Centrifugal Compressor Scroll Layout for Bundle Clearance
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Solution Overview
Problem
The assemblability of centrifugal compressors is affected when the size of the discharge scroll is changed due to interference with the bundle, including the diaphragm, as described in EP 3239534 A1.
Innovation Solution
A centrifugal compressor design featuring a flow path forming member with a smaller outside diameter than the bundle, fixed to the diaphragm in the axial direction, allowing the size of the discharge scroll to be adjusted without altering the outer casing or diaphragms, and supported by an outer forming member to maintain stability and prevent deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the size of the discharge scroll is reduced, then the flow path efficiency is improved, but the volute piece protrusion amount increases causing interference with the bundle
Solution Approach 1:
The discharge scroll is divided into two separate components: the volute piece and the flow path forming member. The flow path forming member is detached from the volute piece and positioned independently within the discharge scroll, allowing the volute piece to be kept compact while the flow path forming member provides the necessary flow guidance without increasing protrusion.
Solution Approach 2:
The flow path forming member is positioned in the circumferential direction within the discharge scroll, utilizing the circumferential space rather than increasing radial protrusion. This dimensional arrangement allows the flow path to be formed without increasing the protrusion amount of the volute piece from the inner circumferential surface of the casing main body.
2Productivity
If the volute piece is enlarged to reduce discharge scroll size, then the flow path is optimized, but interference with the bundle occurs
Solution Approach 1:
The flow path forming function is extracted from the volute piece and implemented by a separate flow path forming member. This allows the volute piece to maintain a compact size without protruding into the bundle insertion space, while the flow path forming member provides the necessary flow optimization function in the circumferential direction.
Solution Approach 2:
The flow path forming member acts as an intermediary component between the volute piece and the bundle. It provides the necessary flow path formation function while being positioned in the circumferential direction, preventing direct interference with the bundle insertion path and maintaining clear separation between the volute piece and bundle.
3Adaptability or versatility
If the discharge scroll size is changed, then the compression performance is adjusted, but the assemblability is affected
Solution Approach 1:
The flow path forming member is designed to be detachably fixed to the volute piece, allowing for easy assembly and disassembly. This dynamic configuration enables the discharge scroll size and shape to be adjusted for different compression performance requirements while maintaining ease of assembly through simple attachment and detachment operations.
Solution Approach 2:
The flow path forming member serves multiple functions: it forms the flow path, adjusts the discharge scroll effective size, and maintains assemblability. By concentrating these functions in a single detachable component, the system achieves adaptability for different compression performances while preserving ease of assembly and disassembly.
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
Ensures smooth fluid flow and maintains assemblability by preventing interference with the outer casing, allowing the discharge scroll size to be changed without affecting assembly, while ensuring stable performance and ease of assembly and disassembly.
Implementation Method 1
an impeller disposed inside the casing and configured to compress a working fluid supplied from the first side in the axial direction and discharge the compressed working fluid to an outer side in a radial direction with respect to the central axis
Implementation Method 2
a diffuser flow path configured to guide the working fluid discharged from the impeller toward the outer side in the radial direction
Implementation Method 3
a discharge scroll configured to guide the working fluid discharged from the impeller to the discharge port
Data Source
AI summary
A centrifugal compressor includes a rotor shaft including an impeller and a casing including a suction port and a discharge port. The casing includes a diaphragm that covers the rotor shaft, an outer casing that covers the diaphragm, a discharge scroll that guides a working fluid discharged from the impeller to the discharge port, and a flow path forming member including a scroll outer circumferential surface that is located on an outer side in a radial direction and faces an inner side in the radial direction in the discharge scroll. The rotor shaft and the diaphragm form a bundle that is accommodated in the outer casing in an insertable and removable state. The flow path forming member is formed to have an outside diameter smaller than an outside diameter of the bundle in the radial direction, extends in a circumferential direction, and is fixed to the diaphragm from an axial direction.