Truncated-Conical Flow Straightener for Lower Refrigerator Fan Pressure Loss

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Solution Overview

Problem

Conventional refrigerators face issues with increased pressure loss, reduced air volume, and noise due to the inefficient arrangement of cooling fans and flow straighteners, particularly in compact designs where the fan axis is inclined, leading to suboptimal cooling efficiency and uneven cooling distribution.

Innovation Solution

The arrangement of a rectangular axial flow fan with a truncated conical flow straightener, where the distance between the fan and the straightener is minimized, and the angle of the straightener's inclined part is limited to 20 degrees or less, reduces pressure loss and enhances air volume, ensuring effective cooling and low noise operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the rotary axis of cooling fan is inclined from horizontal direction to increase space on suction side, then space utilization is improved, but the clearance between flow straightener and cooling fan becomes uneven leading to increased pressure loss and reduced air volume

Engineering Contradiction:
Improvespace on suction sideVSAvoidpressure loss
Core Design Contradiction:
Volume of moving objectVSLoss of energy

Solution Approach 1:

The flow straightener is designed with an asymmetric structure where the clearance distance varies across different radial positions. Specifically, the clearance is smaller at positions where the fan blade tip is closer to the flow straightener and larger at positions where the fan blade tip is farther away. This asymmetric design compensates for the inclined fan axis configuration, maintaining optimal flow straightening effect across the entire fan discharge area and preventing excessive pressure loss.

Inventive Principle:
Principle #4Asymmetry

2Device complexity

If the plane part of duct is disposed in vertical direction, then structure is simplified, but the lower clearance between flow straightener and cooling fan is small while upper clearance is large, reducing pressure loss reduction effect

Engineering Contradiction:
Improveduct structureVSAvoidpressure loss
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The flow straightener is designed with locally varying clearance characteristics. The clearance distance from the flow straightener surface to the fan blade tip is adjusted at different radial positions and angular positions. This local optimization ensures that the flow straightening effect is maintained throughout the entire fan discharge area, preventing excessive pressure loss while keeping the duct structure simple.

Inventive Principle:
Principle #3Local quality

3Loss of energy

If the plane part of duct is disposed perpendicular to rotary axis to increase pressure reduction effect, then pressure loss is reduced, but space on cool air discharge side reduces and air volume reduces

Engineering Contradiction:
Improvepressure lossVSAvoidair volume
Core Design Contradiction:
Loss of energyVSVolume of moving object

Solution Approach 1:

The flow straightener design incorporates dynamic clearance adjustment through its geometric configuration. The clearance distance varies continuously across the fan discharge area, being smaller where needed for pressure reduction and larger where space is required for air volume. This dynamic design allows simultaneous optimization of both pressure loss reduction and air volume maintenance.

Inventive Principle:
Principle #15Dynamics

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

This configuration reduces pressure loss on the discharge side of the cooling fan, increases air volume, and enhances cooling efficiency while maintaining low noise levels, effectively cooling storage compartments and reducing power consumption.

Implementation Method 1

a flow straightener 8 that protrudes toward the cooling fan 5 so as to have a substantially truncated conical shape... in order to solve this problem, conically protruding flow straightener 6 is provided on a part facing cooling fan 105 of duct 107

Methodology Applied
Scientific EffectFlow straightening: Flow Separation

Implementation Method 2

axial flow or diagonal flow cooling fan 105 that circulates cool air generated by cooler 104 into storage compartment 103... cooling fan 33 that is an axial flow fan which rotates clockwise... uniformly radial discharge of cool air by cooling fan 67

Methodology Applied
Scientific EffectForced convection: Forced Convection

Implementation Method 3

cooler 104 is stored that is connected in series with a compressor (not shown), a condenser (not shown), and a decompressor (not shown), and configures a refrigerant circuit... cooler 32... cooling compartment 30 that generates cool air

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP2778577B1refrigerator
Publication Date: 2020.04.08 PANASONIC HOLDINGS CORP
  • EP2778577B1 patent drawingFigure 1
  • EP2778577B1 patent drawingFigure 2
  • EP2778577B1 patent drawingFigure 3

AI summary

The present invention includes a cooler stored on a back surface of a storage compartment, and a cooling fan (5) configured to circulate cool air generated by the cooler into the storage compartment, and further includes a duct (7) having a flow straightener (8) that protrudes toward the cooling fan (5) at such a position as to face the cooling fan (5). Furthermore, the flow straightener (8) is formed in a substantially truncated conical shape, the flow straightener (8) having an inclined part (9) and a plane part (10). Consequently, it is possible to reduce a pressure loss on a blowing side without increase in a pressure loss on a suction side of the cooling fan (5), while suppressing the depth dimension of the duct (7). Furthermore, it is possible to provide a refrigerator having high storage efficiency, high cooling efficiency, and low noise.