Turbine Casing Cooling Air Supply Unit for Deformation Prevention
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Solution Overview
Problem
Existing gas turbine designs face deformation issues due to metal temperature differences between the upper and lower parts of the turbine casing when fuel supply is stopped, leading to the 'cat-back' phenomenon, which can cause rotor-stationary body contact and operational hazards.
Innovation Solution
A cooling air supply unit is implemented with a first supply unit facing the radially outer side of combustors and a second supply unit facing the radially inner side, ensuring sufficient cooling air reaches both regions to reduce metal temperature differences and prevent deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single purging device is arranged in the first region (radially outer side of combustors), then the device structure is simple, but the cooling air cannot reach the second region (radially inner side of combustors) sufficiently, reducing the effectiveness of suppressing metal temperature difference
Solution Approach 1:
The purging device is divided into two separate supply units: a first supply unit arranged in the first region (radially outer side of combustors) and a second supply unit arranged in the second region (radially inner side of combustors). This segmentation allows each unit to independently supply cooling air to its respective region, ensuring that the second region receives sufficient cooling air that would otherwise be blocked by the combustors, while maintaining overall system effectiveness.
2Device complexity
If cooling air is supplied only to the first region, then the device complexity is reduced, but the metal temperature difference between upper and lower parts of the casing cannot be sufficiently reduced due to the stagnant part in the second region
Solution Approach 1:
The cooling air supply system is segmented into two independent supply units positioned in different radial regions. The first supply unit supplies cooling air to the first region (radially outer side), while the second supply unit supplies cooling air to the second region (radially inner side). This segmentation ensures comprehensive cooling coverage across the entire casing interior, effectively reducing the metal temperature difference between upper and lower parts by addressing both the first region and the previously underserved second region.
3Ease of operation
If the purging device is arranged in the first region, then the ease of operation is improved, but the stagnation part in the second region remains unserved, reducing the overall purging effectiveness
Solution Approach 1:
The purging function is segmented between two supply units located in different radial regions. The first supply unit in the first region (radially outer side) handles cooling for the outer region, while the second supply unit in the second region (radially inner side) handles cooling for the inner stagnant region. This segmentation ensures that both regions are independently and effectively purged, with the second supply unit specifically addressing the previously unserved stagnation part.
Solution Approach 2:
The second supply unit acts as an intermediary element that bridges the cooling air supply to the second region (radially inner side of combustors), which is separated from the first supply unit by the combustors themselves. This intermediary supply unit ensures that cooling air reaches the stagnant part in the second region that would otherwise be inaccessible, thereby improving overall purging effectiveness.
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 metal temperature differences between the upper and lower casing parts, preventing deformation and potential rotor-stationary body contact, thereby enhancing operational safety and efficiency.
Implementation Method 1
the upper part of the casing with a higher temperature expands relative to the lower part of the casing with a lower temperature, and the casing deforms like a cat's back
Implementation Method 2
a cooling air supply unit configured to supply cooling air to an interior space of a casing
Data Source
AI summary
According to an embodiment, a turbine casing comprises a cooling air supply unit configured to supply a cooling air to an interior space of a casing of a gas turbine, and the cooling air supply unit includes: a first supply unit disposed in an upper half of the casing so as to face a first region and configured to supply the cooling air to the first region, where the first region is a region on a radially outer side of a plurality of combustors arranged annularly around a rotor; and a second supply unit disposed so as to face a second region and configured to supply the cooling air to the second region, where the second region is a region on a radially inner side of the plurality of combustors.