Turbine Blade Tip Segmentation for Squealer Cooling
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Solution Overview
Problem
The squealer on turbine blades is prone to damage from high-temperature combustion gas due to insufficient cooling, especially at the trailing edge where space for cooling holes is limited, leading to potential energy loss and reduced thermal efficiency in gas turbines.
Innovation Solution
The design modifies the turbine blade by forming the squealer only from the leading edge to the starting end of the trailing edge region, with the trailing edge region being flush with the top plate and applying a heat-resistant coating on the entire top plate surface, ensuring the squealer is not exposed to high temperatures and minimizing the gap between the squealer and the ring segment to prevent damage and energy loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the squealer is extended to the trailing edge to minimize gap flow, then energy loss is reduced, but the squealer is exposed to high-temperature combustion gas and becomes damaged
Solution Approach 1:
The blade tip structure is segmented into three distinct regions: a top plate region, a squealer region extending from the leading edge to the trailing edge region, and a trailing edge region. This segmentation allows each region to have optimized characteristics - the top plate provides structural support, the squealer minimizes gap flow, and the trailing edge region protects against high-temperature exposure
Solution Approach 2:
Different regions of the blade tip are given different local qualities and functions. The top plate has a first upper surface, the squealer has a second upper surface with different thermal exposure characteristics, and the trailing edge region has a third upper surface with height lower than the second upper surface. This local differentiation allows the squealer to perform its damming function while the trailing edge region provides thermal protection
2Productivity
If the gap between the squealer and ring segment is made small to prevent combustion gas leakage, then thermal efficiency is improved, but manufacturing precision requirements increase
Solution Approach 1:
The blade tip structure incorporates dynamic adaptability through the differentiated height configuration of its regions. The trailing edge region has a height lower than the squealer region, creating a stepped configuration that dynamically adapts to operational conditions while maintaining the gap between the top plate and ring segment within a controlled range, thereby ensuring thermal efficiency without excessive manufacturing precision requirements
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 prevents squealer damage, reduces energy loss, and maintains thermal efficiency by ensuring adequate cooling and protection from high-temperature combustion gas, thereby enhancing the operational stability and efficiency of gas turbines.
Implementation Method 1
the top plate 17 and the squealer 23 are cooled by a cooling medium CA which flows through cooling holes 28a and 28b
Implementation Method 2
a heat-resistant coating (also referred to as TBC) 24 is applied on outside surfaces, such as the top plate 17 of the blade tip 15... thereby interrupting the heat from the high-temperature combustion gas
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
A turbine blade of the invention includes an air foil including a plurality of cooling flow passages through which a cooling medium flows from a leading edge region to a trailing edge region, a top plate which forms the apex of the air foil, has a heat-resistant coating applied on the upper surface thereof, and includes a plurality of cooling holes, and a squealer which protrudes radially outward from the blade from the top plate, and is formed so as to extend from a leading edge end to a starting end of the trailing edge region along a suction-surface-side blade wall in a peripheral direction of the blade.