Turbine Stator Blade Clocking for Cooling Air Injection

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Solution Overview

Problem

Conventional gas turbine engines inefficiently utilize cooling air to reduce thermal loads on turbine airfoils, leading to reduced engine efficiency and material limitations due to high firing temperatures.

Innovation Solution

The circumferential positioning of stator blades is optimized relative to cooling air injection ports, allowing the cooling air to effectively cool the blades and minimize the amount of cooling air bled from the compressor, thereby enhancing turbine efficiency and allowing the use of less expensive materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If cooling air is extracted from the compressor and passed through cooling channels in turbine airfoils, then thermal load on airfoils is reduced, but engine efficiency decreases due to loss of cooling air in the main flow

Engineering Contradiction:

Improvethermal load on turbine airfoilsVSAvoidengine efficiency

Core Design Contradiction:

TemperatureVSLoss of energy

Solution Approach 1:

The invention extracts cooling air from the compressor discharge and directs it through cooling channels formed within the turbine airfoils, separating the cooling function from the main gas flow path. This allows targeted cooling of hot sections while minimizing interference with the primary combustion and power generation processes.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Cooling air acts as an intermediary substance that is introduced into the turbine airfoil structure, absorbs heat through thermal conduction and convection within the cooling channels, and then dissipates the absorbed heat to the surrounding environment, thereby protecting the airfoil from excessive thermal loads.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If more cooling air is used to cool turbine airfoils, then thermal stresses on airfoils are reduced, but the amount of cooling air bled from compressor increases

Engineering Contradiction:

Improveairfoil durabilityVSAvoidcooling air consumption

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The invention implements localized cooling by forming cooling channels within specific regions of the turbine airfoils that are subjected to highest thermal loads. This concentrates cooling resources where most needed, rather than uniformly cooling entire airfoil structures, thereby reducing total cooling air consumption while maintaining airfoil durability.

Inventive Principle:

Principle #3Local quality

3Power

If higher firing temperatures are used to increase engine efficiency, then power output improves, but material limitations prevent construction of more efficient engines

Engineering Contradiction:

Improveengine power outputVSAvoidmaterial temperature resistance

Core Design Contradiction:

PowerVSStrength

Solution Approach 1:

The invention converts the harmful effect of high firing temperatures, which normally would damage airfoil materials, into a beneficial situation by introducing cooling air that absorbs excess heat. The high temperatures that would otherwise be destructive are now harnessed to drive more efficient combustion while the cooling system manages the thermal loads, enabling higher power output without material failure.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 reduces thermal stresses on turbine stator blades, extends their lifespan, minimizes the need for cooling air circulation, and enables the design of engines with higher firing temperatures without new material advances, leading to increased efficiency and cost-effectiveness.

Implementation Method 1

cooling air is extracted from the compressor and passed through cooling channels that are formed within the rotor and stator blades

Methodology Applied

Scientific EffectHeat transfer through cooling channels: Conduction (thermal)

Implementation Method 2

the cooling air has a negative impact on the efficiency of the engine

Methodology Applied

Scientific EffectConvection cooling: Convection

Implementation Method 3

a plurality of circumferentially spaced injection ports disposed upstream of a first row of stator blades in the turbine; the injection ports comprising a port through which cooling air is injected into the hot-gas path of the turbine

Methodology Applied

Scientific EffectForced convection: Forced Convection

Data Source

PatentUS8087253B2Methods, apparatus and systems concerning the circumferential clocking of turbine airfoils in relation to combustor cans and the flow of cooling air through the turbine hot gas flowpath

Publication Date: 2012.01.03 GE INFRASTRUCTURE TECH LLC

AI summary

A method of operating a turbine engine, wherein the turbine engine includes a compressor, a combustor, a turbine, a plurality of successive axially stacked stages that include a row of circumferentially spaced stator blades and circumferentially spaced rotor blades, and a plurality of circumferentially spaced injection ports disposed upstream of a first row of stator blades in the turbine; the injection ports comprising a port through which cooling air is injected into the hot-gas path of the turbine, the method comprising: configuring the stator blades in the first row of stator blades such that the circumferential position of a leading edge of one of the stator blades is located within +/−15% pitch of the first row of stator blades of the circumferential location of the injection port midpoint of at least a plurality of the injection ports.