Axial Impeller Blade Geometry for Refrigeration Efficiency

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Solution Overview

Problem

Existing axial flow fans in refrigeration systems face challenges in achieving reduced bulk, weight, manufacturing ease, cost-effectiveness, high fluido-dynamic efficiency, and noiselessness simultaneously.

Innovation Solution

The design of an axial impeller with symmetrically connected blades, featuring specific geometric parameters such as blade angles, skew, and wrap angles, which are optimized for reduced noise and enhanced fluido-dynamic efficiency, allowing for easy manufacturing and reduced dimensions while maintaining efficient flow conveyance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional axial flow fan design is used, then manufacturing ease and cost effectiveness are achieved, but fluido-dynamic efficiency and noiselessness are insufficient

Engineering Contradiction:
Improvemanufacturing easeVSAvoidfluido-dynamic efficiency
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies parameter changes by optimizing specific geometric parameters of the impeller blades, including the angle of inclination (27°-35°), wrap angle (40°-60°), and skew (5°-15°). These parameter optimizations enhance the fluido-dynamic efficiency and reduce noise while maintaining manufacturing ease through standardized geometric definitions that can be easily fabricated.

Inventive Principle:
Principle #35Parameter changes

2Volume of moving object

If impeller dimensions are reduced, then bulk and weight are minimized, but maintaining efficient flow conveyance becomes difficult

Engineering Contradiction:
ImprovebulkVSAvoidflow conveyance efficiency
Core Design Contradiction:
Volume of moving objectVSProductivity

Solution Approach 1:

The patent maintains efficient flow conveyance in a compact design by optimizing the blade geometry parameters. The specific combination of inclination angle (27°-35°), wrap angle (40°-60°), and skew (5°-15°) allows the impeller to achieve high fluid movement efficiency even with reduced dimensions, effectively resolving the contradiction between compact size and conveyance performance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs curved blade surfaces and optimized edge geometries (rounded leading edges, tapered trailing edges) to improve flow characteristics. These curved surfaces reduce flow separation and turbulence, maintaining efficient flow conveyance while minimizing the overall impeller bulk and weight.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Reliability

If blade geometry is optimized for high efficiency, then fluido-dynamic performance improves, but manufacturing complexity increases

Engineering Contradiction:
Improvefluido-dynamic efficiencyVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent resolves the contradiction between high efficiency and manufacturing simplicity by defining blade geometry through a limited set of optimized parameters (inclination angle, wrap angle, skew) that can be easily manufactured. The standardized parameter ranges allow for simple fabrication processes while achieving superior fluido-dynamic performance.

Inventive Principle:
Principle #35Parameter changes

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 impeller achieves high fluido-dynamic efficiency, reduced noise, and ease of manufacturing with minimized weight and dimensions, making it suitable for conveying cooling flows in refrigeration systems effectively.

Implementation Method 1

an overpressure is generated on the front surface 4, while a fluido-dynamic depression is generated on the back surface 5

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

During a rotation of the impeller 1 in the 'forward' direction of rotation (arrow 12), an overpressure is generated on the front surface 4, while a fluido-dynamic depression is generated on the back surface 5

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Data Source

PatentEP2642130B1Impeller for axially conveying fluids, particularly for refrigeration systems
Publication Date: 2019.04.17 ELICA SPA
  • EP2642130B1 patent drawingFigure 1
  • EP2642130B1 patent drawingFigure 2~3
  • EP2642130B1 patent drawingFigure 4

AI summary

An axial impeller (1) for conveying fluids comprises a hub (3) and a plurality of blades (2) and, when seen in a projection on a plane normal to a rotation axis (R) of the impeller: - a leading edge (8) of the blades is substantially rectilinear and extends in a direction radial to the rotation axis (R), - an apical edge (7) of the blades is shaped like an arc of circle concentric to the rotation axis (R), - a trailing edge (9) of the blades has a curved and concave shape with a wrap angle (28) that increases from the intermediate radius (25) up to close to the outer radius (13).