Rotary Compressor Side Channel Design for Efficiency

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Solution Overview

Problem

Peripheral volumetric compressors face inefficiencies and leaks due to complex fluid dynamics, leading to suboptimal energy efficiency and limited commercial success compared to centrifugal compressors.

Innovation Solution

The compressor design features specific ratios of rotor to blade dimensions, non-planar blades, internal channel reliefs, and a separation piece to optimize fluid flow and compression, reducing leaks and enhancing efficiency by accelerating fluid movement tangentially and perpendicularly, with a third series of blades and through holes for axial pressure balance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If peripheral volumetric compressors use complex fluid dynamics design, then compression ratio increases, but energy efficiency decreases and leaks increase

Engineering Contradiction:
Improvecompression ratioVSAvoidenergy efficiency
Core Design Contradiction:
Stress or pressureVSLoss of energy

Solution Approach 1:

The compressor is divided into multiple independent peripheral channels (first, second, and optionally third channels) arranged around the rotor. Each channel processes fluid independently with its own inlet and outlet, allowing optimization of fluid flow paths and reducing interference between flows, thereby improving energy efficiency while maintaining compression ratio

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from two-dimensional planar blade designs to three-dimensional non-planar blades with specific curvature and orientation. The blades are arranged at specific angles relative to the rotor surface, creating three-dimensional fluid flow paths that reduce turbulence and improve compression efficiency while minimizing energy losses

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

2Productivity

If rotor speed is increased to improve productivity, then flow rate increases, but wear and friction increase

Engineering Contradiction:
Improveflow rateVSAvoidwear resistance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The compressor operates at optimized rotational speeds that balance productivity and reliability. The peripheral channel design and blade configuration allow efficient compression at moderate speeds, reducing mechanical wear while maintaining acceptable flow rates. The system dynamically adapts to different operating conditions through its geometric design rather than relying solely on speed increases

Inventive Principle:
Principle #15Dynamics

3Device complexity

If simple rotor design is used to reduce device complexity, then manufacturing cost decreases, but compression efficiency is insufficient

Engineering Contradiction:
Improvestructural simplicityVSAvoidcompression efficiency
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The rotor features localized geometric optimizations including non-planar blades with specific curvature, angled arrangements relative to the rotor surface, and precisely positioned inlet/outlet openings in the peripheral channels. These local geometric features enhance compression efficiency without requiring complex overall rotor architecture, maintaining manufacturing simplicity while improving performance

Inventive Principle:
Principle #3Local quality

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 design achieves an adiabatic efficiency of around 60% with a higher compression ratio and lower rotational speeds, reducing maintenance and installation costs, suitable for various gases and applications like natural gas production and biogas processing.

Implementation Method 1

the shape of the vanes of volumetric compressors was modified as well as that of the annular channel in order to improve the centrifugal effect

Methodology Applied
Scientific EffectCentrifugal effect: Centrifugal Force

Implementation Method 2

the motion imparted to the fluid is a relatively complex helical motion, which induces compression comparable to that of a multi-stage compressor

Methodology Applied
Scientific EffectHelical motion:

Implementation Method 3

said casing of said at least one peripheral channel and/or said static core has internal reliefs intended to modify the direction of the fluid which flows inside said peripheral channel

Methodology Applied
Scientific EffectFlow direction modification:

Implementation Method 4

These machines are intended to compress a fluid, in particular a gas, between an inlet opening (or inlet) and an outlet opening (or outlet) in the manner of a dynamic compressor

Methodology Applied
Scientific EffectVolumetric compression: Compression

Implementation Method 5

the rotor has a multiplicity of through holes intended to balance the induced axial pressures

Methodology Applied
Scientific EffectPressure balancing: Pressure Gradient

Data Source

PatentEP2825776B1Rotary compressor provided with at least one side channel
Publication Date: 2019.09.04 CHIAFFI MICHEL
  • EP2825776B1 patent drawingFigure 1~4
  • EP2825776B1 patent drawingFigure 5~6
  • EP2825776B1 patent drawingFigure 7

AI summary

The invention relates to a rotary compressor that includes a disc-shaped rotor having a radius R, supporting on the periphery thereof at least one first series of non-planar blades intended for accelerating the fluid to be compressed between an intake and an outlet, a casing defining on the outside at least one generally toroidal channel that is peripheral to the rotor, said at least one channel being coaxial, arranged at the radial end of said rotor and containing said blades, a static and annular core being arranged inside said at least one toroidal channel such as to define a free section A with said casing. According to the invention, the arrangements and respective shapes of the rotor, the at least one peripheral channel and said at least one series of blades are such that the ratio A/R2 is between 6% and 16%.