Vane-Blade Count Ratio Greater Than Unity in Gas Turbine Engines
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Solution Overview
Problem
High inlet temperature and chemical species non-uniformities at the exit of a combustor in gas turbine engines lead to compromised turbine durability, necessitating conservative cooling designs to prevent damage, which increases weight and reduces efficiency.
Innovation Solution
A gas turbine engine design with a higher number of vanes than blades in the turbine section, where the combustion reaction is completed before the blades, using cooling air to mix with combustion products and film-cooling the vanes, reduces temperature non-uniformities and cooling requirements, thereby enhancing mixing and aerodynamic efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conservative cooling designs are used to prevent turbine damage from temperature non-uniformities, then turbine durability is improved, but weight increases and efficiency decreases
Solution Approach 1:
The patent changes the geometric parameters of the turbine stage by using a vane count that is a multiple of the blade count (vane-blade count ratio greater than unity). This parameter change modifies the flow pattern and temperature distribution characteristics, allowing the turbine to handle temperature non-uniformities without requiring excessive cooling, thus reducing weight while maintaining durability
Solution Approach 2:
The patent introduces asymmetry in the vane-blade configuration where the number of vanes is deliberately made different from and a multiple of the number of blades. This asymmetric configuration creates specific flow interaction patterns that promote mixing and reduce temperature non-uniformities, eliminating the need for conservative cooling designs
2Reliability
If conservative cooling designs are used to prevent turbine damage from temperature non-uniformities, then turbine durability is improved, but efficiency decreases
Solution Approach 1:
By changing the vane-blade count ratio to greater than unity, the patent modifies the aerodynamic and thermal parameters of the turbine stage. This allows the turbine to operate efficiently without excessive cooling air requirements, reducing energy loss while maintaining durability against temperature non-uniformities
Solution Approach 2:
The patent converts the potentially harmful temperature non-uniformities and chemical species variations into beneficial mixing effects through the specific vane-blade configuration. The non-uniformities that would normally require conservative cooling are instead utilized to enhance mixing and complete combustion, improving efficiency while maintaining durability
3Power
If high fuel-to-air ratio combustion is used, then power output is improved, but temperature and chemical species non-uniformities increase
Solution Approach 1:
The patent changes the geometric parameters of the turbine stage (vane-blade count ratio) to specifically address the temperature non-uniformities created by high fuel-to-air ratio combustion. This parameter change enables the turbine to handle the resulting thermal conditions while maintaining the high power output benefits
4Power
If high fuel-to-air ratio combustion is used, then power output is improved, but turbine durability is compromised
Solution Approach 1:
By modifying the vane-blade count ratio to greater than unity, the patent creates a turbine stage configuration that is specifically suited for handling the temperature and chemical species non-uniformities resulting from high fuel-to-air ratio combustion, thereby maintaining turbine durability while preserving power output
Solution Approach 2:
The asymmetric vane-blade configuration promotes enhanced mixing and more uniform temperature distribution at the turbine inlet, allowing high fuel-to-air ratio combustion to be used without compromising turbine durability
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 design reduces the need for conservative cooling, leading to weight reduction, improved aerodynamic efficiency, and lower cooling air requirements, while effectively managing temperature and chemical species non-uniformities, thus enhancing the durability and performance of the turbine.
Implementation Method 1
mixing combustion products from the combustion section using the vanes of the first set of vanes
Implementation Method 2
using cooling air to mix with combustion products and film-cooling the vanes
Data Source
AI summary
An exemplary gas turbine engine includes a turbine section operative to impart rotational energy to a compressor section. The turbine section includes at least a low-pressure turbine and a high-pressure turbine, and a ratio of a number of stages in the low-pressure turbine to a number of stages in the high-pressure turbine is 2.