Intermediate Intake Diaphragm for Centrifugal Compressor Flow Matching
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Solution Overview
Problem
In multistage centrifugal compressors, the pressure loss of fluid increases due to the joining of working gas and intermediate suction flow with different flow directions, leading to increased shearing forces and turbulence, which reduces operational efficiency.
Innovation Solution
An intermediate intake-type diaphragm is designed with specific flow channels and vanes that regulate the flow direction of both fluids before joining, reducing velocity differences and turbulence by using an introduction flow channel, intermediate suction flow channel, and curved flow channel, along with a partition wall and guide vanes to align the flow directions before changing from radial to axial flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the working gas and intermediate suction flow are joined directly in the return flow channel portion, then the device complexity is reduced, but the pressure loss of the fluid increases due to flow direction mismatch and shearing forces
Solution Approach 1:
The return flow channel portion is divided into a first region and a second region by a partition wall. The first region receives working gas from the U-shaped cross-section portion, while the second region receives intermediate suction flow from the intermediate stage injection nozzle. This segmentation allows independent flow path optimization for each fluid stream, enabling direction matching before joining without significantly increasing overall structural complexity.
Solution Approach 2:
The partition wall is positioned to enable preliminary flow direction adjustment before the working gas and intermediate suction flow are joined. By configuring the partition wall's radially inner end portion at a specific location between the radially outer end portion of the flow-regulating vane and the boundary with the curved flow channel, the flows are pre-aligned in the axial direction before mixing, reducing shearing forces and pressure loss.
2Loss of energy
If a partition wall is used to match flow directions before joining, then the pressure loss is reduced, but the device complexity increases
Solution Approach 1:
The partition wall is strategically positioned only in the critical region where flow direction matching is needed, rather than dividing the entire return flow channel. The radially inner end portion of the partition wall is located at a specific position that provides sufficient flow separation and direction alignment while minimizing the partition's extent, thus reducing the added structural complexity.
Solution Approach 2:
The partition wall extends partially through the return flow channel portion in the axial direction, providing just enough flow separation to achieve direction matching. This partial action is sufficient to reduce pressure loss without creating excessive structural complexity that would result from a complete division of the flow channel.
3Speed
If the flow channel changes from radial to axial direction, then the fluid is properly directed toward the impeller, but the velocity difference between flows increases and shearing force is generated
Solution Approach 1:
The partition wall is configured with specific positioning in the radial direction, where its radially inner end portion is located at a precise position between the flow-regulating vane's radially outer end portion and the curved flow channel boundary. This dimensional positioning creates a three-dimensional flow separation that allows both radial and axial flow components to coexist and merge smoothly, reducing velocity differences during the directional transition.
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 effectively reduces pressure loss and improves operational efficiency by minimizing the velocity difference and turbulence between the fluids, enhancing the overall performance of the centrifugal rotating machine.
Implementation Method 1
a flow-regulating vane that is provided in the introduction flow channel to regulate the first fluid to flow along the radial direction; a guide vane configured to regulate the second fluid to flow along the radial direction
Implementation Method 2
the curved flow channel being connected to downstream sides of the introduction flow channel and the intermediate suction flow channel and extending so that an inner surface is curved from a position of connection with the introduction flow channel toward one side in the direction of the axial line
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An introduction flow channel (51) configured to guide a first fluid (G1) toward an impeller (3), an intermediate suction flow channel (62) adjacent to the introduction flow channel (51) and configured to guide a second fluid (G2) toward the impeller (3), and a curved flow channel (52) connected to downstream sides of the introduction flow channel (51) and the intermediate suction flow channel (62) are defined. The curved flow channel (52) extends so that an inner surface is curved from a position of connection with the introduction flow channel (51) toward one side in the direction of the axial line (O). The diaphragm includes a flow-regulating vane (54) that is provided in the introduction flow channel (51) to regulate the first fluid (G1) to flow along the radial direction; and a partition wall (9) that partitions the introduction flow channel (51) and the intermediate suction flow channel (62) in the direction of the axial line (O). A radially inner end portion (9c) of the partition wall (9) is located further on a radially inner side than a radially outer end portion (54d) of the flow-regulating vane (54), and further on a radially outer side than a boundary (F) between the introduction flow channel (51) and the curved flow channel (52).