Co-injected Composite Shell for Axial Compressor Assembly
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Solution Overview
Problem
The assembly of axial turbomachine stator shells is time-consuming due to the manual application of elastomers and the need for surface preparation, such as sanding and primer application, to ensure a satisfactory bond between the abradable material and the shell.
Innovation Solution
A segmented stator shell made of polymeric material with co-injected working surfaces, where the first material is thermoplastic or thermosetting and the second material is elastomeric or TEFLON, allowing for direct mating with blades and eliminating the need for manual elastomer application and surface preparation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual application of elastomer is used to connect blades and segments, then bonding between blades and shell is achieved, but assembly time is excessive
Solution Approach 1:
The elastomeric material is pre-applied to the segment ends and blade interfaces during the injection molding process, forming a pre-prepared bonding surface that eliminates the need for manual elastomer application during assembly. This preliminary action integrates the bonding material preparation into the manufacturing process itself.
Solution Approach 2:
The invention merges the shell structure with the bonding elastomeric material into a single integrated component. The elastomeric material is co-injected with the shell material, combining what were previously separate elements (shell and bonding material) into one unified part that requires no separate bonding step during assembly.
2Reliability
If sanding and primer application are performed on the shell surface, then bonding of abradable material is improved, but assembly time increases
Solution Approach 1:
The elastomeric surface layer is pre-formed on the shell during injection molding, creating a ready-to-receive abradable material surface without requiring subsequent sanding or primer application. This preliminary formation of the bonding surface eliminates time-consuming surface preparation steps.
Solution Approach 2:
The invention changes the surface material parameter from a rigid polymer requiring mechanical preparation to an elastomeric material that provides inherent bonding properties. This parameter change in material selection and surface properties eliminates the need for surface modification processes.
3Ease of manufacture
If a single-material polymer shell is used, then manufacturing is simple, but bonding performance with blades and abradable material is insufficient
Solution Approach 1:
The shell is constructed as a composite structure with two distinct material zones: a rigid polymer forming the main shell body for structural integrity, and an elastomeric material forming the bonding surfaces for optimal adhesion. This composite approach combines the advantages of both material types within a single integrated component.
Solution Approach 2:
Different regions of the shell are assigned different material properties: the main body uses rigid polymer for structural strength, while the contact surfaces use elastomeric material for bonding performance. This local differentiation of material quality optimizes each region's function while maintaining manufacturing efficiency through co-injection.
4Ease of operation
If segmented shell design is implemented, then assembly and maintenance become easier, but the number of components and assembly steps increases
Solution Approach 1:
The bonding elastomeric material is pre-applied to all segment ends and blade interfaces during manufacturing, so that segmented components can be directly assembled without requiring additional bonding operations. This preliminary preparation of bonding surfaces simplifies the assembly process despite the increased number of components.
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 co-injection process simplifies the assembly by forming cohesive working surfaces during moulding, reducing assembly time and enhancing the bonding between the shell and abradable material, thereby improving the efficiency and economy of the turbomachine stator shell assembly.
Implementation Method 1
the second material is injected after the first material. The segment is injection moulded in a constant volume mould or in a variable volume mould
Data Source
AI summary
A segmented composite shell for an axial turbomachine compressor, each segment formed of a first polymeric material and comprises at least one working surface formed of a second polymeric material co-injected with the first polymeric material. The working surface can be a contact surface with a blade, wherein the working surface has a lipped profile and is made of an elastomeric material. The working surface can be the inner surface for bonding an abradable material, wherein the material can be silicone to facilitate the bonding of the abradable material to the silicone base. The working surface can be a lateral face of the shell that contacts a mating fixed surface, wherein the material can comprise TEFLON®, i.e. Polytetrafluoroethylene (PTFE), so as to form a working surface with dry friction properties. Such features enable the shell to have additional technical features implemented directly during the injection moulding of the shell segments.