Chapter 19 – MODEL-BASED OPTIMAL ACTIVE CONTROL OF LIQUID-FUELED COMBUSTION SYSTEMS

Advances in modeling combustor are obtained by investigating the shear-flow driven combustion instability. Shear-layer instability produces nonacoustic modes in shear flow. These modes can be predicted and matched to experimental data. These data are combined with a new tool based on the proper orthogonal decomposition (POD) method to yield the reduced-order models of combustion systems. These models shed light on the interactions among hydrodynamics, acoustics, and heat release. A recursive POD (RePOD) algorithm is developed to facilitate a stable online control design by providing suitable updates of the POD modes. Model-based posi-cast controllers produce favorable results as compared to phase-shift controllers using simulation studies on a large-scale combustor model. A theoretical framework for the investigation of shear-flow dynamics is found in modern linear stability analysis in which unstable modes have been characterized as connectivity unstable and absolute unstable.

[1]  Anuradha M. Annaswamy,et al.  Adaptive Algorithms for Control of Combustion , 2001 .

[2]  P. Monkewitz,et al.  LOCAL AND GLOBAL INSTABILITIES IN SPATIALLY DEVELOPING FLOWS , 1990 .

[3]  A. K. Oppenheim,et al.  Mechanism of instabilities in turbulent combustion leading to flashback , 1982 .

[4]  Anuradha M. Annaswamy,et al.  Adaptive low-order posi-cast control of a combustor test-rig model , 2002, Proceedings of the 41st IEEE Conference on Decision and Control, 2002..

[5]  J. Peraire,et al.  OPTIMAL CONTROL OF VORTEX SHEDDING USING LOW-ORDER MODELS. PART II-MODEL-BASED CONTROL , 1999 .

[6]  Craig T. Bowman,et al.  Combustor performance enhancement through direct shear layer excitation , 1990 .

[7]  P. Holmes,et al.  Turbulence, Coherent Structures, Dynamical Systems and Symmetry , 1996 .

[8]  Numerical simulation of the vortex-acoustic wave interaction in a dump combustor , 1986 .

[9]  Ephraim Gutmark,et al.  Large-Scale Coherent Structures as Drivers of Combustion Instability , 1989 .

[10]  Anuradha M. Annaswamy,et al.  Reduced order modeling of reacting shear flow , 2002 .

[11]  J. Daily,et al.  Low-frequency pressure oscillations in a model ramjet combustor , 1991, Journal of Fluid Mechanics.

[12]  C. Fureby.  A computational study of combustion instabilities due to vortex shedding , 2000 .

[13]  R. Sawyer,et al.  Turbulence, combustion, pollutant, and stability characterization of a premixed, step combustor , 1980 .

[14]  R. F. Sawyer,et al.  AN EXPERIMENTAL STUDY OF THE FLOW FIELD OF A TWO DIMENSIONAL PREMIXED TURBULENT FLAME , 1980 .

[15]  J. Whitelaw,et al.  Combustion Oscillations Close to the Lean Flammability Limit , 2000 .

[16]  J. Daily,et al.  Combustion in a turbulent mixing layer formed at a rearward-facing step , 1983 .