Axial Compressor Forward Stator Blade Row Design

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Solution Overview

Problem

In axial flow type compressors, high inflow mach numbers lead to increased pressure loss and choking in the throat portion, limiting airflow rate, and existing solutions fail to effectively reduce pressure loss while maintaining noise advantages.

Innovation Solution

The compressor blade row is designed with a basic and forward blade row configuration, where the forward blade row has a smaller number of blades and larger circumferential intervals, reducing fluid friction loss and expanding the throat area, thereby enhancing airflow rate and reducing pressure loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If the number of stator blades is increased to reduce noise, then noise is reduced, but the area between blades decreases leading to increased pressure loss and choking

Engineering Contradiction:
ImprovenoiseVSAvoidpressure loss
Core Design Contradiction:
Object-generated harmful factorsVSLoss of energy

Solution Approach 1:

The blade row is segmented into two distinct rows: a basic blade row with a larger number of blades for noise reduction, and a forward blade row with fewer blades for maintaining airflow capacity. This segmentation allows both noise control and performance preservation to coexist

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention adds a circumferential dimension to the blade arrangement by creating overlapping blade rows at different angular positions. The forward blade row is positioned to lead the basic blade row circumferentially, creating a three-dimensional blade configuration that manages both noise and flow characteristics

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Object-generated harmful factors

If the number of rotor blades is increased to reduce noise, then noise is reduced, but fluid friction loss increases

Engineering Contradiction:
ImprovenoiseVSAvoidfluid friction loss
Core Design Contradiction:
Object-generated harmful factorsVSLoss of energy

Solution Approach 1:

The rotor blade row is segmented into a basic rotor blade row and a forward rotor blade row, with the forward row having fewer blades positioned to lead circumferentially. This reduces the total number of blade interactions while maintaining noise control

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The blade rows are designed with different circumferential positions and spacing, creating a dynamic flow path where the forward blade row guides flow before it encounters the basic blade row, optimizing the interaction between blades and reducing friction loss

Inventive Principle:
Principle #15Dynamics

3Stress or pressure

If chord length is increased to handle high pressure at radial inner diameter, then pressure handling capability is improved, but friction loss increases

Engineering Contradiction:
Improvepressure handling capabilityVSAvoidfriction loss
Core Design Contradiction:
Stress or pressureVSLoss of energy

Solution Approach 1:

The forward blade row is designed with specific chord lengths and spacing optimized for local flow conditions at different radial positions. This allows appropriate pressure handling capability without excessive chord length that would increase friction loss

Inventive Principle:
Principle #3Local quality

4Productivity

If the passageway sectional area is expanded at the throat portion, then choking is reduced, but the blade row structure becomes more complex

Engineering Contradiction:
Improveairflow rateVSAvoidblade row structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

Instead of modifying a single blade row structure, the invention segments the blade row into two rows where the combined effect naturally expands the effective passageway area at the throat portion, reducing choking without requiring complex modifications to individual blades

Inventive Principle:
Principle #1Segmentation

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 increases airflow rate while maintaining compression characteristics, as verified by CFD analysis, and also decreases weight and noise interference.

Implementation Method 1

the forward blade row has a smaller number of blades and larger circumferential intervals, reducing fluid friction loss

Methodology Applied
Scientific EffectFluid friction: Friction

Implementation Method 2

a compressor for compressing an air introduced from the outside is configured as an axial flow type compressor

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 3

since an inflow mach number becomes high at a position on the side of a radial inner diameter, choking easily occurs in a minimum valid passageway sectional portion

Methodology Applied
Scientific EffectChoking: Speed of Sound

Data Source

PatentEP2096320B1Cascade of axial compressor
Publication Date: 2018.02.28 IHI CORP
  • EP2096320B1 patent drawingFigure 1~2
  • EP2096320B1 patent drawingFigure 3
  • EP2096320B1 patent drawingFigure 4A~4D

AI summary

In a blade row of an axial flow type compressor in which a rotor blade row and a stator blade row are alternately arranged in an axial direction, the stator blade row 10 is formed by plural main stator blades 12 and plural sub-stator blades 14. Each main stator blade 12 is formed by a basic blade portion 12a which has the same shape as that of each sub-stator blade and a forward blade portion 12b which extends to the upstream side of the basic blade portion. The basic blade portion 12a are located at the same position in an axial direction. The forward blade portion 12b forms a forward stator blade row which has a circumferential interval larger than that of the basic stator blade row in the vicinity of at least a radial inner end.