Axial Combustor Main Mixer for Stable Lean Liquid Combustion
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Solution Overview
Problem
Lean-staged liquid-fueled aeroengine combustors face combustion instabilities and high NOx and particulate matter emissions, which are not adequately addressed by existing technologies.
Innovation Solution
The design incorporates a swirler with a swirler hub, centerbody, and thermal barrier coatings, featuring non-circular mixer passages, effusion/film cooling passages, and a fuel manifold to stabilize combustion and enhance mixing efficiency, using concentric counter-rotating swirler vanes and fuel injection systems to manage fuel distribution and reduce overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If lean-staged liquid-fueled combustors are used, then NOx and particulate matter emissions are reduced, but combustion instabilities occur
Solution Approach 1:
The combustor is divided into multiple stages with separate fuel injection systems. The pilot burner provides a stable flame core while the main burners inject fuel in controlled stages, allowing the combustion process to be segmented into manageable zones that reduce both emissions and instabilities
Solution Approach 2:
Different regions of the combustor are given different fuel injection characteristics and air mixing ratios. The pilot burner area has different fuel distribution compared to the main burner areas, creating local quality variations that stabilize combustion while maintaining overall lean burn conditions for emission reduction
2Productivity
If conventional mixer designs are used, then device complexity is low, but mixing efficiency is insufficient
Solution Approach 1:
The mixer passages are designed with contoured and curved surfaces rather than straight channels. The contoured annular mixer passage with varying cross-section creates more effective turbulence and mixing while maintaining a compact structure, improving mixing efficiency without proportionally increasing complexity
3Temperature
If thermal barrier coatings are applied to the centerbody, then overheating is prevented, but manufacturing complexity increases
Solution Approach 1:
The centerbody is constructed as a composite structure combining the base material with thermal barrier coatings. This multi-layer composite approach provides superior thermal protection compared to single-material solutions, allowing the combustor to withstand higher temperatures while managing the added manufacturing complexity through standardized coating processes
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 solution provides stable combustion, improved dynamic stability, reduced NOx and particulate emissions, and prevents intermittent flame lift-off, enhancing combustion efficiency and durability.
Implementation Method 1
an inner surface of the centerbody is coated with a thermal barrier coatings (TBC)
Implementation Method 2
The centerbody includes a multiple of effusion/film cooling passages arranged in a circular distribution through an upstream wall of the centerbody
Implementation Method 3
The centerbody includes a multiple of effusion/film cooling passages arranged in a circular distribution through an upstream wall of the centerbody
Data Source
AI summary
A main mixer including a swirler along an axis, the swirler including an outer swirler with a multiple of outer vanes, and a center swirler with a multiple of center vanes and a swirler hub along the axis, the swirler hub including a fuel manifold and an inner swirler with a multiple of inner vanes that support a centerbody, the multiple of inner vanes interconnect the fuel manifold and the centerbody.