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Method and Apparatus for Enhanced Flameholding in Augmentors

Inactive Publication Date: 2014-11-20
THE BOARD OF TRUSTEES OF THE LELAND STANFORD JUNIOR UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The invention is regarding a new design for a jet engine flame holder bluffbody. The bluffbody has a rounded leading edge, a rectangular mid-body, and a triangular trailing edge. The trailing edge has digitated cutouts with a wedge shape, a rectangular recess, or tapered sidewalls. The material digits can have various shapes, such as square, rectangular, circular, or triangular. The leading edge, mid-body, and trailing edge can all be hollow structures. Additionally, the material digits can have a curved triangular shape with a thin-walled structure. The technical effects of this design include improved cooling, reduced pressure drop, and improved durability.

Problems solved by technology

The two phenomena are concomitantly observed whenever the bluffbody flame approaches blowout, and that the presence of an oscillatory wake can accelerate the flame blowout phenomenon by introducing a significant amount of low temperature fluid from the surroundings to the reaction zone such that the heat release from the chemical reactions (or rate of branching reactions) cannot keep up with the cooling effect due to the entrainment of cold gases (or rate of quenching reaction).

Method used

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  • Method and Apparatus for Enhanced Flameholding in Augmentors
  • Method and Apparatus for Enhanced Flameholding in Augmentors
  • Method and Apparatus for Enhanced Flameholding in Augmentors

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Embodiment Construction

[0032]The current invention provides an improvement of the lean blowout limit of bluffbody stabilized flames. The flame configuration includes a hybrid of partially and fully premixed flames, which is demonstrated by injecting methane jets from a streamline-shaped bluffbody into a fully premixed methane / air crossflow. According to the invention geometric configurations of the bluffbody include a base that has two-dimensionally modified geometries and three-dimensional local cavities. According to one embodiment, the blowout limit of a hybrid configuration is extended by up to 12% (in terms of the equivalence ratio of the crossflow). Gas chromatographic sampling and particle image velocimetry (PIV) show that high fuel mole fraction regions coexist with regions of low speed flow for the modified geometries. Further, PIV analysis shows that the downstream flow fields of the modified bases generally have a larger number of incoherent vortices and lower strain rate in comparison with tho...

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Abstract

A jet engine flame holder bluffbody is provided that includes a leading edge that is rounded, a mid-body having a rectangular cross-section, and a trailing edge, where the trailing edge includes a rectangular cross-section having digitated cutouts from the rectangular cross-section, where the tailing edge projects upward according to a digitated cross-section, where material digits remain between consecutive pairs of the digitated cutouts.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is a continuation-in-part of U.S. patent application Ser. No. 12 / 806,958 filed Aug. 24, 2010, which is incorporated herein by reference. U.S. patent application Ser. No. 12 / 806,958 filed Aug. 24, 2010 claims benefit of U.S. Provisional Patent application 61 / 236,456 filed Aug. 24, 2009, which is incorporated herein by reference.STATEMENT OF GOVERNMENT SPONSORED SUPPORT[0002]This invention was made with Government support under contract FA9550-08-C-0039 awarded by U.S. Air Force. The Government has certain rights in this invention.FIELD OF THE INVENTION[0003]The current invention relates to jet engines. More particularly, the invention relates to jet engine flame holder bluffbodies.BACKGROUND OF THE INVENTION[0004]The lean blowout limit of bluffbody flames has been studied extensively for several decades since the improvement of flame stability in the lean environment is a primary purpose for using bluffbodies in various pr...

Claims

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Application Information

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IPC IPC(8): F23R3/18
CPCF23R3/18
Inventor KIM, WOOKYUNGMUNGAL, MARK GODFREYPITSCH, HEINZ GUENTER
Owner THE BOARD OF TRUSTEES OF THE LELAND STANFORD JUNIOR UNIV