Bifurcation Panel Tip Clearance Control for Gas Turbine Engines
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Solution Overview
Problem
Gas turbine engines face efficiency reduction due to differential thermal expansion of components, leading to varying tip clearance between turbine blades and shrouds, which can result in leakage and component damage, and existing tip clearance control systems often compromise engine efficiency.
Innovation Solution
A gas turbine engine with a tip clearance control system that includes a bifurcation panel with an inlet on its first major surface, closer to the trailing edge, allowing air to be directed onto the turbine casing to control the gap between blades and shroud, utilizing bypass flow and potentially cooler air to manage thermal expansion and contraction effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If air is supplied to the turbine casing to control thermal expansion and maintain tip clearance, then the gap between turbine blades and casing can be controlled, but engine efficiency is compromised
Solution Approach 1:
The system changes the temperature parameter of air supplied to the turbine casing to control thermal expansion. By adjusting air temperature, the casing expands or contracts radially to maintain optimal tip clearance, resolving the contradiction between reliable clearance control and energy loss through precise parameter management
Solution Approach 2:
The tip clearance control system uses air already present within the engine core, allowing the system to serve itself by utilizing internal resources. This self-service approach minimizes additional energy input requirements while maintaining effective clearance control through intelligent use of existing thermal and pressure conditions
2Reliability
If air supply temperature is increased to encourage thermal expansion of the casing, then tip clearance control is improved, but more energy is consumed
Solution Approach 1:
The system dynamically adjusts the temperature parameter of supply air based on operating conditions. By changing temperature parameters appropriately, the system achieves effective tip clearance control while optimizing energy consumption, avoiding excessive energy use through precise parameter management
Solution Approach 2:
The system applies partial thermal action by supplying air at temperatures sufficient to achieve the required degree of casing expansion for tip clearance control, rather than using excessive temperature that would waste energy. This partial action approach maintains effectiveness while minimizing energy consumption
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 enhances tip clearance control and reduces the impact on engine efficiency by providing improved driving pressure and temperature control, minimizing leakage and extending component life.
Implementation Method 1
differential thermal expansion of components. The turbine section of a gas turbine engine can reach particularly high temperatures as it is downstream of the combustor, such that the dimension of a clearance space between the tip of a turbine blade and a shroud may vary during use depending on the operating condition
Implementation Method 2
control the expansion and contraction of the turbine casing the introduction of an air supply at a temperature which encourages a desired amount of thermal expansion or contraction of the casing
Implementation Method 3
Leakage between the tip of a turbine blade and its shroud or casing can result in a significant reduction in the turbine's efficiency
Data Source
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AI summary
A tip clearance control (TCC) system 100 is provided to control the gap 176 between the tips of turbine blades 172 of a gas turbine engine 10 and the casing 174 within which they rotate. The inlet 120 to the TCC system is provided in a bifurcation panel 110 that extends across a bypass duct 22 of the gas turbine engine 10. The inlet is provided on a first major surface 112 of the bifurcation panel 110 that is defined such that the direction (R) that points through the bifurcation panel from the first major surface 112 to a second major surface 114 corresponds to the fan rotation direction. This provides a particularly effective and/or efficient TCC system 100.