Adaptive Control of Combution Instabilities Using Real-time Modes Observation

Adaptive Control of Combution Instabilities Using Real-time Modes Observation
Author: Clifford Edgar Johnson
Publisher:
Total Pages:
Release: 2006
Genre: Adaptive control systems
ISBN:

Combustion instabilities are a significant problem in combustion systems, particularly in Low NOx Gas Turbine combustors. These instabilities result in large-scale pressure oscillations in the combustor, leading to degraded combustor performance, shortened lifetime, and catastrophic combustor failure. The objective of this research was to develop a practical adaptive active control system that, coupled with an appropriate actuator, is capable of controlling the combustor pressure oscillations without a priori knowledge of the combustor design, operating conditions or instability characteristics. The adaptive controller utilizes an observer that determines the frequencies, phases and amplitudes of the dominant modes of the oscillations in real time. The research included development and testing of the adaptive controller on several combustors and on an unstable acoustic feedback system in order to analyze its performance. The research also included investigations of combustor controllability and combustor stability margin, which are critical issues for practical implementation of an active control system on an industrial combustor. The results of this research are directly applicable to a variety of combustors and can be implemented on full-scale industrial combustion systems.

Thermoacoustic Combustion Instability Control

Thermoacoustic Combustion Instability Control
Author: Dan Zhao
Publisher: Academic Press
Total Pages: 1145
Release: 2023-02-13
Genre: Technology & Engineering
ISBN: 0323899188

Thermoacoustic Combustion Instability Control: Engineering Applications and Computer Codes provides a unique opportunity for researchers, students and engineers to access recent developments from technical, theoretical and engineering perspectives. The book is a compendium of the most recent advances in theoretical and computational modeling and the thermoacoustic instability phenomena associated with multi-dimensional computing methods and recent developments in signal-processing techniques. These include, but are not restricted to a real-time observer, proper orthogonal decomposition (POD), dynamic mode decomposition, Galerkin expansion, empirical mode decomposition, the Lattice Boltzmann method, and associated numerical and analytical approaches. The fundamental physics of thermoacoustic instability occurs in both macro- and micro-scale combustors. Practical methods for alleviating common problems are presented in the book with an analytical approach to arm readers with the tools they need to apply in their own industrial or research setting. Readers will benefit from practicing the worked examples and the training provided on computer coding for combustion technology to achieve useful results and simulations that advance their knowledge and research. Focuses on applications of theoretical and numerical modes with computer codes relevant to combustion technology Includes the most recent modeling and analytical developments motivated by empirical experimental observations in a highly visual way Provides self-contained chapters that include a comprehensive, introductory section that ensures any readers new to this topic are equipped with required technical terms

Combustion Instabilities in Gas Turbine Engines

Combustion Instabilities in Gas Turbine Engines
Author: Timothy C. Lieuwen
Publisher: AIAA (American Institute of Aeronautics & Astronautics)
Total Pages: 688
Release: 2005
Genre: Science
ISBN:

This book offers gas turbine users and manufacturers a valuable resource to help them sort through issues associated with combustion instabilities. In the last ten years, substantial efforts have been made in the industrial, governmental, and academic communities to understand the unique issues associated with combustion instabilities in low-emission gas turbines. The objective of this book is to compile these results into a series of chapters that address the various facets of the problem. The Case Studies section speaks to specific manufacturer and user experiences with combustion instabilities in the development stage and in fielded turbine engines. The book then goes on to examine The Fundamental Mechanisms, The Combustor Modeling, and Control Approaches.

Paper

Paper
Author:
Publisher:
Total Pages: 452
Release: 2001
Genre: Mechanical engineering
ISBN:

Performance Enhancement of Gas-Turbine Combustor by Active Control of Fuel Injection and Mixing Process - Theory and Practice

Performance Enhancement of Gas-Turbine Combustor by Active Control of Fuel Injection and Mixing Process - Theory and Practice
Author: Christian O. Pascherelt
Publisher:
Total Pages: 10
Release: 2001
Genre:
ISBN:

Unstable thermoacoustic modes were investigated and controlled in an experimental low-emission swirl stabilized combustor, in which the acoustic boundary conditions were modified to obtain combustion instability. Axisymmetric and helical unstable modes wore identified for fully premixed combustion These unstable modes were associated with flow instabilities related to the recirculation region on the combustor axis and shear layer in- stabilities at the sudden expansion (dump plane). The combustion structure associated with the different unstable modes was visualized by phase locked images of OH chemi- luminescence, The axisymmetric mode showed large variation of the heat release during one cycle, while the helical modes showed circumferential variations in the location of maximal heat release. Two feedback control methods employed to suppress thermoa- coustic pressure oscillations and to reduce emissions reviewed: proportional acoustic control and fuel modulations. Microphone sensors monitored the combustion process and provided input to the control systems. An acoustic actuation modulated the airflow and thus affected the mixing process and the combustion. Suppression levels of up to 25 dB in the pressure oscillations and a concomitant 10% reduction of NO(x) emissions were obtained. At the optimal control conditions It was shown that the major effect of the control system was to reduce the coherence of the vortical structures which gave rise to the thermoacoustic instability. The specific design of the investigated experimental burner allowed testing the effect of different modulated fuel injection concepts on the combustion instability modes. Symmetric and antisymmetric fuel injection schemes were tested. Suppression levels of up to 12 dB in the pressure oscillations were observed. In some cases concomitant reductions of NO and CO emissions were obtained.