Micro-channel Cooling for Segmented Combustor Nozzles
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Solution Overview
Problem
Conventional axially staged fuel injection combustion systems in gas turbines face challenges in balancing airflow for cooling and maintaining emissions compliance across the full range of operation, particularly in reducing NOx and CO emissions.
Innovation Solution
A segmented annular combustion system with integrated combustor nozzles featuring micro-channel cooling and axially staged fuel injection, where fuel-air mixtures are pre-mixed and injected in primary and secondary combustion zones, with air inlet holes and micro-channels for efficient cooling and emission control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If conventional axially staged fuel injection combustion systems are used to reduce NOx and CO emissions, then emissions compliance is improved, but balancing airflow for cooling and maintaining performance across full operation range becomes difficult
Solution Approach 1:
The combustor is divided into multiple segments with individual nozzles, each equipped with independent cooling airflow control. This segmentation allows separate adjustment of cooling airflow to each nozzle, enabling precise balancing of cooling requirements across different operational conditions while maintaining emission compliance through the staged fuel injection system.
2Temperature
If cooling airflow is increased to maintain combustor temperature control, then cooling effectiveness is improved, but airflow available for fuel-air mixture injection is reduced
Solution Approach 1:
Cooling airflow is introduced through micro-channels in the nozzle structure before the main combustion process. This preliminary cooling action prepares the nozzle surfaces to withstand high temperatures, allowing the system to maintain effective cooling without significantly compromising the airflow available for fuel-air mixture injection, as the cooling air is pre-positioned and does not interfere with the primary combustion airflow paths.
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 system effectively reduces NOx and CO emissions by optimizing airflow and cooling, enhancing combustion efficiency and maintaining emissions compliance across varying operational conditions.
Implementation Method 1
a first set of micro-channel cooling passages extending through the inner liner segment and a second set of micro-channel cooling passages extending through the outer liner segment. Each micro-channel cooling passage has an inlet hole in communication with the cooling flow gap and an outlet hole
Implementation Method 2
Air from the compressor discharge casing may flow through the cooling flow gap formed between the inner liner segment and the inner impingement panel and/or through the cooling flow gap formed between the outer liner segment and the outer impingement panel
Implementation Method 3
An inner impingement panel may be disposed within the combustor nozzle and radially spaced from the inner liner segment to form a cooling flow gap therebetween. An outer impingement panel may be disposed within the combustor nozzle and radially spaced from the outer liner segment to form a cooling flow gap therebetween
Implementation Method 4
Each integrated combustor nozzle is fluidly coupled to at least one fuel injection module, which includes a fuel nozzle portion and a plurality of fuel injection lances. The fuel nozzle portion introduces a first fuel-air mixture to a primary combustion zone, and the fuel injection panel introduces a second fuel-air mixture into a secondary combustion zone
Implementation Method 5
The fuel nozzle portion introduces a first fuel-air mixture to a primary combustion zone, and the fuel injection panel introduces a second fuel-air mixture into a secondary combustion zone axially downstream of the first combustion zone
Implementation Method 6
Oxidization of molecular nitrogen in the gas turbine depends upon the temperature of gas located in a combustor, as well as the residence time for reactants located in the highest temperature regions within the combustor
Data Source
AI summary
A segmented annular combustion system includes integrated combustor nozzles, each of which has a fuel injection panel disposed radially between an inner liner segment and an outer liner segment. The fuel injection panel includes an aft end portion, a first side wall, a second side wall, premixing channels defined between the first side wall and the side wall, and injection outlets defined along at least one of the first side wall and the second side wall. The aft end portion defines a turbine nozzle portion. An interior portion between the first side wall and the second side wall includes walls that extend between the first and second side walls, thereby partitioning the interior portion into discrete air cavities. The liner segments may be cooled by micro-channel cooling passages, which may be fluidly coupled to a collection trough.