Diffuser Blade Geometry for Low-Flow Centrifugal Compressors

Solution Overview

Problem

Centrifugal compressors face challenges in reducing the throat area when operating at low fluid flow rates, which affects the efficiency of fluid pressurization.

Innovation Solution

The design of diffuser blades with local maximum blade angles and thicknesses on specific positions relative to adjacent blades, allowing for a reduction in the throat area without increasing pressure loss or complicating manufacturing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the throat area is reduced to improve efficiency at low flow rates, then the compressor performance at low flow rates improves, but the manufacturing complexity and pressure loss increase

Engineering Contradiction:

Improvecompressor efficiency at low flow rateVSAvoiddiffuser blade geometry complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The diffuser blade employs non-uniform thickness distribution with a local maximum thickness position that is offset from the blade centerline. This local quality variation allows the throat area to be reduced in specific regions while maintaining structural integrity and controlling pressure loss, thereby improving low flow rate efficiency without proportionally increasing manufacturing complexity

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The blade angle and thickness parameters are optimized with specific relationships: the thickness has a local maximum at a position offset from the blade centerline, and the blade angle has a local maximum at a different position. This parameter optimization reduces the throat area while controlling pressure loss, achieving improved compressor performance at low flow rates

Inventive Principle:

Principle #35Parameter changes

2Productivity

If the throat area is reduced to improve efficiency at low flow rates, then the compressor performance at low flow rates improves, but the pressure loss increases

Engineering Contradiction:

Improvecompressor efficiency at low flow rateVSAvoidpressure loss

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The diffuser blade employs non-uniform thickness distribution with a local maximum thickness position that is offset from the blade centerline. This local quality variation allows the throat area to be reduced in specific regions while maintaining structural integrity and controlling pressure loss, thereby improving low flow rate efficiency without proportionally increasing manufacturing complexity

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The blade angle and thickness parameters are optimized with specific relationships: the thickness has a local maximum at a position offset from the blade centerline, and the blade angle has a local maximum at a different position. This parameter optimization reduces the throat area while controlling pressure loss, achieving improved compressor performance at low flow rates

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20250341221A1Centrifugal compressor

Publication Date: 2025.11.06 IHI CORP

AI summary

Provided is a centrifugal compressor, including: a compressor impeller; and a plurality of diffuser blades arranged on an outer side of the compressor impeller in a radial direction so as to be spaced apart from each other in a circumferential direction of the compressor impeller, the diffuser blades each with: a blade angle having a local maximum value, the blade angle being an angle formed between a center line of the diffuser blade and the radial direction; and a thickness having a local maximum on a downstream side of a position at which the blade angle has the local maximum value.