N101-028 TITLE: Computational Characterization of Aeroengine Combustor/Augmentor Fuel Injectors

TECHNOLOGY AREAS: Air Platform

ACQUISITION PROGRAM: Joint Strike Fighter

OBJECTIVE: Develop advanced computational methodologies and technologies for detailed simulation and characterization of aeroengine combustor/ augmentor fuel injector performance.

DESCRIPTION: Aeroengine combustor/augmentor performance (stability, efficiency, durability and emissions) is critically dependent on the details of fuel injection and atomization. Quantification and/or prediction of fuel atomization are still at relatively primitive levels, particularly when compared to other reacting flow phenomena occurring in these devices. This is due to the complexity of the two-phase flow physics and the geometrical complexity of injectors as well as the inherent limitations in experimental measurement in the vicinity of the atomizing fuel. Recent advancements in numerical methods and increases in computational power have presented computational simulation as a viable alternative to traditional approaches in the quantification of fuel atomization. An innovative solution is sought to advance the capabilities and transition numerical/computational technologies towards the simulation of injectors operating under realistic conditions. The benefit of such simulations will be utilized to reduce the number of experiments while improving injector design and/or improving the fidelity of the models. The developed computational methodologies need to be able to reproduce fuel atomization in geometrically complex injectors that employ aerodynamic forces to atomize the fuel. Such atomization is very complex and includes the evolution and breakup of contiguous liquid fuel, dense spray dynamics, spray wall interactions, and disperse phase dynamics in a high Reynolds number vortical flow. In addition, for aeroengine combustor/augmentor applications these phenomena occur over a range of global pressures and temperatures and may be further complicated by the use of alternative fuels.

The computational model is to be sensitive to geometric, fuel type and operating condition changes and be able to reproduce the injector internal and external two phase flow. Atomization must be due to aerodynamic breakup and should include spray-wall interaction.

PHASE I: Design and demonstrate the feasibility of an innovative spray atomization computational technology. Identify and formulate the computational technologies that need to be developed to achieve the injector characterization.

PHASE II: Further develop the injector characterization computational technology. Validate prototype with far field measurements. Demonstrate the prototype for at least two relevant injectors.

PHASE III: Finalize the technology and transition to the appropriate engine platform.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: Successful development of the advanced computational methodologies and models that can predict fuel injector performance should enable engineers to enhance injector design and improve the performance, operability and durability of combustion devices relevant to tactical and commercial transport aircraft. This is particularly important for improved fuel economy and range of these platforms.

REFERENCES:
1. Ménard, T, Tanguy, S., Berlemont, A., "Coupling Level Set/VOF/Ghost Fluid Methods: Validation and Application to 3D Simulation of the Primary Break-up of a Liquid Jet," Inter. J. of Multiphase Flow, v. 33, 510-524 (2007)

2. Gorokhovski, M. and Herrmann, M., "Modeling Primary Atomization", Annual Review of Fluid Mechanics. Volume 40, Page 343-366, Jan 2008

3. Arienti, M. and Soteriou, M.C., "Dynamics of Pulsed Jet in Crossflow" GT2007-27816, Proceedings of ASME Turbo Expo 2007

4. Inoue, C. , Watanabe T. and Himeno T., "Study on Atomization Process of Liquid Sheet Formed by Impinging Jets" AIAA-2008-4847

5. Liovic, P., Lakehal, D., "Multi-physics treatment in the vicinity of arbitrarily deformable gas�liquid interfaces," Journal of Computational Physics 222 (2007) 504�53

6. Ohta, S. and A. Matsuo, Horikawa, A., "Numerical And Experimental Investigations on Atomization of Air-blasted Liquid Film", AIAA-2009-0997

KEYWORDS: Combustor Spray M&S; Augmentor Spray M&S; CFD; VAATE; Atomization; Gas Turbine Engine

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