Gas Expander Vortex Preventer for Flow Uniformity

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Solution Overview

Problem

Existing gas expanders do not effectively suppress vortex flow, leading to non-uniform flow velocity distribution and exciting forces on the impeller and rotating shaft, causing vibration.

Innovation Solution

A gas expander configuration that includes a vortex preventer with profile and plate rectifying blades, positioned downstream of the impeller, to rectify the swirling component of the vortex flow and ensure uniform flow velocity distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a vortex prevention plate is used to suppress vortex flow, then the vortex flow is partially suppressed, but the flow velocity distribution becomes non-uniform and exciting forces are generated

Engineering Contradiction:
Improvevortex flow suppressionVSAvoidflow velocity distribution uniformity
Core Design Contradiction:
Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The vortex prevention plate is divided into multiple segments in the circumferential direction, with each segment independently positioned to intercept vortex flow at different angular positions. This segmentation allows the plate to suppress vortex flow while maintaining symmetric flow distribution patterns that prevent exciting forces on the impeller and rotating shaft

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The vortex prevention plate is positioned at specific radial and axial locations within the diffuser, and its width and positioning are optimized to address vortex flow characteristics at different locations. The plate's local placement and dimensions are tailored to suppress vortex flow where it occurs while preserving uniform flow distribution in other regions

Inventive Principle:
Principle #3Local quality

2Object-affected harmful factors

If the vortex prevention plate intercepts the vortex flow, then the vortex flow is suppressed, but a reflected flow component is generated that causes non-uniform flow velocity distribution

Engineering Contradiction:
Improvevortex flow suppressionVSAvoidreflected flow component
Core Design Contradiction:
Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The vortex prevention plate is designed to convert the harmful reflected flow component into a beneficial effect by positioning multiple plates symmetrically. The reflected flows from different segments interact and cancel each other out, transforming what would be a harmful non-uniform flow distribution into a uniform flow pattern that does not generate exciting forces

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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

The configuration effectively suppresses the exciting force on the impeller and rotating shaft, reducing turbulence and ensuring a uniform flow velocity distribution downstream of the impeller, thereby minimizing vibration.

Implementation Method 1

a vortex preventer 6 provided in the flow path 50, the vortex preventer 6 having a flow rectifying function of suppressing a vortex flow Fs

Methodology Applied
Scientific EffectVortex flow suppression: Turbulence

Implementation Method 2

The gas expander converts thermal energy of a working fluid having high temperature and high pressure into rotational energy by rotating an impeller and a rotating shaft with the working fluid

Methodology Applied
Scientific EffectThermal energy conversion: Heat Engine

Data Source

PatentEP4047186B1Gas expander
Publication Date: 2023.11.15 MITSUBISHI HEAVY INDUSTIES COMPRESSOR CORP
  • EP4047186B1 patent drawingFigure 1
  • EP4047186B1 patent drawingFigure 2
  • EP4047186B1 patent drawingFigure 3

AI summary

A gas expander includes a scroll casing, an impeller accommodated in the scroll casing and rotationally driven to a first side in a circumferential direction around a central axis by the gas flowing while expanding from an outside to an inside in a radial direction, a diffuser disposed on a first side in an axial direction with respect to the scroll casing and forming a flow path of the gas discharged from the impeller to the first side in the axial direction and swirling to the first side in the circumferential direction, and a vortex preventer provided in the diffuser, in which the vortex preventer includes a profile rectifying blade portion, which is curved or inclined to a second side in the circumferential direction from the first side toward a second side in the axial direction, at least in a portion of the second side in the axial direction.