Accession Number:

ADP011169

Title:

Active Feedback Control of Combustor Dynamics with Time Delay and Noise

Descriptive Note:

Corporate Author:

CALIFORNIA INST OF TECH PASADENA

Personal Author(s):

Report Date:

2001-06-01

Pagination or Media Count:

18.0

Abstract:

Longitudinal pressure oscillations in a combustion chamber are studied theoretically by means of a low order model obtained by systematic reduction from a complete representation. The formulation is based on the derivation of a generalized wave equation that accommodates the effects of mean flow, combustion, noise and control action. By using spatial averaging, the equations describing the dynamics of the chamber are reduced to a set of coupled ordinary differential equations. The form of the resulting equations is particularly convenient for model reduction and for introducing feedback control terms, while retaining all physical processes. Active feedback control of longitudiual instabilities is then introduced by using the same formulation, rewritten in statespace form. The broad objective of control simulations covered here is to investigate in a unified fashion various aspects of the problem. These include the influences of noise, parameter uncertainties, unmodeled modes and time-delay. A criterion is derived that guarantees the stability of the controlled closed-loop system in the presence of those quantities. The particular controller used here is based on a standard LQR design, but any design technique can be used as long as the stability criterion is fulfilled.

Subject Categories:

  • Mechanics
  • Combustion and Ignition

Distribution Statement:

APPROVED FOR PUBLIC RELEASE