Blisk Fan Blade Release via Arc Passage Charge
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Solution Overview
Problem
Current methods for testing turbofan engines during fan blade off events are inadequate, particularly for blisk designs, as they lack precision and control in releasing the fan blade, which is essential for containment case validation and safety certifications.
Innovation Solution
A method involving an internal passage with a constant arc through the airfoil of a blisk, packed with a charge, allows for precise and controlled release of the fan blade by detonating the charge along the chordwise length, ensuring even detachment without breaching the sidewalls, and utilizing detonating cord or shape charge configurations for accurate timing and direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional drilling methods are used to release fan blades from blisks, then the release process is simpler, but the precision and control of blade detachment is insufficient
Solution Approach 1:
The internal passage is segmented into multiple sections along the chordwise length of the airfoil, with charge packing zones distributed throughout. This segmentation allows the explosive force to be applied at multiple points simultaneously, achieving uniform and precise detachment of the fan blade from the blisk while maintaining controlled complexity through modular charge placement
Solution Approach 2:
The passage follows a constant arc trajectory through the airfoil thickness rather than a straight line, aligning with the contour of the blisk. This curved three-dimensional path allows the charge to be positioned optimally throughout the bond line, achieving precise release control without requiring complex external positioning mechanisms
2Measurement precision
If explosives are used to cause fan blade separation, then the release can be achieved, but the control and timing precision is insufficient
Solution Approach 1:
The charge is distributed locally throughout multiple sections of the internal passage rather than concentrated in a single location. This local distribution of explosive material ensures that the release force is applied uniformly across the entire chordwise length of the airfoil, achieving precise timing and controlled detachment while minimizing harmful effects from uncontrolled explosion
Solution Approach 2:
The internal passage is pre-formed within the airfoil structure before the explosive charge is introduced. This preliminary preparation provides a predetermined, controlled path for the explosive force to follow, ensuring that when detonated, the release occurs with precise timing and controlled direction, minimizing damage from uncontrolled explosion
3Ease of manufacture
If the internal passage breaches sidewalls of the airfoil, then the charge can be easier to install, but the structural integrity is compromised
Solution Approach 1:
The internal passage is nested entirely within the airfoil structure, following a constant arc through the thickness without breaching the sidewalls. The passage is contained within the airfoil's material volume, and the charge is nested within the passage, achieving easy installation through the nested configuration while maintaining structural integrity by not compromising the external sidewall geometry
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
Enables precise and controlled release of the fan blade during testing, simulating fan blade off events with improved safety and accuracy, validating containment case performance and aiding in certifications by minimizing damage and ensuring structural integrity.
Implementation Method 1
detonating the charge such that the airfoil is released from the blisk at a selected time
Implementation Method 2
utilizing detonating cord or shape charge configurations for accurate timing and direction
Data Source
AI summary
According to one aspect, a method of releasing a fan blade for testing a turbofan engine includes providing an internal passage with a constant arc through an airfoil arranged about a blisk such that the constant arc of the internal passage aligns with a contour of the blisk. The method further includes packing the internal passage with a charge, modifying the airfoil such that the airfoil is released from the blisk evenly along a chordwise length of the airfoil, and detonating the charge such that the airfoil is released from the blisk at a selected time.