Compressor Impeller Blade Angle Variation for Rotating Stall Suppression

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Solution Overview

Problem

Compressor impellers face complexity and inefficiency in suppressing rotating stall due to the need for additional suppressing members, which increases the number of parts and complicates the configuration.

Innovation Solution

A compressor impeller design featuring a hub with blades of varying angles, where the leading edges of first and second blades are aligned on the same circle, allowing for differentiated stall characteristics, thereby impairing uniform propagation and development of rotating stall without additional suppressing members.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a suppressing member is added to suppress rotating stall, then rotating stall suppression is improved, but device complexity increases

Engineering Contradiction:
Improverotating stall suppressionVSAvoidconfiguration complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the rotating stall suppression function into the impeller blades themselves by creating two types of blades (first blades and second blades) with different configurations. The second blades have a different blade angle at the leading edge compared to the first blades, and this difference is maintained in at least a partial radial range. This integration eliminates the need for separate suppressing members while achieving the desired stall suppression effect.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent applies local quality by having different blade characteristics at different locations. Specifically, the second blades have a different blade angle configuration compared to the first blades, creating localized variations in blade geometry. This allows different regions of the impeller to have optimized characteristics for their specific flow conditions, with the second blades providing enhanced stall suppression in critical areas.

Inventive Principle:
Principle #3Local quality

2Reliability

If additional suppressing members are added, then rotating stall suppression is improved, but manufacturing complexity increases

Engineering Contradiction:
Improverotating stall suppressionVSAvoidmanufacturing simplicity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent combines the stall suppression functionality with the impeller blade structure itself. By incorporating two types of blades with different geometries directly into the impeller, the design eliminates the need for separate suppressing members that would require additional manufacturing processes, assembly steps, and quality control procedures.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The impeller blades serve multiple functions: they perform the primary compression function while simultaneously providing rotating stall suppression through the differentiated blade configuration. The second blades with different angles serve both as compression elements and as active stall suppression features, reducing the need for specialized components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If blade angles are optimized for low flow rates, then low flow rate performance is improved, but high flow rate intake air amount may decrease

Engineering Contradiction:
Improvelow flow rate stabilityVSAvoidintake air amount
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies local quality by having different blade angle characteristics in different radial ranges. The second blades have different blade angles compared to the first blades, creating localized optimization zones. This allows the impeller to have regions optimized for low flow rate stability while maintaining overall performance across the operational range.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent changes the blade angle parameter to achieve different performance characteristics. By varying the blade angle at the leading edge between the first and second blades, and maintaining this difference in at least a partial radial range, the impeller can optimize performance for different flow rate conditions without sacrificing overall productivity.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3369938B1Compressor impeller and method for manufacturing same
Publication Date: 2019.12.04 MITSUBISHI HEAVY IND ENGINE & TURBOCHARGER LTD
  • EP3369938B1 patent drawingFigure 1
  • EP3369938B1 patent drawingFigure 2
  • EP3369938B1 patent drawingFigure 3

AI summary

A compressor impeller includes: a hub; and a blade group including a plurality of blades arranged along a circumferential direction on an outer peripheral surface of the hub, the blade group being configured such that hub-side ends of leading edges of the respective blades are aligned on the same circle. The plurality of blades include at least one first blade and at least one second blade having a different shape from the at least one first blade. When comparing a blade angle of a leading edge of the at least one first blade to a blade angle of a leading edge of the at least one second blade at the same position in a radial direction of the compressor impeller, the blade angle of the leading edge of the at least one first blade is different from the blade angle of the leading edge of the at least one second blade, at least in a partial range in the radial direction of the compressor impeller.