Combustor Cowl Notch Tangential Airflow Flame Stability
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Solution Overview
Problem
Gas turbine engines face poor flame stability due to high velocity components of compressed air normal to the fuel nozzle swirlers, leading to inefficient air distribution.
Innovation Solution
A gas turbine engine design featuring a fuel nozzle with a stem and head, where a cowl with a notch redirects compressed air around the stem, minimizing high velocity air flow to the fuel nozzle inlet, and a collar directs air flow tangentially to reduce radial velocity components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If compressed air is supplied directly to the fuel nozzle inlet, then air flow quantity is sufficient, but high velocity radial components cause poor flame stability
Solution Approach 1:
A cowl is introduced as an intermediary component between the compressed air source and the fuel nozzle. The cowl redirects the compressed air flow to approach the fuel nozzle tangentially rather than radially, eliminating high velocity components normal to the fuel nozzle inlet while maintaining sufficient air flow quantity for combustion
Solution Approach 2:
The air flow path is segmented into two distinct zones: a radial flow zone away from the fuel nozzle inlet and a tangential flow zone approaching the fuel nozzle. The cowl creates this segmentation by redirecting air flow around the fuel nozzle stem, allowing the radial and tangential components to be separated in space
2Reliability
If a cowl with notch is introduced to redirect air flow, then flame stability improves, but device complexity increases
Solution Approach 1:
The cowl is integrated with the fuel nozzle assembly, with the collar forming part of the cowl structure. This merging reduces the number of separate components while maintaining the air flow redirection function, thereby improving flame stability without proportionally increasing device complexity
Solution Approach 2:
The cowl with collar serves multiple functions: it redirects compressed air flow tangentially to the fuel nozzle, provides structural support for the fuel nozzle assembly, and defines the combustion chamber geometry. This multi-functionality reduces the need for additional components
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enhances air distribution to the fuel nozzle, improving flame stability and reducing high velocity air flow, resulting in more efficient combustion.
Implementation Method 1
An edge of the cowl defining the notch comprises a collar formed to extend from a surface of the cowl to direct the flow of air around the notch and to an inlet of the head
Data Source
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AI summary
A gas turbine engine includes a combustion system (200). The combustion system includes a combustor positioned in a chamber created by an outer wall. A compressor, such as a centrifugal compressor provides a flow of compressed air into the chamber along an inner surface of the outer wall since an inlet for the flow of compressed air is outboard of the combustor. The pressurized flow of air may is redirected by a cowl (552) included in the chamber. The cowl ncludes a collar (516) defining a notch (504) in the cowl. The collar redirects the flow of pressurized air so as to minimize a high velocity component of the flow of pressurized air flowing radially toward a central axis of the engine prior to entering a head (226) of a fuel nozzle (224) included in the combustion system.