Centrifugal Compressor Return Channel Vanes for Flow Straightening
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Solution Overview
Problem
Existing centrifugal compressor designs face challenges in effectively removing tangential velocity components of fluid due to difficulties in joining front and rear vanes, leading to reduced compression efficiency.
Innovation Solution
The design includes a return channel with front and rear vanes arranged in circular arrays on the hub-side and shroud-side wall surfaces, where the front vanes are formed on a separate annular member that is fitted to the channel, allowing for easier joining and improved tangential velocity component removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If front vanes and rear vanes are directly joined to hub-side or shroud-side wall surfaces, then the structure is simple, but the joining process becomes difficult due to inaccessibility of welding rod routes
Solution Approach 1:
The return channel is divided into multiple segments: hub-side wall surface, shroud-side wall surface, front vanes, and rear vanes. Each component can be manufactured separately and then assembled, allowing welding operations to be performed on accessible surfaces rather than attempting to join components in a constrained space where welding rods cannot reach.
Solution Approach 2:
The front vanes and rear vanes act as intermediary components that connect the hub-side and shroud-side wall surfaces. By joining vanes to wall surfaces at accessible locations rather than attempting direct joining across the return channel, the welding rod accessibility problem is resolved while maintaining structural integrity.
2Reliability
If front and rear vanes are designed to avoid joining failure, then joining reliability is improved, but tangential velocity component removal ability deteriorates
Solution Approach 1:
By segmenting the vane structure into front vanes and rear vanes that are separately formed and then joined to wall surfaces, the design achieves both reliable joining (at accessible locations) and effective fluid flow control (through optimized vane geometry and arrangement).
Solution Approach 2:
The joining locations are strategically selected at specific local areas of the wall surfaces where welding rod access is feasible, while the vane geometry and arrangement are optimized locally to maximize tangential velocity component removal. This allows different parts of the structure to serve different functions: reliable joining at accessible locations and effective fluid control at critical flow locations.
3Ease of manufacture
If front and rear vanes are cut out of hub-side or shroud-side wall surfaces, then joining is simplified, but manufacturing flexibility and joining accessibility are reduced
Solution Approach 1:
The vane structure is segmented into separable components (front vanes and rear vanes) that can be manufactured using different methods and then assembled. This provides manufacturing flexibility to choose appropriate processes for each component while maintaining simplified joining at accessible locations.
Solution Approach 2:
The design allows for dynamic selection of manufacturing approaches - vanes can be formed separately and joined, or integrated with wall surfaces, depending on specific application requirements. This adaptability enables optimization for different production volumes, material types, and geometric complexities.
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 enhances the ability to remove tangential velocity components, improving the efficiency of the centrifugal compressor by facilitating easier vane joining and maintaining a small gap between vanes.
Implementation Method 1
The annular member is fitted to the return channel
Implementation Method 2
causes the fluid flowing from the diffuser to the centrifugal impeller of the subsequent stage to flow in a return direction toward the rotation shaft
Implementation Method 3
efficiently redirect the flow and remove tangential velocity components of the fluid to straighten the flow
Implementation Method 4
a centrifugal impeller rotated to give energy to fluid
Implementation Method 5
a diffuser converting kinetic pressure of the fluid having increased pressure, into static pressure
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
In the centrifugal compressor, the return channel is provided between a hub-side wall surface and a shroud-side wall surface. The return channel includes a front set of vanes arranged in a circular array on the upstream side and a rear set of vanes arranged in a circular array on the downstream side. The front set of vanes and the rear set of vanes are both formed on the shroud-side wall surface. The front set of vanes is formed on an annular member that is formed separately from the rear set of vanes. The annular member is fitted to the return channel. According to the above, it is possible to improve the tangential velocity component removal ability of front and rear vanes provided in the return channel of a centrifugal compressor.