Turbine Blade Tip Cooling Slot Film Distribution

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Solution Overview

Problem

Turbine blade tips in gas turbine engines face challenges in cooling due to thermal barrier coatings being prone to removal from tight clearances with blade outer air seals, leading to increased heat loads and detrimental leakage airflows.

Innovation Solution

The implementation of cooling slots defined by merging diffuser portions from cooling holes, which provide a more efficient cooling film on the blade tip, reducing heat loads and preventing leakage airflow issues, while maintaining structural integrity and avoiding coating abrasion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If thermal barrier coatings are applied to turbine blade tips, then heat protection is improved, but the coating is removed due to rubbing with blade outer air seals

Engineering Contradiction:
Improvetip temperature protectionVSAvoidcoating retention
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent removes the thermal barrier coating from the blade tip region where rubbing occurs, extracting the coating only from the problematic area while maintaining it in other regions. This allows the blade to operate without coating damage at the tip while preserving thermal protection elsewhere.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies thermal barrier coating selectively to specific regions of the blade, maintaining coating quality in areas that do not experience rubbing while leaving the tip region uncoated or differently coated to avoid abrasion damage from contact with blade outer air seals.

Inventive Principle:
Principle #3Local quality

2Productivity

If tight clearances are designed between blade and BOAS, then aerodynamic performance is improved, but coating removal occurs due to rubbing

Engineering Contradiction:
Improveaerodynamic performanceVSAvoidcoating durability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The thermal barrier coating is extracted or removed from the blade tip region where contact with BOAS occurs, eliminating the coating durability issue while maintaining the tight clearance design for optimal aerodynamic performance.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The coating application is made local and selective, preserving coating quality in non-contact regions while excluding the tip region from coating to prevent rubbing damage, thereby maintaining both aerodynamic performance and coating durability.

Inventive Principle:
Principle #3Local quality

3Temperature

If cooling slots are added to reduce tip heat load, then thermal management is improved, but device complexity increases

Engineering Contradiction:
Improvetip heat loadVSAvoidcooling system complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The cooling system is segmented into multiple discrete cooling slots distributed across the blade surface, each fed by separate cooling holes. This segmentation allows for modular implementation and maintenance while effectively distributing cooling flow to manage tip heat loads.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple cooling holes are merged into a common cooling slot structure, where individual cooling holes feed into a shared slot that distributes coolant across the tip region. This merging approach reduces overall system complexity compared to having separate cooling channels for each location.

Inventive Principle:
Principle #5Merging (Combining)

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 solution effectively reduces tip temperatures and improves cooling film effectiveness, minimizing gaps for hot air to contact the blade, thus enhancing the thermal management of turbine blades and preventing coating removal.

Implementation Method 1

a tip cooling slot formed by merging diffuser portions of cooling holes

Methodology Applied
Scientific EffectFilm cooling: Convection

Implementation Method 2

providing cooling fluid to the at least one cooling slot

Methodology Applied
Scientific EffectFluid flow: Convection

Data Source

PatentEP3354853B1Turbine blade with slot film cooling and manufacturing method
Publication Date: 2021.05.19 RTX CORP
  • EP3354853B1 patent drawingFigure 1
  • EP3354853B1 patent drawingFigure 2
  • EP3354853B1 patent drawingFigure 3A~3C

AI summary

A component for a gas turbine engine (20), the component having: a cooling slot located on a surface of the component, the cooling slot being defined by a plurality of diffuser portions (88) each extending from a respective one of a plurality of cooling openings providing cooling fluid to the cooling slot.