Gas Turbine Swirled Cooling Air Inlet Angle Control
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Solution Overview
Problem
Gas turbine engines face windage power loss and thermal response issues due to the delivery of cooling air, which affects power transmission and tip clearances, with existing methods either increasing or decreasing heat transfer coefficients and tip clearance responses.
Innovation Solution
A gas turbine engine design that allows for the variation of inlet swirl angle of cooling air through a plurality of air entry nozzles, using a cooling air supply arrangement to switch between different swirl angles based on operating conditions, optimizing windage power loss and thermal transient responses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If cooling air is delivered with significant swirl angle in the direction of rotor rotation, then windage power loss is reduced, but heat transfer coefficients on the disc face are reduced leading to slower thermal response
Solution Approach 1:
The patent applies dynamics by making the swirl angle adjustable rather than fixed. The cooling air delivery system can vary the inlet swirl angle between different operating conditions, allowing optimization of windage power loss during steady-state operation and thermal response speed during transient conditions. This dynamic adjustment resolves the contradiction between reducing energy loss and maintaining thermal response capability.
Solution Approach 2:
The patent changes the parameter of inlet swirl angle to resolve the technical contradiction. By varying this parameter between different values depending on whether the engine is in steady-state or transient operation, the system can simultaneously achieve reduced windage power loss and maintained heat transfer coefficients, thus resolving the contradiction between energy loss reduction and thermal response speed.
2Temperature
If cooling air is delivered axially without swirl, then heat transfer coefficients are maintained, but windage power loss increases reducing power transmission
Solution Approach 1:
The system dynamically adjusts the swirl angle based on operating conditions. During steady-state operation where thermal response is less critical, a higher swirl angle is used to reduce windage power loss. During transient conditions where thermal response is critical, the swirl angle is reduced to maintain heat transfer coefficients. This dynamic adaptation resolves the contradiction between maintaining temperature control and reducing energy loss.
Solution Approach 2:
The inlet swirl angle parameter is varied between different values to resolve the contradiction. When thermal response is prioritized, a lower swirl angle maintains heat transfer coefficients. When energy efficiency is prioritized, a higher swirl angle reduces windage power loss. This parameter variation allows the system to resolve the technical contradiction between temperature control and energy loss.
3Speed
If higher heat transfer coefficients are achieved, then disc thermal response is speeded up, but this may affect transient pinch point closures and blade tip clearance rubs
Solution Approach 1:
The system dynamically controls the swirl angle to achieve appropriate thermal response speed for different operating conditions. By adjusting the swirl angle, the system can speed up thermal response when needed while avoiding excessive HTC increases that would cause pinch point closure issues. This dynamic control resolves the contradiction between thermal response speed and clearance stability.
Solution Approach 2:
The inlet swirl angle parameter is adjusted to optimize the balance between heat transfer coefficients and thermal response. By changing this parameter, the system achieves sufficient thermal response speed without creating excessively high HTCs that would lead to pinch point closure and clearance rub problems, thus resolving the contradiction between response speed and reliability.
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 approach reduces windage power loss and improves both transient and steady-state tip clearances by optimizing the swirl angle for different engine operating conditions, enhancing the engine's performance and thermal management.
Implementation Method 1
the delivery of cooling air C to the cavity 27 at an inlet swirl angle which can be varied between a first inlet swirl angle and a different second inlet swirl angle
Data Source
AI summary
A gas turbine engine has in flow series a compressor section, a combustor, and a turbine section. The engine includes a turbine section rotor disc, and a stationary wall forward of a front face or rearward of a rear face of the rotor disc. The wall defines a cavity between the stationary wall and the rotor disc, and has a plurality of air entry nozzles through which cooling air can be delivered into the cavity at an inlet swirl angle. The engine further includes a cooling air supply arrangement which accepts a flow of compressed air and supplies the compressed air to the nozzles for delivery into the cavity. The cooling air supply arrangement and the nozzles are configured such that the inlet swirl angle of the air delivered into the cavity can be varied between a first inlet swirl angle and a second inlet swirl angle.