Laminated Header Branching for Uniform Refrigerant Distribution

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Solution Overview

Problem

The existing stacking-type headers suffer from low uniformity in refrigerant distribution when the inflow direction is not parallel to the gravity direction, leading to deficiencies or excesses in refrigerant flow due to gravitational effects.

Innovation Solution

The proposed stacking-type header design includes a branching flow passage with specific configurations, such as varying flow passage heights and widths, to equalize flow resistance between different paths, ensuring uniform refrigerant distribution by minimizing differences in flow rates through point symmetry and optimized flow passage geometries.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the branching flow passage is designed with point symmetry and equal flow-passage resistance, then the structural simplicity is maintained, but the uniformity in refrigerant distribution deteriorates due to gravity effects

Engineering Contradiction:
Improvebranching flow passage structureVSAvoiduniformity in refrigerant distribution
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent applies asymmetry by intentionally designing the first and second flow passages with different geometries despite point symmetry about the opening port. The first flow passage has a larger flow-passage area than the second flow passage, creating asymmetric flow resistance characteristics that compensate for gravitational effects on refrigerant flow distribution

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent changes the flow-passage resistance parameter between the first and second flow passages. By making the flow-passage resistance in the first flow passage larger than in the second flow passage, the design compensates for gravity-induced flow imbalances and achieves uniform refrigerant distribution across all branching directions

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If the flow-passage resistance in the first flow passage is made larger than in the second flow passage, then the uniformity in refrigerant distribution is improved, but the flow resistance difference increases

Engineering Contradiction:
Improveuniformity in refrigerant distributionVSAvoidflow resistance difference
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful effect of flow resistance differences into a beneficial feature. By intentionally creating asymmetric flow resistance between the first and second flow passages, the design uses the resistance difference to counteract gravitational effects, transforming what would normally be a source of non-uniform distribution into a mechanism that promotes uniform refrigerant distribution

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

This design enhances the uniformity of refrigerant distribution, reduces the impact of gravity on flow rates, and maintains consistent refrigerant flow even when the header is installed at an angle, improving overall refrigerant distribution efficiency.

Implementation Method 1

the branching flow passage is smaller in difference in flow resistance between the first flow passage and the second flow passage

Methodology Applied
Scientific EffectFlow resistance: Pressure Drop

Implementation Method 2

when the stacking-type header is used under a state in which the inflow direction of the refrigerant flowing into the branching flow passage is not parallel to the gravity direction, the refrigerant may be affected by the gravity

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP3018441B1Laminated header, heat exchanger, and air conditioning device
Publication Date: 2019.07.24 MITSUBISHI ELECTRIC CORP
  • EP3018441B1 patent drawingFigure 1~2
  • EP3018441B1 patent drawingFigure 3~5(b)
  • EP3018441B1 patent drawingFigure 6~7

AI summary

A stacking-type header (2) according to the present invention includes: a first plate-shaped unit having a plurality of first outlet flow passages (11 A) formed therein; and a second plate-shaped unit (12) stacked on the first plate-shaped unit (11), the second plate-shaped unit (12) having a distribution flow passage (12A) formed therein, the distribution flow passage (12A) being configured to distribute refrigerant, which passes through a first inlet flow passage (12a) to flow into the second plate-shaped unit (12), to the plurality of first outlet flow passages (11A) to cause the refrigerant to flow out from the second plate-shaped unit (12), in which the distribution flow passage (12A) includes a branching flow passage (12b) including: an opening port configured to allow the refrigerant to flow thereinto; a first flow passage communicating between the opening port and an end portion positioned on an upper side relative to the opening port; and a second flow passage communicating between the opening port and an end portion positioned on a lower side relative to the opening port, and in which the branching flow passage (12b) is smaller in difference in flow resistance between the first flow passage and the second flow passage than a branching flow passage in a state in which a flow-passage resistance in the first flow passage and a flow-passage resistance in the second flow passage are equal to each other, and in a state in which the first flow passage and the second flow passage are point symmetric with each other about the opening port.