Gas Turbine Test Blade Root Slot for Controlled Blade-Off Release

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Solution Overview

Problem

Existing gas turbine engines lack a reliable method to predictably simulate blade detachment during a blade-off event, which can cause significant damage if not addressed.

Innovation Solution

A test blade design featuring an elongated opening in the root portion with a width at least three times the radial height, allowing controlled separation of the blade-off segment for predictable testing conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional blade root design is used, then the blade structure is simple and easy to manufacture, but the blade separation during testing is unpredictable and cannot provide reliable test data

Engineering Contradiction:
Improvepredictability of blade separationVSAvoidblade root structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The blade root is divided into multiple segments with distinct functional zones: a platform portion for mounting, a neck portion containing the elongated opening for controlled separation, and laterally extending portions for structural support. This segmentation allows the neck portion to be designed as a dedicated separation zone with specific geometric features (elongated opening with width ≥ 3 times radial height) that enable predictable blade detachment during testing, while the other portions maintain structural integrity and support functions.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If the blade root is made stronger to prevent detachment, then blade retention is improved, but controlled separation for testing becomes difficult to achieve

Engineering Contradiction:
Improvecontrolled separation capabilityVSAvoidblade root strength
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

Different regions of the blade root are assigned different structural properties: the platform and laterally extending portions are designed with high strength to ensure secure mounting and structural support, while the neck portion contains an elongated opening that creates a localized weak zone. This local quality differentiation allows the blade root to be strong where needed for retention while having a specific controlled weakness that enables predictable separation during testing when separation forces are applied.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4439036B1Test blade for gas turbine engine and method of making
Publication Date: 2025.11.12 PRATT & WHITNEY CANADA CORP
  • EP4439036B1 patent drawingFigure 1
  • EP4439036B1 patent drawingFigure 2
  • EP4439036B1 patent drawingFigure 3

AI summary

A test blade (74) for a blade release test, including: an airfoil (80) extending radially from a platform (82); and a root portion (96) secured to the platform (82), the root portion (96) having an elongated opening (100) extending longitudinally from a leading edge (102) of the root portion (96) towards a trailing edge (104) of the root portion (96), wherein the elongated opening (100) has a width (106) extending along the leading edge (102) of the root portion (96) that is greater than or equal to 3 times a radial height (108) of the elongated opening (100).