Accession Number:

ADA229812

Title:

Feedback Control of Combustion Instabilities: A Case Study in Active Adaptive Control of Complex Physical Systems

Descriptive Note:

Annual letter rept. for FY90 1 Oct 1989-30 Sep 1990,

Corporate Author:

GENERAL ELECTRIC CORPORATE RESEARCH AND DEVELOPMENT SCHENECTADY NY

Personal Author(s):

Report Date:

1990-09-30

Pagination or Media Count:

9.0

Abstract:

This program will address the following issues Previous studies on small 1-kW, premixed, gas-fueled combustors have demonstrated suppression of longitudinal mode combustion instability using pressure or heat release feedback and loudspeaker modulation. Can the same results be achieved on a larger scale 200 kW, liquid-fueled combustor using a more practical actuation means Owing to the high order and nonlinear nature of the processes involved, we would expect that a single, linear, time-invariant LTI controller would be capable of stabilizing the combustor over only a small range of airflows and equivalence ratios. To provide a research test bed, we will modify a 3-in by 3- in, premixed gas combustor to accept liquid fuel admitted through a high bandwidth, Moog servo valve. Fuel flow modulation will be tried first as a means of actuation. If necessary, a fuel pressure feedback loop will be closed around the valve to extend its bandwidth even further. We will then obtain a screech map by measuring the combustor pressure power spectrum at several combinations of airflow rates and equivalence rations. Based on these measurements, and on our experience with the 1-kW combustor, we will select a screeching operating point at which to begin the control system design. js

Subject Categories:

  • Fuels

Distribution Statement:

APPROVED FOR PUBLIC RELEASE