Centrifugal Compressor Diffuser-Rectifier Connection
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Solution Overview
Problem
Existing aeronautical turbomachines face issues with imperfect connections and poor sealing quality between the diffuser and rectifier in centrifugal compressors, leading to misalignment, increased mass, and difficulty in assembly and disassembly, particularly due to the use of flanges that can deform under vibrations or thermal expansion.
Innovation Solution
A connecting device featuring a diffuser with a double disc shape and a curved O-ring rectifier, secured by a screw and nut connection positioned near the contact surface, eliminating the need for additional support means and ensuring easy assembly and disassembly with standard tools, while maintaining precise alignment of air circulation ducts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If flanges are used to connect the diffuser and rectifier, then the connection is simple to assemble, but the flanges deform under vibrations or thermal expansion causing misalignment and poor sealing
Solution Approach 1:
The connection system is segmented into a clamp component and a retaining component that can be independently assembled. The clamp applies radial force while the retaining component maintains axial positioning, separating the functions of alignment and securing to prevent deformation-induced misalignment.
Solution Approach 2:
The retaining component acts as an intermediary between the diffuser and rectifier, providing a stable reference surface that prevents direct contact and potential deformation between the main components. This intermediary ensures consistent alignment despite vibrations or thermal expansion.
2Weight of moving object
If a hooping connection is used to rigidly associate the diffuser and rectifier, then mass is reduced and flow continuity is improved, but the assembly requires heating or cooling means and cannot be dismantled with traditional tools
Solution Approach 1:
The connection system transitions from a static rigid hooping to a dynamic adjustable clamp-retainer system. The clamp can be tightened or loosened using standard tools, allowing the connection to adapt during assembly and disassembly without requiring thermal processing or specialized equipment.
Solution Approach 2:
Instead of using thermal expansion/contraction to assemble (as in hooping), the invention uses mechanical expansion/contraction of the clamp through screw adjustment. The assembly process is inverted from heating-based to tool-based, enabling dismantling with traditional tools.
3Ease of operation
If bolted flange connections are used, then assembly is simple, but additional parts increase mass and the flanges can deform under thermal expansion
Solution Approach 1:
The clamp and retaining component are designed to work together as an integrated connection system that combines the alignment function of flanges with the securing function of bolting, eliminating the need for separate heavy flange structures while maintaining assembly simplicity.
4Strength
If the rectifier is bolted to the diffuser at its upstream end, then the connection is secure, but the sealing quality is poor and misalignment occurs
Solution Approach 1:
The connection system applies different qualities to different parts: the clamp provides radial compression for sealing at the contact surface, while the retaining component provides axial positioning for alignment. This localized functional differentiation ensures both sealing and alignment without compromising overall connection strength.
Data Source
Figure 1~4
Figure 5~7
AI summary
The invention relates to an assembly consisting of a diffuser (1) and an airflow rectifier (2) at the outlet of a centrifugal compressor of a turbine engine, said diffuser being substantially in the shape of a radially positioned double annular disc, and said rectifier being a double toroidal part, arranged as an extension of the double disc of the diffuser and curved such as to divert the airflow in the downstream direction of the engine, characterised in that said rectifier is attached to said diffuser by a connection positioned immediately adjacent to the contact surface of the two parts and is removable using a standard tool, excluding any other supporting means.