Centrifugal Compressor Diffuser with Flow Dividing Annulus

Solution Overview

Problem

Centrifugal compressors with small chord-pitch ratio diffuser blades face limitations in efficiency, with a narrow operable flow-rate range and low pressure recovery ratio compared to vaned diffusers, and existing solutions do not provide further improvements.

Innovation Solution

Incorporating a flow passage dividing annulus in the diffuser flow passage, which divides the passage into hub-side and shroud-side sections, effectively suppressing boundary layer development by redirecting the boundary layer along the suction surface of the diffuser blades to the annulus walls, thereby enhancing pressure recovery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If small chord-pitch ratio diffuser blades are used, then the operable flow-rate range is widened, but the pressure recovery ratio and efficiency are reduced

Engineering Contradiction:

Improveoperable flow-rate rangeVSAvoidpressure recovery ratio

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The diffuser flow passage is divided into multiple sections by partition walls, creating separate flow paths. This segmentation allows the diffuser to handle varying flow rates more effectively while maintaining pressure recovery, as each section can optimize its flow characteristics independently.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different sections of the diffuser are designed with locally optimized characteristics. The partition walls create zones with different flow angles and expansion ratios, allowing each local region to contribute optimally to overall pressure recovery across a wider flow-rate range.

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If small chord-pitch ratio diffuser blades are used, then the operable flow-rate range is widened, but the efficiency is reduced

Engineering Contradiction:

Improveoperable flow-rate rangeVSAvoidefficiency

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The diffuser flow passage is divided into multiple sections by partition walls, creating separate flow paths. This segmentation allows the diffuser to handle varying flow rates more effectively while maintaining pressure recovery, as each section can optimize its flow characteristics independently.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different sections of the diffuser are designed with locally optimized characteristics. The partition walls create zones with different flow angles and expansion ratios, allowing each local region to contribute optimally to overall pressure recovery across a wider flow-rate range.

Inventive Principle:

Principle #3Local quality

3Loss of energy

If normal vaned diffuser blades are used, then the pressure recovery ratio is improved, but the operable flow-rate range is narrowed

Engineering Contradiction:

Improvepressure recovery ratioVSAvoidoperable flow-rate range

Core Design Contradiction:

Loss of energyVSAdaptability or versatility

Solution Approach 1:

The diffuser flow passage is divided into multiple sections by partition walls, creating separate flow paths. This segmentation allows the diffuser to handle varying flow rates more effectively while maintaining pressure recovery, as each section can optimize its flow characteristics independently.

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 increases the pressure recovery ratio and efficiency of the centrifugal compressor, providing a wider operable flow-rate range and improved performance compared to traditional designs.

Implementation Method 1

effectively suppressing boundary layer development by redirecting the boundary layer along the suction surface of the diffuser blades to the annulus walls

Methodology Applied

Scientific EffectBoundary layer: Boundary Layer

Data Source

PatentUS11085461B2Centrifugal compressor and turbocharger

Publication Date: 2021.08.10 MITSUBISHI HEAVY IND ENGINE & TURBOCHARGER LTD

AI summary

A centrifugal compressor includes an impeller, a diffuser flow passage forming portion forming an annular diffuser flow passage on a downstream side of the impeller, a plurality of small chord-pitch ratio diffuser blades disposed in the diffuser flow passage at intervals in a circumferential direction of the impeller, and a flow passage dividing annulus extending to the diffuser flow passage along a radial direction of the impeller, and dividing the diffuser flow passage into a hub-side flow passage and a shroud-side flow passage.