Radial Fan Rotor With Double Curvature Guide Surface

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Solution Overview

Problem

Radial fans face challenges in achieving efficient flow-head curves while maintaining limited dimensions and reducing energy consumption, noise, and fluid dynamic efficiency, particularly for condensation boilers, and require improved performance across a wide range of flow modulation.

Innovation Solution

The design incorporates a rotor with specifically shaped main and auxiliary blades, a housing configuration, and damping mechanisms to optimize fluid dynamics and reduce energy absorption, featuring a guide surface with double curvature and a support ring to minimize turbulence and enhance performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the rotor dimensions are reduced to achieve compact fan size, then the overall dimensions are limited, but the fluid dynamic efficiency and head generation capability deteriorate

Engineering Contradiction:
Improverotor volumeVSAvoidfluid dynamic efficiency
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent applies parameter changes by optimizing the geometric parameters of the rotor blades, specifically the wrap angle (30°-50°), the ratio of outer rotor circumference to inner blade circumference (3.5-5.5), and the ratio of rotor diameter to axial height (7-7.5). These parameter optimizations enable compact rotor dimensions while maintaining high fluid dynamic efficiency and head generation capability, resolving the contradiction between size reduction and performance preservation

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs curved blade profiles with specific geometric characteristics, including arcs of circles with constant radius of curvature for both main blades and splits. This curvature optimization improves fluid flow characteristics and reduces turbulence, enabling efficient operation in a compact rotor volume without sacrificing fluid dynamic performance

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Use of energy by moving object

If the rotor blade configuration is optimized to improve fluid dynamic efficiency, then energy consumption is reduced, but the device complexity increases

Engineering Contradiction:
Improveenergy consumptionVSAvoidrotor structure complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The rotor is segmented into main blades and auxiliary blades (splits) that alternate around the rotation axis. This segmentation allows each blade type to be optimized for specific flow conditions, improving overall fluid dynamic efficiency and reducing energy consumption. The segmented design also facilitates modular manufacturing and assembly, partially offsetting the complexity increase

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the rotor blades are given different geometric properties - the main blades have specific wrap angles and curvature radii optimized for primary air movement, while the auxiliary blades have different dimensions optimized for flow control and turbulence reduction. This local quality differentiation improves energy efficiency without requiring complete redesign of the entire rotor structure

Inventive Principle:
Principle #3Local quality

3Stress or pressure

If the number of rotor blades is increased to improve head generation, then the static pressure increase is enhanced, but the energy absorption and noise increase

Engineering Contradiction:
Improvestatic pressure increaseVSAvoidnoise and energy absorption
Core Design Contradiction:
Stress or pressureVSObject-generated harmful factors

Solution Approach 1:

The auxiliary blades (splits) act as intermediaries between the main blades, providing flow control and turbulence reduction. These intermediate elements help convert chaotic turbulent flow into more ordered flow patterns, enabling high static pressure generation with fewer main blades, thereby reducing noise and energy absorption associated with excessive blade counts

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The curved profiles of both main blades and auxiliary blades, with specifically optimized radius of curvature, improve the smoothness of fluid flow through the rotor. This curvature optimization reduces flow separation and turbulence, enabling effective pressure generation without the need for excessive blade numbers that would increase noise and energy consumption

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 solution enables radial fans to achieve efficient flow-head curves with reduced energy consumption and compact dimensions, maintaining high performance across varying flow rates and pressures, while minimizing noise and energy absorption.

Implementation Method 1

a guide surface with double curvature and a support ring to minimize turbulence and enhance performance

Methodology Applied
Scientific EffectFluid dynamics:

Implementation Method 2

The air enters the housing through the suction aperture in the axial direction, crosses the rotor and is discharged from it in the radial direction

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP2921712B1A rotor for a radial fan and a radial fan
Publication Date: 2019.11.20 ELICA SPA
  • EP2921712B1 patent drawingFigure 1~2
  • EP2921712B1 patent drawingFigure 3~4
  • EP2921712B1 patent drawingFigure 5~6

AI summary

A rotor (2) for a radial fan (1) comprises a plurality of main blades (25) positioned in sequence around a rotation axis (A) and a hub element (36) forming a guide surface (51) from which the main blades (25) project, wherein the guide surface (51) is a rotational surface with respect to the rotational axis (A) with a generatrix forming a convex radially inner portion (52), a concave intermediate portion (53), and, possibly, a substantially rectilinear radially outer portion (54) forming an outer ring that is planar and orthogonal to the rotational axis A.