Fuel Injector Air Swirler With Canted Guide for Flow Stability
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Solution Overview
Problem
Existing fuel injector assemblies for gas turbine engines suffer from flow disturbances and combustor instabilities due to recirculating air at the interface between the nozzle guide and injector nozzle, leading to inefficiencies and performance issues.
Innovation Solution
A fuel injector assembly with a canted flow guide surface on the first swirler wall that extends radially inward and has a tapered geometry, guiding swirled air smoothly into the inner passage, reducing low pressure regions and minimizing flow separation, thereby stabilizing the airflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If air swirler is used in fuel injector assembly, then air-fuel mixing is improved, but flow disturbances and combustor instabilities occur due to recirculating air
Solution Approach 1:
The swirler assembly is segmented into distinct functional zones: an outer annular passage for primary swirl generation and an inner passage for stable airflow. This segmentation allows the air-fuel mixing function to be separated from the stable flow function, enabling both high mixing efficiency and combustor stability simultaneously.
Solution Approach 2:
A flow guide surface acts as an intermediary element between the outer and inner passages. This mediator structure directs the swirled air from the outer passage into the inner passage in a controlled manner, preventing harmful recirculation while maintaining the beneficial swirl for mixing. The flow guide surface translates the rotational motion into a stable axial flow pattern.
2Device complexity
If conventional swirler design is used, then compact structure is achieved, but flow separation and low pressure regions cause instability
Solution Approach 1:
The flow guide surface employs a curved, tapered geometry that smoothly transitions airflow from the outer annular passage to the inner passage. This curved surface design eliminates sharp corners and abrupt transitions that would cause flow separation, maintaining attached flow and preventing low pressure region formation while adding minimal structural complexity.
3Ease of manufacture
If radial swirler wall is used, then easy manufacturing is achieved, but recirculating air causes flow disturbances
Solution Approach 1:
The swirler design transitions from a symmetric radial wall configuration to an asymmetric structure with a tapered flow guide surface that is angled relative to the radial direction. This asymmetric geometry prevents the formation of recirculating zones by creating a pressure gradient that drives flow unidirectionally from the outer to inner passage, eliminating flow disturbances while remaining manufacturable.
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
The canted flow guide surface enhances airflow stability, reducing turbulence and downstream combustor instabilities, improving the efficiency and performance of the gas turbine engine.
Implementation Method 1
minimizing flow separation
Implementation Method 2
air swirler structure with a first swirler wall and an air swirler passage
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A turbine engine assembly includes an air swirler structure (66), an injector nozzle (108) and a nozzle guide (70). The air swirler structure (66) includes a swirler wall (82), an inner passage (134) and an air swirler passage (122). The swirler wall (82) includes a flow guide surface (92). At least an inner portion (110) of the flow guide surface (92) has a frustoconical geometry. The inner passage (134) extends axially along an axis (72) within the air swirler structure (66) to a swirler outlet (140). The air swirler passage (122) extends radially into the air swirler structure (66), longitudinally along the flow guide surface (92) and to the inner passage (134). The injector nozzle (108) projects axially into the inner passage (134). The nozzle guide (70) couples the injector nozzle (108) to the air swirler structure (66). The nozzle guide (70) is axially abutted against the swirler wall (82).