numerical approach and models for droplet dynamics, turbulent combustion, and mixing: (a) solid-particle laden swirling, coaxial combustor, (b) evaporating spray in a coannual combustor, (c) methane-based turbulent reacting flow in a coaxial combustor, (d) breakup of a liquid jet, (e) liquid jet in a cross flow (Moin and Apte, 2006).

• Apte S.V., Mahesh, K., and Moin, P. 2008, Large-eddy simulation of evaporating spray in a coaxial combustor, Proceedings of the Combustion Institute, Vol. 32., to appear January 2009. (PDF)

• Apte S.V., Mahesh, K., Gorokhovski, M., and Moin, P., 2008, Stochastic modeling of atomizing spray in a complex swirl injector using large-eddy simulation, Proceedings of the Combustion Institute, Vol. 32, to appear January 2009. (PDF)

• Moin, P., and Apte S.V., 2006, Large-eddy simulation of realistic gas turbine combustors, AIAA Journal, Vol. 44(4), pp. 698-708 (Invited Publication in the Special Issue on Combustion Modeling and LES: Development and Validation Needs for Gas Turbine Combustors). (PDF)

• Mahesh, K., Constantinescu, Apte, S.V., G., Iaccarino, G., Ham, F, and Moin, P., 2006, Large-eddy simulation of reacting turbulent flows in complex geometries, ASME Journal of Applied Mechanics, Vol. 73, pp. 375-381 (Invited Publication). (PDF)

• Schluter, J., Apte, S.V., Kalitzin, G., Weide, E., Alonso, J.J., and Pitsch, H., 2005, Large scale integrated LES-RANS simulations of a gas turbine engine, Annual Research Brief, Center for Turbulence Research, Stanford University and NASA AMES, pp. 111-120. (PDF)

• Moin, P., and Apte, S.V., 2004, Large eddy simulation of realistic gas turbine combustors, Simplicity, Rigor and Relevance in Fluid Mechanics, F.J. Higuera, J. Jimenez and J.M. Vega.  (Eds.), in honor of Prof. Amanable Linan, Spain, Barcelona (invited publication).

• Apte, S.V., Mahesh, K., Ham, F., and Constantinescu, G., 2004, Large-eddy simulation of multiphase flows in complex combustors, Computational Methods in Multiphase Flows, Vol. II, pp. 53-62. (PDF)

• Apte S. V., and Ghosal, S., 2004, A presumed PDF model for droplet evaporation/condensation in complex flows, Annual Research Briefs, Center for Turbulence Research, Stanford University and NASA-AMES, pp. 209-221. (PDF)

• Ham, F., Apte, S.V., Young, Y-N., and Herrmann, M., 2004, A hybrid Eulerian-Lagrangian method for LES of atomizing spray, Computational Methods in Multiphase Flows, Vol. II,  pp. 313. (PDF)

• Kim, W.W., Apte, S.V., Herrmann, M., & Ham, F., 2004, Liquid film modeling in jet engine fuel injectors, Proceedings of the Summer Program, Center for Turbulence Research, Stanford University and NASA-AMES, pp. 305-314. (PDF)

• Apte, S. V., Mahesh, K., Moin, P., and Oefelein, J.C., 2003, Large-eddy simulation of swirling particle-laden flows in a coaxial-jet combustor, International Journal of Multiphase Flow, Vol. 29, pp. 1311-1331. (PDF)

• Apte, S. V., Gorokhovski, M., and Moin, P., 2003, LES of atomizing spray with stochastic modeling of spray break-up, International Journal of Multiphase Flows, Vol 29, pp. 1503-1522. (PDF)

• Ham, F., Apte, S. V., Iaccarino, G., Wu, X., Constantinescu, G., Mahesh, K., and Moin, P., 2003, Unstructured LES of reacting multiphase flows in realistic gas-turbine combustors, Annual Research Briefs, Center for Turbulence Research, Stanford University and NASA-AMES, pp. 139-160. (PDF)

• Mahesh, K., Constantinescu, G., Apte, S.V., Iaccarino, G., Ham, F., and Moin, P. 2002, Progress towards large-eddy simulation of turbulent reacting and non-reacting flows in complex geometries, Annual Research Briefs, Center for Turbulence Research, Stanford University and NASA Ames, pp. 115-142. (PDF)

• Mahesh, K., Constantinescu, G., Apte, S.V., Iaccarino, G.,  and Moin, P. 2001, Large-eddy  simulation of gas-turbine combustors, Annual Research Briefs, Center for Turbulence  Research, Stanford University and NASA Ames, pp. 3-17. (PDF)