Gas Turbine Combustor Casing Projection Part
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Solution Overview
Problem
In gas turbines, the high-pressure and high-temperature compressed air flowing from the compressor to the combustor causes excessive thermal stress on the flanges joining the combustor and turbine casings, leading to increased fault generation and frequent part replacement due to low heat transfer coefficients around the flanges and high flow velocities.
Innovation Solution
A projection part is arranged on the inner face of the combustor casing, projecting radially inward to guide compressed air flow towards the inside, reducing thermal stress on the flanges by preventing heat transmission and improving assembly properties, and is designed with an inclined surface to smoothly separate compressed air and prevent turbulence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the pressure ratio of the compressor is increased to improve fuel efficiency, then the temperature of compressed air increases, but excessive thermal stress is applied to the flange causing increased fault generation and part replacement frequency
Solution Approach 1:
A projection part is introduced as an intermediary structure between the high-temperature compressed air flow and the flange. This projection part acts as a flow guide and thermal barrier, redirecting the compressed air away from the flange region and reducing direct thermal exposure, thereby protecting the flange from excessive thermal stress while allowing the compressor to operate at higher pressure ratios for improved fuel efficiency
Solution Approach 2:
The high-temperature compressed air that would normally cause harmful thermal stress on the flange is redirected by the projection part to flow along the inner face of the combustor casing away from the flange. The harmful thermal exposure is converted into a controlled flow pattern that maintains combustion efficiency while protecting the flange structure, effectively using the high-temperature flow's kinetic energy in a beneficial manner
2Reliability
If the projection part is arranged closer to the flange to better protect it, then thermal stress reduction is improved, but heat transmission to the flange increases
Solution Approach 1:
The projection part is strategically positioned in the axial direction to create local flow control zones. By placing it at a specific distance from the flange (not too close, not too far), the design creates a localized flow redirection zone that protects the flange from direct thermal exposure while preventing the projection part itself from becoming a heat conduction path to the flange
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 reduces thermal stress on the flanges, minimizing fault generation and part replacement frequency while enhancing assembly efficiency by guiding compressed air flow and preventing heat transmission to the flanges.
Implementation Method 1
the projection part functions as a dam for compressed air that spreads to the outside of the combustion chamber and flows along the inner face of the combustor casing, and guides the flow of the compressed air toward the inside in a radial direction
Implementation Method 2
a surface of the projection part facing the compressor has an inclined surface gradually inclined to the outside in the radial direction from the inner face of the combustor casing toward the turbine
Data Source
AI summary
A gas turbine includes a compressor, a combustor, and a turbine. The compressor, the combustor, and the turbine are arranged along an extending direction of a rotating shaft. The gas turbine also includes a combustor casing housing the combustor and a turbine casing housing the turbine. The combustor casing and the turbine casing are joined to each other via respective flanges thereof projecting toward the outside. The gas turbine further includes a projection part on an inner face of the combustor casing. The projection part projects toward the inside in a radial direction in at least part of a range in the extending direction of the rotating shaft between the flanges and an end of a combustion chamber on the compressor side in the combustor.