Combustor Collar Purge Paths for Secondary Fuel Injector Protection
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Solution Overview
Problem
Gas turbine engines face challenges with undesirable emissions and inefficiencies due to incomplete combustion and high operating temperatures, necessitating improved combustion systems to enhance efficiency and reduce emissions.
Innovation Solution
A combustor design incorporating a premixer fuel injector and a collar surrounding a secondary fuel injector, which defines upstream and downstream purge paths with varying flow areas to manage purge airflow effectively, reducing exhaust gas ingestion and enhancing combustion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a secondary fuel injector is placed in the transition duct opening, then combustion efficiency is improved, but exhaust gas ingestion increases
Solution Approach 1:
The collar is divided into multiple segments or sections with different aperture configurations. The upstream portion has larger apertures to allow sufficient purge airflow, while the downstream portion has smaller apertures to restrict exhaust gas ingestion. This segmentation allows each section to perform its specific function optimally.
Solution Approach 2:
Different portions of the collar have different aperture sizes tailored to their specific functional requirements. The upstream portion requires larger apertures for high purge airflow to prevent exhaust gas from reaching the secondary fuel injector, while the downstream portion requires smaller apertures to minimize exhaust gas ingestion into the combustor.
2Object-generated harmful factors
If purge airflow is increased to reduce exhaust gas ingestion, then emissions are reduced, but pressure drop increases
Solution Approach 1:
The collar apertures are segmented into upstream and downstream portions with different sizes. This segmentation allows the system to provide sufficient purge airflow through the upstream portion while limiting the pressure drop through the downstream portion, achieving a balance between emissions control and pressure loss.
Solution Approach 2:
The aperture sizes in the collar are specifically designed with different parameters for upstream and downstream portions. The upstream apertures are larger to maintain high flow capacity for purge purposes, while downstream apertures are smaller to reduce pressure drop, optimizing the overall system performance.
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 design improves combustion efficiency by minimizing exhaust gas ingestion and optimizing purge airflow, leading to reduced emissions and extended engine life.
Implementation Method 1
The collar includes a plurality of upstream apertures facing the upstream side of the opening and a plurality of downstream apertures facing the downstream side of the opening. The plurality of upstream apertures define the upstream purge path and the plurality of downstream apertures define the downstream purge path.
Data Source
AI summary
A combustor includes a premixer fuel injector that injects fuel into the combustor and ignites mixture of the fuel and compressed air to produce exhaust gas, a transition duct through which the exhaust gas passes, a secondary fuel injector disposed in an opening of the transition duct for providing further fuel to the exhaust gas, and a collar fixedly coupled to the transition duct and positioned to surround the secondary fuel injector. The collar cooperates with the secondary fuel injector to define an upstream purge path disposed on an upstream side of the opening and a downstream purge path disposed on a downstream side of the opening by a flow direction of the exhaust gas that each provides a flow communication between an exterior of the transition duct and an interior of the transition duct. The upstream purge path has a larger flow area than the downstream purge path.