Crossfire Tube Cooling Guide Ring Angled Holes
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Solution Overview
Problem
The crossfire tube assembly in multi-can type gas turbines is exposed to high-temperature combustion exhaust gas, leading to thermal deformation and fire damage, as existing cooling methods either lower the combustion exhaust gas temperature during ignition or increase machining costs due to limited cooling range and complex positioning requirements.
Innovation Solution
The crossfire tube assembly is configured with air holes drilled towards the closed end side and a guide ring with an annular space, allowing for enhanced cooling through impingement effect expansion, and optionally using an obstacle to direct air flow, facilitating cooling with a smaller air amount without lowering combustion exhaust gas temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cooling air is introduced into the crossfire tube assembly to prevent thermal deformation and fire damage, then the crossfire tube assembly is protected from thermal damage, but the temperature of the combustion exhaust gas during ignition is lowered
Solution Approach 1:
The cooling air holes are segmented into two groups with different orientations: some holes drill toward the open end side while others drill toward the closed end side. This segmentation allows cooling air to be distributed to different regions of the guide ring, enabling comprehensive cooling of the guide ring outer circumferential surface without requiring excessive cooling air that would lower combustion exhaust gas temperature.
Solution Approach 2:
Different regions of the guide ring receive cooling air from different directions based on their thermal exposure characteristics. The air holes directed toward the open end side cool regions exposed to combustion exhaust gas from that direction, while air holes directed toward the closed end side cool regions near the closed end. This local quality approach optimizes cooling efficiency and reduces the total cooling air requirement.
2Reliability
If air holes are provided in the inner tube to cool the crossfire tube assembly, then thermal deformation is prevented, but the positioning and machining complexity increases
Solution Approach 1:
The guide ring serves multiple functions: it positions the air holes in the inner tube, it cools the crossfire tube assembly through the air holes, and it provides structural support. By making the guide ring multi-functional, the design reduces the need for separate positioning features and simplifies the overall manufacturing process despite the complex air hole configuration.
Solution Approach 2:
The guide ring is provided in advance as a positioning feature during the design phase. The air holes are positioned relative to the guide ring, which simplifies machining operations. The guide ring pre-establishes the geometric relationships needed for the air holes, reducing the complexity of direct machining of the inner tube.
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 configuration effectively cools the crossfire tube assembly, preventing thermal deformation and fire damage while maintaining combustion exhaust gas temperature during ignition, and reduces machining complexity and costs.
Implementation Method 1
a current of air flowing in from the air holes flows along the inner circumferential wall surface of the inner tube from the open end face of the guide ring
Implementation Method 2
enhanced cooling through impingement effect expansion
Data Source
AI summary
The present invention provides a multi-can type gas turbine combustor including a plurality of combustors that mix and burn fuel and the air, the combustors being connected by a crossfire tube assembly. The gas turbine cools the crossfire tube assembly without lowering the temperature of a combustion exhaust gas passing through the crossfire tube assembly and prevents thermal deformation and fire damage of the crossfire tube assembly. In a gas turbine according to the present invention, a guide ring that guides a current of the air is provided in a position opposed to air holes. One side end portion of an annular space configured between the guide ring and a crossfire tube assembly is opened to a space on the inside of the crossfire tube assembly. The other end portion is a closed end connected to a partition wall configuring the crossfire tube assembly. The length of an annular space between the air holes and the closed end is set to three times or more as large as the diameter of the air holes. Further, a part of the air holes is drilled to tilt to the closed end of the annular space to cool the crossfire tube assembly including the guide ring with a small cooling air amount.