Removing Fan Blade Leading Edge Shields With Pressurized Water Jets
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Solution Overview
Problem
Existing methods for removing metal attack edges from composite material blades in turbomachines often damage the fibers of the composite material, and require complex and costly machining processes.
Innovation Solution
A process using a high-pressure water jet to remove the metal attack edge shield from the blower dawn, where the thickness of the shield is determined through ultrasound and the water jet is adjusted accordingly to minimize damage to the composite material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If mechanical or thermomechanical tearing is used to remove the metal leading edge, then the leading edge can be removed from the blade, but the fibers of the composite material of the blade are damaged
Solution Approach 1:
The patent replaces mechanical tearing and conventional machining methods with a pressurized water jet system. The water jet, equipped with specialized nozzles and controlled pressure (100-1000 bars), removes the metal leading edge through hydraulic pressure and erosion without mechanical contact that would damage the composite blade fibers. This substitution of mechanical removal systems with a hydraulic system resolves the contradiction by enabling leading edge removal while preserving blade integrity.
Solution Approach 2:
The patent introduces water as an intermediary medium between the removal tool and the metal leading edge. The pressurized water jet acts as a mediator that transfers energy to remove the metal shield without direct mechanical contact with the composite blade. The water jet serves as a non-contact intermediary that enables material removal while protecting the underlying blade structure from damage.
2Ease of repair
If conventional machining solutions are used to remove the leading edge, then the leading edge can be removed, but complex devices and computer tools are required due to the awkward shape of the blade surface
Solution Approach 1:
The patent replaces complex mechanical machining devices with a pressurized water jet system. The water jet, delivered through relatively simple nozzles that can be manually or robotically positioned, eliminates the need for complex computer-controlled machining centers, multi-axis tooling, and sophisticated fixtures required for conventional machining of the complex blade geometry. This substitution dramatically reduces device complexity while maintaining removal effectiveness.
Solution Approach 2:
The patent employs a hydraulic system (pressurized water jet) to achieve material removal that would otherwise require complex mechanical machining equipment. The water jet system uses hydraulic pressure and flow dynamics to access and remove material from complex geometries without requiring the complex mechanical tooling and positioning systems needed for conventional machining of awkward-shaped blade surfaces.
3Ease of manufacture
If high pressure water jet is used to remove the leading edge shield, then the material removal process is simplified and blade damage is minimized, but the thickness of the shield must be determined beforehand
Solution Approach 1:
The patent performs preliminary thickness measurement of the metal leading edge shield using ultrasonic testing or other non-contact methods before initiating the water jet removal process. This preliminary action provides the necessary information to calculate the appropriate water jet pressure and duration parameters, enabling the simplified removal process to proceed effectively. The measurement step, while requiring equipment, is a one-time preparation that enables subsequent straightforward execution.
Solution Approach 2:
The patent employs feedback mechanisms where the measured thickness data is used to adjust and optimize the water jet parameters (pressure, flow rate, duration) for the removal process. This feedback loop ensures that the removal process is tailored to the specific shield thickness, maintaining process simplicity and effectiveness while adapting to variations in shield geometry and material properties.
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
The process effectively removes the metal attack edge without damaging the composite material, simplifies the material removal process for complex shapes, and reduces the risk of degrading the blower dawn material.
Implementation Method 1
Removing the leading edge shield by means of a pressurized water jet moving over the leading edge shield as a function of the thicknesses determined in the determining step
Implementation Method 2
Determining the thicknesses of the leading edge shield as a function of the position on the leading edge shield
Data Source
Figure 1~2
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AI summary
Disclosed is a method for removing a leading edge (5) attached to a fan blade (4), the fan blade (4) comprising a first material, and the leading edge (5) comprising a second material different from the first material, the method comprising the steps of determining thicknesses of the leading edge (5) as a function of the position on the leading edge (5), and of removing the leading edge (5) by means of a pressurised water jet (J) moving over the leading-edge (5) according to the thicknesses determined in the determination step.