Cooled Turbine Blade Tip Shroud Plenum Segmentation
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Solution Overview
Problem
Turbine blade tip shrouds are subjected to high mechanical and aerodynamic stresses and temperatures, leading to reduced design life due to inadequate cooling methods.
Innovation Solution
A cooled turbine blade design featuring a core and peripheral plenum in the tip shroud, with separate cooling streams directed through airfoil passages to effectively transfer heat from the trailing edge and core sections, utilizing impingement cooling and venting to manage temperature and stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional cooling methods are used with integral tip shrouds, then the turbine blade can operate in high temperature environments, but the design life is reduced due to high mechanical and aerodynamic stresses and inadequate cooling
Solution Approach 1:
The cooling system is segmented into two separate plenums (core plenum and peripheral plenum) with distinct cooling streams. The peripheral plenum receives cooling fluid through the aft airfoil cooling passage, while the core plenum receives cooling fluid through core airfoil cooling passages. This segmentation allows differentiated cooling strategies for different regions of the tip shroud, optimizing both temperature control and stress management to extend design life.
Solution Approach 2:
Different regions of the tip shroud are provided with different cooling characteristics. The peripheral plenum with its aft airfoil cooling passage provides enhanced cooling at the trailing edge and peripheral regions, while the core plenum serves the central region. This local quality approach ensures that high-stress areas receive appropriate cooling intensity, improving durability without compromising temperature control.
2Power
If integral tip shrouds are incorporated to improve work extraction, then turbine performance is improved, but the tip shroud is subjected to high mechanical and aerodynamic stresses and high temperature environment
Solution Approach 1:
The invention uses pneumatic cooling by introducing cooling fluid through dedicated passages (aft airfoil cooling passage and core airfoil cooling passages) into separate plenums. This hydraulic/pneumatic system delivers pressurized cooling fluid directly to the tip shroud regions, providing active thermal management that enables the tip shroud to withstand high mechanical and aerodynamic stresses while maintaining structural strength.
Solution Approach 2:
The tip shroud structure incorporates integrated cooling passages and dual plenum chambers within the same component. This composite design combines the structural function (work extraction) with the thermal management function (cooling), creating a multi-functional element that maintains strength under stress while operating in high-temperature environments.
3Temperature
If cooling fluid is extracted from the compressor and passed directly to the turbine section, then the cooling fluid provides pressurized and relatively cool fluid for blade cooling, but the cooling efficiency for airfoil trailing edge and tip shroud is insufficient
Solution Approach 1:
The cooling fluid supply is segmented into two separate streams that are distributed to different plenums through dedicated passages. The aft airfoil cooling passage delivers cooling fluid to the peripheral plenum, while core airfoil cooling passages deliver cooling fluid to the core plenum. This segmentation improves cooling efficiency by directing cool fluid precisely to the regions that need it most, enhancing reliability of the cooling system.
Solution Approach 2:
The dual plenum structure acts as an intermediary system between the cooling fluid source and the tip shroud. The plenums distribute and regulate the cooling fluid flow to different regions, improving the effectiveness of the cooling process and ensuring reliable temperature control across the entire tip shroud structure.
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 design enhances the cooling efficiency of turbine blade tip shrouds, reducing material operating temperatures and increasing the useful life of the blade while allowing it to operate in hotter environments.
Implementation Method 1
The peripheral cooling stream is directed through an aft airfoil cooling passage extending radially through the airfoil proximate a trailing edge portion of the airfoil so as to transfer heat from the trailing edge portion of the airfoil to the peripheral cooling stream
Implementation Method 2
The core cooling stream is directed through one or more core airfoil cooling passages extending through a core section of the airfoil so as to transfer heat from the core section to the core cooling stream
Data Source
AI summary
A cooled turbine blade comprises a root for fixing the blade to rotor, an airfoil extending along a radial axis from the root, and a tip shroud disposed at a radially outward end of the airfoil. The tip shroud extends in a circumferential direction from the airfoil and defines, within itself, a core plenum and a peripheral plenum. The airfoil defines an aft airfoil cooling passage that extends radially through the airfoil proximate a trailing edge portion of the airfoil. The airfoil also defines an aft cooling inlet for providing an aft stream of cooling fluid to the aft airfoil cooling passage. The airfoil also defines at least one aft cooling exit for discharging the aft stream of cooling fluid from the aft airflow cooling passage to the peripheral plenum. The tip shroud defines at least one peripheral plenum vent for discharging the aft stream of cooling fluid.