Gas Turbine Test Blade Root Slot for Predictable Separation
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Solution Overview
Problem
Existing gas turbine engines lack a reliable method to simulate and evaluate the impact of blade detachment during operation, which can cause significant damage due to high-speed blade impacts.
Innovation Solution
A test blade design featuring an elongated opening or slot in the root portion, with a width at least three times the radial height, strategically positioned to facilitate predictable separation and simulate blade-off events for testing purposes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional solid root portion is used, then the blade structure is simple and strong, but the blade cannot be separated controllably for testing purposes
Solution Approach 1:
The root portion is segmented by introducing an elongated opening that divides the solid root structure into separate sections. This segmentation creates a controlled weak point that allows the blade to separate predictably during testing while maintaining the overall structural integrity when assembled. The opening effectively divides the root portion into multiple segments that can detach independently.
Solution Approach 2:
Material is extracted from the root portion by creating the elongated opening, removing the solid material in the region defined by the opening. This extraction creates a deliberate void that reduces the structural strength at that location, enabling controlled separation. The removed material volume is defined by the opening's dimensions, particularly its width extending along the leading edge.
2Reliability
If no opening is provided in the root portion, then the blade structure remains intact and simple, but blade-off impact damage cannot be evaluated
Solution Approach 1:
The elongated opening is created during the manufacturing process as a preliminary feature, preparing the blade for future separation and testing. This preliminary action embeds the separation capability into the blade structure during manufacturing, so that when the blade is installed and subjected to operational conditions, the separation can occur predictably without requiring additional modifications or complex assembly procedures.
3Reliability
If the opening width is small, then the blade structure remains strong, but predictable separation cannot be achieved
Solution Approach 1:
The width of the elongated opening is specifically designed to be at least 3 times the radial height of the opening, creating a specific geometric parameter relationship. This parameter change ensures that the opening is sufficiently wide to create a controlled separation path while maintaining appropriate structural strength when the blade is properly assembled. The specific width-to-height ratio optimizes the balance between separation capability and structural integrity.
Data Source
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AI summary
A test blade (74) designed in order to perform a predictable separation of the test blade during 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 slot (118) extending longitudinally on an exterior surface from a leading edge (102) of the root portion (96) towards a trailing edge (104) of the root portion (96), wherein the elongated slot (118) is located below the platform (82) and in a middle of a neck portion (114) of the root portion (96).