Centrifugal Compressor Impeller Blade Angle Distribution
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Solution Overview
Problem
Centrifugal compressors face limitations in operating range due to surge and choke issues, which are challenging to address through blade angle distribution adjustments, leading to increased manufacturing costs and decreased efficiency.
Innovation Solution
The implementation of a centrifugal compressor impeller with a specific blade angle distribution that varies from the inlet to the outlet, featuring local maximum and minimum points, allowing for a wider operating range by optimizing flow channel area and preventing surge and choke.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the main dimensions (axial length and diameter of inlet) are adjusted to enlarge the operating range, then the operating range is increased, but the rotor vibration increases and additional design examination is required
Solution Approach 1:
The invention applies local quality by optimizing the blade angle distribution specifically in the flow channel region rather than changing overall impeller dimensions. The blade angle is varied locally from inlet to outlet according to a specific distribution pattern (e.g., convex or concave shape) to control flow characteristics and expand operating range without affecting rotor vibration or requiring additional design examinations.
Solution Approach 2:
The invention changes the geometric parameter of blade angle distribution to achieve the desired effect. By modifying the blade angle distribution parameter (making it convex or concave) rather than changing main dimensions, the operating range is enlarged while avoiding the side effects of dimension changes on rotor vibration and design complexity.
2Adaptability or versatility
If casing treatment is applied to increase the operating range of the small flow rate side, then the operating range is enlarged, but the manufacturing cost increases and efficiency decreases
Solution Approach 1:
The invention achieves the effect of casing treatment through local blade geometry optimization instead of applying physical casing treatment structures. By designing the blade angle distribution to be convex or concave in specific regions, the flow separation at small flow rates is controlled, enlarging the operating range without adding manufacturing complexity or cost.
Solution Approach 2:
The invention extracts the essential function of casing treatment (controlling flow separation to expand operating range) and achieves it through blade geometry design alone, eliminating the need for additional casing treatment components and their associated manufacturing costs.
3Adaptability or versatility
If the blade angle distribution is adjusted to compensate for insufficient operating range, then the operating range is enlarged, but the relationship between blade angle distribution and operating range is not known making it difficult to determine optimal design
Solution Approach 1:
The invention establishes specific parameter ranges for blade angle distribution (convex or concave patterns with defined characteristics) that are proven to enlarge the operating range. This provides clear design guidelines for determining optimal blade angle distribution without requiring complex analysis or trial-and-error approaches.
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 operating range by about 20% at the small flow rate side and 10% at the large flow rate side, reducing surge and choke occurrences, thereby improving efficiency and reducing manufacturing costs.
Implementation Method 1
A centrifugal compressor that compresses fluid using a rotating impeller
Implementation Method 2
flow separation when flow rate decreases more at a small flow rate side
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
It is an object of the prevent invention to provide a centrifugal compressor equipped with an impeller having a blade angle distribution that makes it possible to achieve a relatively wide operating range. In a centrifugal compressor, assuming that a blade angle of a shroud side facing a circular plate of a blade is a first angle and a blade angle of a hub side disposed at the circular plate is a second angle, the shroud side is formed in a curved shape having an angle distribution from a front area in a shaft direction toward a centrifugal direction in which the first angle is the local maximum point before a substantially middle portion and the local minimum point after the substantially middle point, and the hub side is formed in a curved shape having an angle distribution from the front area in the shaft direction toward the centrifugal direction in which the second angle is the maximum local point before the substantially middle portion.