Bladed Rotor Wheel Lock Retention via Upstream Rib Engagement
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Solution Overview
Problem
In turbomachines, particularly in the last stages of low-pressure compressors with conical blades, the risk of blade loosening due to oblique orientation and potential impact-induced deformation of the upstream annular lip leading to groove widening and lock ejection is a significant concern.
Innovation Solution
The modification of the lock shape includes an upstream rib engaging in a recessed part of the upstream annular cavity, ensuring the lock remains secured even if the groove widens, combined with relief notches and a tapped hole for screw placement to maintain the lock's position between blade roots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the upstream annular lip is deepened to accommodate voluminous blade heels, then blade retention capacity is improved, but the complexity of the groove structure increases
Solution Approach 1:
The upstream annular cavity is segmented into two distinct zones: a first part at the normal groove level and a second recessed part extending deeper. This segmentation allows the groove to accommodate voluminous blade heels while maintaining a structured and manageable design, resolving the contradiction between improved retention capacity and structural complexity.
2Stability of the object's composition
If locks are installed in the groove to prevent circumferential blade movement, then blade stability is improved, but the risk of lock ejection due to groove widening increases
Solution Approach 1:
The locking mechanism incorporates a proactive design where the lock engages with the blade root and groove structure in advance to prevent circumferential movement. The lock is positioned and secured before any potential incident occurs, ensuring that even if the groove widens due to impact, the blade cannot move circumferentially to a position where ejection could occur.
3Ease of operation
If the groove is widened to accommodate blade movement during assembly, then ease of blade installation is improved, but the risk of lock ejection during operation increases
Solution Approach 1:
The groove exhibits local quality variations: it is wider in the regions where blades are inserted to facilitate easy installation, but narrower in the regions where locks are positioned to prevent lock ejection. This localized differentiation of groove dimensions allows simultaneous achievement of easy assembly and secure lock retention during operation.
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 configuration ensures the lock remains securely engaged within the groove, preventing circumferential movement and ejection, even under stress conditions, thereby enhancing blade retention and preventing potential incidents.
Implementation Method 1
the base of each lock comprises an upstream rib, engaged during assembly in said recessed part
Implementation Method 2
the screw bears against the wall of the disk between the two lips and causes the lifting and the final positioning of the lock
Data Source
Figure 1~2
Figure 3~6
AI summary
A bladed rotor wheel comprising a blade foot receiving groove provided with locks located on either side of a blade foot insertion notch. According to the invention, the wheel comprises a blade foot receiving groove (14), provided with a blade foot insertion notch and two locks (32) located on either side of the notch; the groove has an upstream annular cavity (20) having a hollowed portion (24) and each lock is provided with an upstream rib (60).