Aft Frame Cooling Passage Design for Combustor Emissions Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current cooling methods for aft frames in gas turbine systems result in working fluid bypassing mixing and combustion, leading to increased flame temperature and NOx emissions, as the cooling fluid is directly dumped into hot gases before reaching the turbine.
Innovation Solution
An aft frame design with radially extending cooling passages and exhaust passages that allow coolant to flow through the frame and into the flow path, ensuring the coolant is reused for cooling without being directly dumped into the hot gas, and a method involving the use of these passages to cool the aft frame effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If working fluid is removed through holes in the aft frame to cool the aft frame, then the aft frame is cooled effectively, but the cooling fluid bypasses mixing and combustion, increasing flame temperature and NOx emissions
Solution Approach 1:
The patent introduces a mediator mechanism (the flow path through the transition piece and combustor) that forces the cooling fluid to travel through the combustion zone where it mixes with fuel and participates in combustion, rather than being directly dumped into hot gases. This intermediary path ensures the cooling fluid is reused productively.
Solution Approach 2:
Instead of discarding the cooling fluid directly into the hot gas stream (which causes harmful effects), the system recovers the cooling fluid by routing it through the combustor where it is mixed with fuel and combusted, thereby recovering its energy value and eliminating the harmful bypass effect.
2Temperature
If cooling fluid is dumped directly into hot gas, then the aft frame is cooled, but energy is wasted and flame temperature increases
Solution Approach 1:
The cooling fluid serves dual purposes: it cools the aft frame structure and then continues to flow through the combustor where it self-services by mixing with fuel and combusting, thereby utilizing its own energy content rather than wasting it. The system makes the cooling fluid work for itself by routing it through the combustion zone.
Solution Approach 2:
The system recovers the energy in the cooling fluid by routing it through the combustor where it is combusted, rather than discarding it directly into the hot gas stream. This recovery process eliminates energy waste and reduces the total energy input required for combustion.
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 effectively cools the aft frame without increasing NOx emissions by ensuring the coolant is reused within the combustion zone for mixing and combustion, thereby maintaining efficient energy transfer and reducing flame temperature.
Implementation Method 1
a generally radially extending cooling passage defined in the body, the cooling passage comprising a first end configured to accept a coolant... a plurality of exhaust passages defined in the body, the exhaust passage including a first end in communication with the cooling passage and a second end configured for communication with the flow path for flowing the coolant therethrough
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An aft frame (50) and a method for cooling an aft frame (50) are disclosed. In one embodiment, an aft frame (50) for a transition piece (26) in a combustor (16) is disclosed. The combustor (16) includes the transition piece (26) and an impingement sleeve (34) at least partially defining a flow path (36) therebetween. The aft frame (50) includes a body (60) and a generally radially extending cooling passage (70) defined in the body (60), the cooling passage (70) comprising a first end (72) configured to accept a coolant (52). The aft frame (50) further includes an exhaust passage (80) defined in the body (60), the exhaust passage (80) including a first end (82) in communication with the cooling passage (70) and a second end (84) configured for communication with the flow path (36) for flowing the coolant (52) therethrough.