Staged Fuel Injection Combustor for Gas Turbine Efficiency
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Solution Overview
Problem
Conventional gas turbine combustion systems face limitations in achieving higher firing temperatures while maintaining low NOx emissions due to the sensitivity of NOx emissions to operating temperatures, which restricts further efficiency improvements.
Innovation Solution
The implementation of a staged injection system in gas turbines, where air and fuel are injected axially downstream of the primary injector, reducing reactant residence time at high temperatures and incorporating a one-way continuous coolant flowpath through stator blades to enhance cooling and aerodynamic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If higher operating temperatures are used to improve engine efficiency, then engine efficiency is improved, but NOx emissions increase
Solution Approach 1:
The combustion system is divided into multiple zones with different temperature characteristics. The linear cavity creates a segmented flow pattern where fuel-rich zones and fuel-lean zones are spatially separated, allowing high temperatures in the combustion zone while maintaining lower temperatures in the exhaust zone, thus reducing NOx formation
Solution Approach 2:
Different regions of the combustion system are given different thermal and compositional characteristics. The linear cavity structure creates localized fuel-rich regions followed by fuel-lean regions, enabling high efficiency combustion in specific zones while controlling emissions in other zones
2Temperature
If more compressor air is directed to staged injectors axially spaced downstream, then firing temperature is increased, but aerodynamic pressure losses increase
Solution Approach 1:
The cooling air requirement and combustion air requirement are merged into a single flow path through the linear cavity. Air that would otherwise be used for cooling turbine blades is instead directed through the linear cavity to support staged combustion, eliminating the need for separate cooling air extraction and reducing overall pressure losses
Solution Approach 2:
The linear cavity structure serves multiple functions simultaneously: it provides aerodynamic cooling for the combustor liner, enables staged fuel injection for emission control, and acts as a flow mixing region. This multi-functionality reduces the need for separate dedicated systems and minimizes overall pressure losses
3Object-generated harmful factors
If a linear cavity structure is implemented for staged injection, then NOx emissions are reduced, but device complexity increases
Solution Approach 1:
The linear cavity structure is integrated within the existing combustor architecture, with fuel injectors positioned along the cavity and cooling passages embedded within the cavity walls. This nested arrangement achieves complex emission control functionality without adding significant external structural complexity
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 allows for increased firing temperatures and improved engine efficiency while minimizing NOx emissions and aerodynamic pressure losses, optimizing the use of cooling air and reducing system pressure losses.
Implementation Method 1
a one-way continuous coolant flowpath through an airfoil of a stator blade in the turbine, the coolant flowpath including an intake section that defines a swirl flow of the coolant
Implementation Method 2
the coolant flowpath including an intake section that defines a swirl flow of the coolant
Implementation Method 3
combustion systems within combustion or gas turbine engines
Data Source
Figure 1
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AI summary
A gas turbine 12 that includes: a combustor 13 coupled to a turbine that define a working fluid flowpath 37; a compressor discharge cavity; a staged injection system that includes the forward injector 21 and a staged injector 51; a stator blade positioned extending across the working fluid flowpath between an inboard sidewall and an outboard sidewall. A one-way continuous coolant flowpath that includes: an intake section that comprises an upstream port connected to the compressor discharge cavity and a downstream port formed through one of the inboard and outboard sidewalls; an outtake section that comprises a downstream port connected to the staged injector and an upstream port formed through the same one of the inboard and outboard sidewalls; and a cooling circuit extending through an interior of the airfoil of the stator blade and connecting to the downstream port of the intake section and the upstream port of the outtake section.