Splitter Blade Angle Variation for Centrifugal Compressor Flow
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Solution Overview
Problem
Conventional centrifugal compressor impellers face challenges in achieving evenly distributed flow rates and pressure due to complex fluid flows, leading to inefficiencies and increased dissipation losses, as the existing blade geometries are not compatible with the intricate flow patterns within the compressor.
Innovation Solution
The impeller design features a splitter blade geometry where the leading edge blade angle is gradually inclined towards the blade pressure surface near the hub surface, with a specific angle distribution based on height level, to accommodate secondary flows and tip clearance leakage, ensuring smooth fluid flow and reduced separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the leading edge blade angle of the splitter blade is increased to equalize throat areas, then the throat area distribution is improved, but fluid flow separation occurs at the leading edge
Solution Approach 1:
The patent applies local quality by differentiating the blade angle configuration between different regions of the splitter blade. Specifically, the blade angle at the leading edge portion is set to be smaller than the blade angle at the trailing edge portion, creating a non-uniform angular distribution that optimizes both flow attachment and throat area characteristics in different zones of the blade
2Ease of manufacture
If the splitter blade geometry is simply formed by removing a part of the full blade, then the manufacturing complexity is reduced, but the flow rate distribution between pressure surface and suction surface becomes uneven
Solution Approach 1:
The patent implements local quality by specifying different blade angle characteristics for different portions of the splitter blade. The leading edge portion has a smaller blade angle while the trailing edge portion has a larger blade angle, creating region-specific optimizations that ensure even flow rate distribution while maintaining manufacturing feasibility through defined geometric parameters
Solution Approach 2:
The patent applies parameter changes by systematically varying the blade angle parameter along the span of the splitter blade. By defining the blade angle as a function of position (smaller at leading edge, larger at trailing edge), the design transforms a simple cut geometry into an optimized configuration that controls flow distribution without requiring complex manufacturing processes
3Manufacturing precision
If the leading edge blade angle is increased toward the flow inlet direction, then the throat area on the pressure surface side is increased, but the velocity difference between flow passages increases leading to uneven flow rates
Solution Approach 1:
The patent resolves this contradiction by applying local quality through position-dependent blade angle specification. The blade angle is set to be smaller at the leading edge portion and larger at the trailing edge portion, creating localized flow control that balances both throat area characteristics and velocity distribution across the different flow passages
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 design enhances the pressure ratio and efficiency by evenly distributing flow rates and preventing flow separation, thus improving the overall performance of the centrifugal compressor.
Implementation Method 1
there is apprehension that the fluid flow around the leading edge part where the slope of the splitter blade 09 is increased is separated from the blade; and, there is apprehension that the fluid flow along the blade suction surface side Sb of the full blade is separated from the blade
Implementation Method 2
the centrifugal compressor delivers the fluid outside of the compressor toward the radial direction so as to increase the pressure of the fluid by use of the centrifugal force given to the fluid
Data Source
Figure 1~2
Figure 3~5
Figure 6~7
AI summary
An impeller (1) for a centrifugal compressor, the impeller comprising: a plurality of full blades (5) provided on a hub surface from a working fluid inlet part of the impeller to a fluid outlet part of the impeller; and a plurality of splitter blades (7), each splitter blade (7) being provided between the full blade (5) and the adjacent full blade (5) from a middle of a flow passage (9) formed between the full blades (5) to the fluid outlet part of the impeller (1), wherein a leading edge blade angle (Θ) of a flow entering front-end-part of the splitter blade (7) is varied depending on a height level from the hub surface in a height direction, further wherein a hub side part of the flow entering front-end-part of the splitter blade (7) is inclined smoothly toward a blade pressure surface side of the full blade (5), at a greater inclination angle than an inclination angle of other part of the flow entering front-end-part.