Turbine Blade Tip Cooling via Flow Accelerator
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Solution Overview
Problem
Gas turbine engine rotor blades face challenges in cooling, particularly at the blade tips, due to high temperatures, which can lead to overheating and reduce the useful life of components.
Innovation Solution
The implementation of a turbine rotor blade with an internal cooling circuit and a flow accelerator within the tip cap passage to accelerate cooling air, enhancing convection and conduction cooling, and allowing for more effective film cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling air is delivered through internal passages to rotor blades, then blade temperature is reduced, but pressure losses increase and cooling effectiveness at blade tips remains insufficient
Solution Approach 1:
The patent applies local quality by delivering cooling air directly to the blade tip region through a dedicated tip cap passage, rather than using a uniform cooling approach throughout the blade. The flow accelerator is specifically positioned within the tip cap passage to concentrate cooling effectiveness at the most critical thermal zone (blade tip), while the throttling projection allows pressure regulation to minimize overall pressure losses in the cooling system.
Solution Approach 2:
The patent employs parameter changes by using a throttling projection that can be inserted to different extents into the tip cap passage, thereby dynamically adjusting the cooling air flow rate and pressure. This allows optimization of the balance between cooling effectiveness and pressure loss by varying the opening area of the passage, adapting to different operating conditions.
2Reliability
If cooling air flow is increased at blade tips, then cooling effectiveness is improved, but pressure losses increase
Solution Approach 1:
The throttling projection mechanism provides a form of feedback control where the degree of insertion can be adjusted based on operating conditions to maintain optimal cooling effectiveness while minimizing pressure losses. The design allows for optimization of the cooling air flow rate to match actual thermal demands at the blade tip.
Solution Approach 2:
The flow accelerator creates a localized region of accelerated flow that concentrates cooling effectiveness precisely where needed at the blade tip, rather than distributing cooling uniformly throughout the entire blade. This partial action approach delivers excessive cooling locally at the tip region while avoiding unnecessary pressure losses in other areas.
3Power
If engine operating temperature is increased, then power output is improved, but blade overheating and mechanical issues occur
Solution Approach 1:
The patent implements preliminary action by pre-cooling the blade tip region through the internal tip cap passage before the blade material reaches critical temperatures. The cooling system is designed to proactively manage heat accumulation at the blade tip, preventing thermal damage before it occurs and enabling sustained operation at higher engine temperatures.
Solution Approach 2:
The cooling air acts as an intermediary substance that transfers heat away from the blade tip region. The flow accelerator and tip cap passage system mediate between the hot blade material and the cooler ambient environment, enabling the blade to withstand higher operating temperatures by providing a controlled thermal management interface.
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 solution improves cooling efficiency at the blade tips, allowing for increased engine temperature operation, reduced fuel consumption, and extended service life while minimizing pressure losses and enhancing film cooling effectiveness.
Implementation Method 1
accelerate cooling air, enhancing convection and conduction cooling
Implementation Method 2
accelerate cooling air, enhancing convection and conduction cooling
Data Source
AI summary
A turbine rotor blade for a turbine section of an engine is provided. The rotor blade includes a platform and an airfoil extending from the platform into a mainstream gas path of the turbine section. The airfoil includes a pressure side wall, a suction side wall joined to the pressure side wall at a leading edge and a trailing edge, and a tip cap extending between the suction side wall and the pressure side wall. The rotor blade further includes an internal cooling circuit having a tip cap passage configured to deliver cooling air to the tip cap and a flow accelerator positioned within the tip cap passage of the internal cooling circuit.