Centrifugal Compressor Impeller Blade Angle Gradient
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Solution Overview
Problem
In centrifugal compressors, the large change in blade angle leads to increased shock wave and peeling generation at the impeller inlet, resulting in inefficient fluid compression due to higher pressure loss.
Innovation Solution
The impeller design features a constant first blade angle at the inlet, a gradual increase in blade angle towards the outlet, and a gentler shape change from the hub to the tip, reducing shock waves and pressure loss by maintaining a stable fluid flow and preventing secondary flow disturbances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the blade angle changes significantly to optimize blade shape, then the blade can achieve better compression performance, but shock waves and peeling are generated at the impeller inlet, increasing pressure loss and reducing compression efficiency
Solution Approach 1:
The patent applies parameter changes by optimizing the blade angle distribution along the blade length. Specifically, the blade angle is designed to be relatively small at the inlet portion and gradually increase toward the outlet portion, creating a continuous gradient that avoids abrupt angle changes. This parameter optimization resolves the contradiction by enabling effective compression while preventing shock wave generation and peeling that would otherwise cause excessive pressure loss.
Solution Approach 2:
The patent employs curvature principles by designing the blade with a smooth, continuous curved profile rather than sharp angular transitions. The blade angle distribution follows a gradual curve from inlet to outlet, eliminating discontinuities in the blade geometry. This curved design ensures smooth fluid flow along the blade surface, preventing flow separation and shock waves while maintaining compression effectiveness.
2Productivity
If the blade angle is increased at the outlet to improve compression, then compression performance may improve, but secondary flow strengthens and disturbs fluid flow, reducing compression efficiency
Solution Approach 1:
The patent applies parameter changes by carefully controlling the blade angle distribution to balance compression performance with flow stability. The blade angle is designed to increase gradually from inlet to outlet, but the rate of increase is optimized to prevent excessive secondary flow. This parameter optimization ensures that the outlet blade angle provides sufficient compression while maintaining stable fluid flow without strong secondary flow disturbances.
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 compression efficiency by ensuring smooth fluid flow, reducing pressure loss, and maintaining a consistent pressure balance across the impeller, thereby improving the overall performance of the compressor.
Implementation Method 1
The rotary machine rotates the impeller, thereby increasing the pressure of a fluid drawn in from the outside of the casing and discharging the fluid to the outside in a radial direction of a flow path in the impeller
Implementation Method 2
the generation of a shock wave or peeling in the vicinity of an impeller inlet where a fluid flows in is promoted
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The impeller (1) is provided with a disk (11) that rotates about an axis line (O), and a plurality of blades (12) provided at intervals around the circumference of the disk (11). Defining the blade angle (β) of the tip of each blade (12) as a first blade angle, the tip has a constant-tip-angle area in which the first blade angle is constant from an inlet where fluid flows in toward an outlet side, and an increasing-tip-angle area that is continuous with the outlet side of the constant-tip-angle area and that has a gradually increasing first blade angle towards the outlet.