Diffuser Vane Clearance in Centrifugal Compressors for Lower Exciting Force

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Solution Overview

Problem

Centrifugal compressors experience rotor-stator interaction, leading to increased exciting force, which is undesirable.

Innovation Solution

A centrifugal compressor design featuring a diffuser flow path with vanes and surfaces that include a clearance extending radially outward, narrowing at a specific position, and optionally allowing vane rotation, to reduce exciting force while minimizing efficiency loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If vanes are installed in the diffuser flow path, then gas flow control is improved, but rotor-stator interaction increases causing excessive exciting force

Engineering Contradiction:

Improvegas flow controlVSAvoidexciting force

Core Design Contradiction:

ProductivityVSForce

Solution Approach 1:

The patent applies local quality by creating a clearance specifically at the leading edge portion of the vanes rather than uniformly across the entire vane structure. This localized clearance modifies the flow interaction only in the critical region where rotor-stator interaction occurs, allowing gas flow control to be maintained while reducing the exciting force generated by rotor-stator interaction.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent introduces a radial dimension by creating a clearance that extends in the radial direction from the leading edge of the vanes. This dimensional approach allows the clearance to interact with the radial flow components, effectively modifying the rotor-stator interaction mechanism without compromising the tangential flow control function of the vanes.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Force

If clearance is formed between vanes and diffuser surfaces, then exciting force is reduced, but flow path efficiency may deteriorate

Engineering Contradiction:

Improveexciting forceVSAvoidflow path efficiency

Core Design Contradiction:

ForceVSLoss of energy

Solution Approach 1:

The patent applies partial action by forming the clearance only at the leading edge portion of the vanes rather than across the entire vane span. This partial clearance configuration is sufficient to reduce rotor-stator interaction and exciting force, while minimizing the impact on overall flow path efficiency by maintaining full contact at other critical regions.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The patent segments the vane structure into different functional zones: the leading edge portion with clearance for reducing exciting force, and other portions maintaining full contact for efficient flow control. This segmentation allows each zone to perform its specific function optimally without compromising the other.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS20260016023A1Centrifugal compressor

Publication Date: 2026.01.15 IHI CORP

AI summary

The centrifugal compressor includes a compressor impeller, a diffuser flow path that is located outside the compressor impeller in a radial direction and into which fluid from the compressor impeller flows, a plurality of vanes that is provided in the diffuser flow path and that is arranged along a circumferential direction, a first surface that defines the diffuser flow path, and a second surface that defines the diffuser flow path and that faces the first surface across the plurality of vanes, wherein a clearance is formed between each of the plurality of vanes and at least one of the first surface and the second surface, the clearance extending radially outward from a leading edge of each of the plurality of vanes and being closed or narrowed at a position between the leading edge and a trailing edge.