Laminated Header Flow Layout for Uniform Refrigerant Distribution

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Solution Overview

Problem

In laminated headers for heat exchangers, refrigerant distribution is nonuniform due to concentration in branching passages, leading to reduced heat exchange performance as refrigerant is not evenly supplied to heat transfer tubes.

Innovation Solution

The design incorporates a distribution flow passage system with straight and branching passages that allow refrigerant to flow in opposite directions, preventing concentration and ensuring uniform distribution by maintaining a certain length for straight portions, optimizing the L/D ratio to enhance rectification and reduce pressure loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If refrigerant flows through conventional branching flow passages, then the laminated header can be compact, but liquid refrigerant concentrates in the distribution flow passages leading to nonuniform distribution

Engineering Contradiction:

Improvesize of laminated headerVSAvoiduniformity of refrigerant distribution

Core Design Contradiction:

Volume of moving objectVSManufacturing precision

Solution Approach 1:

The distribution flow passage is segmented into multiple straight passages (first passage, second passage, third passage) with alternating flow directions. This segmentation prevents liquid refrigerant concentration by dividing the flow path into discrete sections, each maintaining uniform flow characteristics.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention inverts the conventional single-direction branching approach by implementing alternating flow directions in successive passages. Refrigerant flows in opposite directions in adjacent passages, which prevents liquid concentration and ensures uniform distribution to all outlets.

Inventive Principle:

Principle #13The other way round (Inversion)

2Volume of moving object

If straight portions of distribution flow passage are shortened to reduce size, then the laminated header becomes more compact, but refrigerant concentration occurs leading to poor distribution

Engineering Contradiction:

Improvesize of laminated headerVSAvoidheat exchange performance

Core Design Contradiction:

Volume of moving objectVSProductivity

Solution Approach 1:

The invention creates a dynamic flow pattern where refrigerant alternates direction in successive passages. This dynamic approach allows the system to maintain effective distribution with shorter straight portions, as the alternating flow prevents liquid accumulation that would otherwise require longer straight sections to resolve.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention changes the flow direction parameter in alternating passages, creating a pattern where adjacent passages have opposite flow directions. This parameter change enables compact dimensions while maintaining distribution uniformity, as the direction alternation prevents liquid concentration without requiring long straight portions.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If conventional branching passages are used, then the structure is simple, but refrigerant distribution ratio becomes nonuniform reducing heat exchange efficiency

Engineering Contradiction:

Improvestructure of distribution flow passageVSAvoidheat exchange performance

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The distribution flow passage is divided into multiple segmented sections (first passage, second passage, third passage) with defined flow directions. This segmentation provides a systematic approach to achieving uniform distribution while maintaining structural clarity and manufacturability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention introduces directional inversion in alternating passages, creating a simple yet effective pattern that ensures uniform refrigerant distribution. This inverted approach in successive passages maintains structural simplicity while dramatically improving distribution reliability and heat exchange performance.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS10060685B2Laminated header, heat exchanger, and air-conditioning apparatus

Publication Date: 2018.08.28 MITSUBISHI ELECTRIC CORP

AI summary

A laminated header includes: a plurality of plate-like members laminated with each other; one first opening; a plurality of second openings; and a distribution flow passage connecting the one first opening and each of the plurality of second openings to each other. The distribution flow passage includes: a first passage having a straight line shape; a first branching flow passage for the first passage to branch into a plurality of passages; a second passage that has a straight line shape and is connected to each of the plurality of passages branched in the first branching flow passage; a second branching flow passage for the second passage to branch into a plurality of passages; and a third passage that has a straight line shape and is connected to each of the plurality of passages branched in the second branching flow passage.