Combustor Spring Clip Cooling via Throttle Section Gap
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Solution Overview
Problem
The existing combustor designs face challenges in reliably cooling the spring clip at the connection section between the combustor basket and the transition piece, as the small amount of leaked air used for cooling is insufficient to prevent burnout due to exposure to high-temperature combustion gas, especially with rising combustion gas temperatures for higher gas turbine efficiency.
Innovation Solution
A combustor configuration that includes a throttle section within the gap between the combustor basket and the transition piece, which narrows the opening area, increasing the flow rate of leaked air and utilizing a cooling device to efficiently cool the throttle section through impingement, convection, or film cooling, thereby reducing the inflow of combustion gas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling air is blown directly to cool the spring clip, then the spring clip is cooled, but the flame temperature rises and nitrogen oxide emission increases
Solution Approach 1:
The throttle section acts as an intermediary component that modifies the flow characteristics of leaked air. By narrowing the opening area, it accelerates the leaked air flow and directs it to form a protective curtain between the combustion gas and spring clip, cooling the spring clip without requiring direct injection of cooling air that would raise flame temperature
Solution Approach 2:
The system utilizes the leaked air that naturally flows from the outside into the gap across the spring clip as the cooling medium. The throttle section enhances the effectiveness of this self-available cooling resource by increasing its flow rate and directing it optimally, eliminating the need for separate cooling air supply systems
2Device complexity
If leaked air is used to cool the spring clip, then the system structure is simple, but the cooling effect is insufficient due to small amount of leaked air
Solution Approach 1:
The throttle section changes the flow parameters of the leaked air by narrowing the opening area, which increases the flow rate and velocity of the leaked air. This parameter change transforms the insufficient cooling effect of small-amount leaked air into an effective cooling mechanism that can handle rising combustion gas temperatures
Solution Approach 2:
The throttle section is provided in the opening portion of the gap, creating a three-dimensional flow control structure that narrows the opening area. This dimensional modification redirects and accelerates the leaked air flow in a specific pattern, forming a protective flow curtain that enhances cooling efficiency without adding complex mechanical components
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 prevents burnout of the spring clip by increasing the flow rate of leaked air and enhancing cooling efficiency, ensuring reliable operation and higher efficiency of the gas turbine.
Implementation Method 1
cooling device for cooling the throttle section
Implementation Method 2
a way to cool the spring clip by using leaked air which flows from the outside into the gap across the spring clip
Implementation Method 3
a throttle section that is provided in an opening portion of the gap that is opened to the transition piece on the tip side of the combustor basket, and narrows an opening area of the opening portion, compared to the base end side of the combustor basket
Data Source
AI summary
A combustor (10) according to the invention includes: a combustor basket (14) in which compressed air and fuel are mixed with each other and the mixture is combusted; a transition piece (17) in which a tip portion of the combustor basket (14) is inserted with a gap (C) therebetween; a spring clip (19) that seals the gap between the combustor basket (14) and the transition piece (17); a throttle section (21) that is provided in an opening portion (Ck) of the gap (C) that is opened to the transition piece (17) on the tip side of the combustor basket (14), and narrows an opening area of the opening portion (Ck), compared to the base end side; and cooling device (22) for cooling the throttle section (21).