Robert N Lawrence

US Patent:

57480907, May 5, 1998

Filed:

Jul 16, 1997

Appl. No.:

8/892833

Inventors:

Stephen E. Borg - Norfolk VA
James W. West - Hampton VA
Robert M. Lawrence - Hampton VA
Samuel E. Harper - Newport News VA
David W. Alderfer - Newport News VA

Assignee:

The United States of America as represented by the Administrator of the
National Aeronautics and Space Administration - Washington DC

International Classification:

G08B 1712

US Classification:

340578

Abstract:

A device has been developed which monitors the presence of a flame within a combustion chamber. The optical flameout detection system responds to gross changes in combustor light intensity, which is monitored in two spectral bands. A photomultiplier tube makes optical measurements in the ultraviolet portion of the spectrum, and a silicon photodiode covers the visible region. The detectors, located outside the combustion chamber, receive the light energy radiated from the combustion process through fiber optic probes designed to operate in a high pressure environment. The optical fibers are aimed diagonally through the center of the injector at the combustion chamber wall downstream of the injector. The probed observe events occurring within a narrow conical-shaped field of view so that the system can quickly detect longitudinal movement of the flame front away from the injector. If a change in intensity of the flame is detected, the fuel supply to the combustion chamber is shut off, limiting the amount of unburned fuel in the combustion chamber which could reignite.