Staged Trapped Vortex Combustor for Emission Control
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Solution Overview
Problem
Conventional combustors face challenges in achieving complete combustion and minimizing NOx and CO emissions, particularly in ultra-compact designs where pressure losses and residence time are critical.
Innovation Solution
The implementation of a combustor assembly with axially staged annular trapped vortex cavities, where fuel and air are injected tangentially to form an annular rotating vortex, enhancing mixing and gradually introducing combustion products into the main flow, thereby improving combustion efficiency and reducing emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a single trapped vortex cavity is used in an ultra-compact combustor, then the combustor size and weight are reduced, but the residence time is insufficient for complete combustion and emission control
Solution Approach 1:
The single trapped vortex cavity is divided into multiple smaller cavities arranged in series. This segmentation allows the combustion process to occur in stages, with each cavity providing a portion of the required residence time. The total combustion time is distributed across multiple cavities, enabling complete combustion and emission control while maintaining a compact overall combustor volume.
2Productivity
If the combustor length is increased to provide sufficient residence time for complete combustion, then combustion efficiency improves, but the overall system weight and size increase
Solution Approach 1:
Instead of using a single long combustor, the system employs multiple compact trapped vortex cavities arranged in a compact configuration. Each cavity contributes to the overall combustion process, providing the necessary residence time without requiring a long axial length. This segmented approach achieves high combustion efficiency while maintaining a lightweight, compact system.
3Device complexity
If fuel and air are injected axially into the combustor, then the injection system is simple, but mixing is insufficient for complete combustion and low emissions
Solution Approach 1:
The injection system uses tangential injection ports that introduce fuel and air tangentially into each trapped vortex cavity. This tangential injection creates a swirling flow pattern and trapped vortex within each cavity, dramatically enhancing fuel-air mixing. The curved vortex flow ensures thorough mixing and complete combustion, achieving low emissions while maintaining a relatively simple injection system design.
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 approach enables complete combustion with reduced NOx and CO emissions, achieving efficient energy extraction while maintaining a compact design and minimizing weight, by providing additional time for fuel-air mixture burn without increasing combustor length.
Implementation Method 1
fuel and air are injected tangentially to provide for an injection of air and fuel to form an annular rotating trapped vortex of a fuel and air mixture within a respective annular trapped vortex cavity
Implementation Method 2
The annular rotating trapped vortex of the fuel and air mixture at the cavity openings of the at least two annular trapped vortex cavities is substantially perpendicular to the downstream flow of the main fluid
Implementation Method 3
at least two annular trapped vortex cavities staged axially spaced apart... providing additional time for fuel-air mixture burn without increasing combustor length
Data Source
AI summary
A gas turbine engine and combustor assembly including a combustor liner defining therein a combustion chamber for the downstream flow of a main fluid. At least two axially spaced apart annular trapped vortex cavities are located on the combustor liner and staged axially and radially spaced apart. A cavity opening is located at a radially inner end of each of the at least two annular trapped vortex cavities. A plurality of injectors are configured tangentially relative to circular radially outer wall extending between an aft wall and a forward wall of each cavity to provide for an injection of air and fuel to form an annular rotating trapped vortex of a fuel and air mixture within a respective annular trapped vortex cavity. The annular rotating trapped vortex of the fuel and air mixture at the cavity openings is substantially perpendicular to the downstream flow of the main fluid.