Turbine Blade Cooling Flow Adjustment via Thermal Expansion Plate
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Solution Overview
Problem
High-pressure turbine blades in airplane turbojets face excessive cooling air flow rate during takeoff and climbing, leading to reduced lifespan, while cruising stage requires reduced flow rate to increase efficiency, but existing methods fail to adjust cooling air flow passively and efficiently across varying engine speeds.
Innovation Solution
A turbine blade design featuring an adjustment plate with holes, made of material with a different coefficient of expansion than the blade root, allowing for passive adjustment of cooling air flow rate based on temperature differences, using thermal expansion to vary the flow section.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If cooling air flow rate is increased to protect blade lifespan during takeoff and climbing, then blade temperature is reduced and lifespan is extended, but turbojet efficiency decreases and specific fuel consumption increases
Solution Approach 1:
The patent applies dynamics by making the cooling air flow rate variable rather than constant. The adjustment plate moves passively in response to temperature changes, automatically increasing cooling flow during high-temperature phases (takeoff and climbing) to protect blade lifespan, and reducing cooling flow during lower-temperature phases (cruising) to improve fuel efficiency. This dynamic adjustment resolves the contradiction between blade protection and energy efficiency.
Solution Approach 2:
The patent changes the parameter of cooling air flow rate based on operating conditions. By using the adjustment plate mechanism, the flow rate parameter is modified automatically according to temperature variations during different flight stages, allowing optimal balance between blade temperature control and fuel consumption across the entire operating range.
2Loss of energy
If cooling air flow rate is reduced during cruising to improve turbojet efficiency, then specific fuel consumption decreases, but blade temperature increases and lifespan is shortened
Solution Approach 1:
The dynamic adjustment mechanism allows the system to adapt cooling flow to actual thermal conditions. During cruising, when blade temperatures are lower, the adjustment plate passively reduces the cooling flow area, decreasing specific fuel consumption while maintaining blade temperatures within acceptable limits through automated response to temperature changes.
Solution Approach 2:
The adjustment plate operates passively without external control, using the temperature differences themselves as the driving force. The system serves itself by automatically adjusting cooling flow based on its own thermal state, reducing fuel consumption during cruising while still protecting blade lifespan through self-regulated temperature management.
3Temperature
If constant cooling air flow rate is used across all operating stages, then blade temperature is controlled during takeoff and climbing, but turbojet efficiency is reduced during cruising due to excessive cooling
Solution Approach 1:
The patent transforms the static cooling system into a dynamic one where the adjustment plate automatically modifies the cooling flow area based on operating conditions. During takeoff and climbing, the plate position maintains adequate cooling for temperature control, while during cruising, it reduces cooling flow to optimize turbojet efficiency, eliminating the need for constant excessive cooling.
Solution Approach 2:
The adjustment plate creates local variation in cooling flow characteristics. By modifying the flow area at the inlet to the cooling cavities, it applies different cooling intensity locally according to the operational phase, allowing optimal temperature control during critical phases while improving overall efficiency during cruising.
4Productivity
If external control systems are used to adjust cooling air flow rate, then flow rate can be optimized for different operating stages, but device complexity increases and passive automatic adjustment is lost
Solution Approach 1:
The adjustment plate is designed to operate passively without external control systems. It uses the temperature differences between the blade and the plate itself as the driving force for automatic adjustment, eliminating the need for sensors, actuators, or control electronics while still achieving optimized cooling flow rates for different operating stages.
Solution Approach 2:
The patent replaces complex mechanical or electronic control systems with a simple thermal-mechanical mechanism. The adjustment plate's position is determined automatically by thermal expansion and contraction driven by temperature differences, substituting sophisticated control systems with a passive thermal response mechanism that achieves the same optimization goal with minimal complexity.
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 allows for reduced cooling air flow during cruising, enhancing turbojet efficiency and extending blade lifespan by minimizing temperature increase during takeoff and climbing stages, while maintaining prescribed blade lifetime.
Implementation Method 1
the adjustment plate is made of a material having a coefficient of expansion different from the coefficient of expansion of the material constituting the blade root, and in that the adjustment plate is mounted under the blade root with longitudinal guidance and is fastened in a manner that conserves the possibility of relative movement between the holes in the adjustment plate and the orifices in the blade root such that the fluid flow section increases with temperature
Data Source
AI summary
A turbine blade cooled by an automatically variable internal flow of cooling fluid. The blade includes orifices situated under the blade root via which the cooling fluid penetrates, and an adjustment plate including holes situated in register with the orifices, the adjustment plate having a coefficient of expansion that is different from the coefficient of expansion of the blade root.