US 6,601,393 B2 · Method and device for modulation of a flame

Abstract

This invention relates to air breathing engines, such as ramjets, scramjets and internal combustion, and more particularly to an active combustion control device for a combustor. In more particularity, the present invention relates to a method and apparatus that applies active combustion control technology to advanced propulsion devices and closed-loop fuel injection at sub-harmonic frequencies of the instability frequency of the combustor. The problem of limited actuator frequency response is addressed by injecting fuel pulses at sub-harmonic frequencies of the instability. The fuel may be liquid, solid or gas. To achieve this desired result, a closed loop controller is designed to determine sub-harmonic frequencies using a divider to divide the instability frequency of a combustor, yielding a fraction of the harmonic frequency. Also, this invention also combines open loop injection control with closed loop injection control to obtain enhanced engine performance, which includes extension of the stable combustion zone.

Claims16

Dependent claims

A method of active control modulation of a flame in a combustor having an instability frequency by injecting pulsed fuel via a plurality of actuators having at least one closed loop actuator and at least one open loop actuator, comprising:

feeding a fluid flow into said combustor through an inlet, wherein instabilities in said combustor produce natural oscillations in the fluid flow;
generating a signal detecting the pressure oscillations within said combustor;
engaging a closed loop control device operatively to said at least one closed loop actuator and responsive to a sensor, wherein said closed loop control device prompts the closed loop actuator to inject the pulsed fuel into a shear layer of said combustor;
injecting the pulsed fuel from the closed loop actuator into said combustor, wherein the pulsed fuel from said closed loop actuator controls the amplitude of the pressure oscillations in said combustor by modulating the natural oscillations;
engaging an open loop control device operatively coupled to said at least one open loop actuator, wherein said open loop control device prompts said at least one open loop actuator to inject pulsed fuel into said combustor at a driving frequency;
and
injecting pulsed fuel from said open loop actuator into said combustor at said driving frequency.

4 more elements

Dependencies are inferred from the claim text.

Method and device for modulation of a flame

Life of this patent

Method and device for modulation of a flame

Life of this patent

Abstract

Claims16