Turbine Wear Liners With Interlocking Protrusions
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Solution Overview
Problem
In turbomachines, such as aircraft turbojets and turboprops, the anti-wear foils can overlap during assembly or operation due to vibrations and thermal variations, leading to potential damage and inefficiencies in thermal management.
Innovation Solution
The foils are designed with protuberances or recesses that prevent overlap by allowing them to support each other directly, with protuberances extending from the circumferential ends and recesses on the ring that block rotation, ensuring correct positioning and preventing mutual overlap during assembly and operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If anti-wear shims are installed between the ring hook and distributor without protrusions or recesses, then the assembly is simple and quick, but the shims can overlap during assembly or operation due to vibrations and thermal variations
Solution Approach 1:
The shim is segmented with protrusions extending from its edges, dividing the continuous shim into sections that interlock with adjacent shims. This segmentation prevents the shims from overlapping during assembly or operation while maintaining the overall simplicity of the assembly process.
Solution Approach 2:
The shim features asymmetric protrusions and recesses positioned at specific locations (edges or faces) rather than uniform features throughout. This asymmetric design creates a directional interlocking mechanism that prevents overlap in the critical directions while minimizing added complexity.
2Temperature
If the distributor fins are exposed to hot airflow, then thermal protection of the casing hooks is compromised, but insulating the hooks requires additional complex thermal barriers
Solution Approach 1:
The anti-wear shims perform multiple functions simultaneously: they provide thermal insulation between the hot distributor fins and the casing hooks, prevent overlap through their protrusion-recess geometry, and protect against wear. This multi-functionality eliminates the need for separate thermal barriers, maintaining simplicity while achieving temperature control.
Solution Approach 2:
The shims act as an intermediary thermal barrier positioned between the hot distributor fins and the casing hooks. This intermediate layer insulates the hooks from heat while allowing the distributor fins to remain exposed to the hot airflow for their aerodynamic function.
3Productivity
If shims are blindly mounted during assembly, then the assembly process is fast, but mutual overlap of shims cannot be detected or prevented
Solution Approach 1:
The protrusions and recesses are pre-formed features on the shims before assembly. This preliminary action ensures that when shims are installed, their positions are automatically constrained by the interlocking geometry, preventing overlap without requiring precise manual positioning or inspection during assembly.
Solution Approach 2:
The shim design is self-positioning through its protrusion-recess geometry. During assembly, each shim automatically finds its correct position and prevents overlap with adjacent shims through the mechanical interlocking of features, eliminating the need for external guidance or inspection mechanisms.
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 design effectively prevents foil overlap, enhances thermal insulation by maintaining the coolness of the crankcase hooks, and reduces gas leaks, thereby improving the overall efficiency and reliability of the turbomachine.
Implementation Method 1
the goal is to keep the casing hooks (or rails) relatively cool and therefore insulate them as much as possible from the distributor fins, which are relatively hot and whose temperatures are close to the aerodynamic flow temperature. The shims help limit heat conduction between the casing hooks and the distributor fins.
Data Source
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AI summary
The turbine (12) for a turbine engine (100) extends around a major axis (X-X) and comprises: - a casing (4) comprising an annular hook (38), - a movably mounted impeller (16), - a ring (30) extending opposite the impeller in a direction radial to the major axis (XX), - a distributor (14) comprising a blade provided with a platform (11), the platform being extended radially outwards by a spoiler (22, 24), the spoiler (22, 24) being radially mounted on the hook (38), and - foils (40) each having a profiled trough shape in a direction circumferential to the axis, the foils extending in succession in the circumferential direction, each foil (40) extending between the spoiler (22, 24) and the hook (38). The turbine comprises stops (162) to prevent the foils (40) from moving in the circumferential direction. Each foil (40) comprises a protrusion (162) arranged so as to extend circumferentially opposite another protrusion (162) of another adjacent foil (40).