Laminated Header Branch Geometry for Uniform Refrigerant Distribution
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Solution Overview
Problem
Conventional laminated headers in heat exchangers experience uneven fluid distribution due to gravitational forces, leading to inefficient heat exchange performance as liquid fluid accumulates in certain branch passages, causing ununiform flow and reduced heat transfer efficiency.
Innovation Solution
A laminated header design featuring stacked flat-plate passages with progressively decreasing cross-sectional areas in branch passages, maintaining a flow speed of at least 0.3 m/s to counteract gravitational force effects and prevent liquid film accumulation, ensuring uniform fluid distribution across heat transfer tubes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional distributors with equal cross-sectional areas in branch passages are used, then the structure is simple and easy to manufacture, but gravitational forces cause uneven fluid distribution and liquid film accumulation in branch passages
Solution Approach 1:
The patent applies local quality by making each branch passage have a different cross-sectional area according to its position in the stacking direction. Specifically, branch passages closer to the upstream side have larger cross-sectional areas, while those closer to the downstream side have smaller cross-sectional areas. This localized variation in passage geometry compensates for gravitational effects and ensures uniform fluid distribution without requiring complex overall structural changes.
2Speed
If the cross-sectional area of downstream branch passages is reduced, then flow speed increases to counteract gravitational force, but the passage becomes more prone to liquid film accumulation
Solution Approach 1:
The patent applies parameter changes by systematically varying the cross-sectional area parameter of branch passages along the stacking direction. The cross-sectional area is adjusted as a continuous parameter that decreases from upstream to downstream branch passages. This parameter optimization maintains flow speed above the critical threshold (0.3 m/s) needed to prevent liquid film accumulation while avoiding excessive velocity that would cause other problems.
3Ease of manufacture
If uniform cross-sectional areas are used in all branch passages, then manufacturing is easier, but heat exchange performance degrades due to ununiform fluid distribution
Solution Approach 1:
The patent applies local quality by making each branch passage have a different cross-sectional area according to its position in the stacking direction. Specifically, branch passages closer to the upstream side have larger cross-sectional areas, while those closer to the downstream side have smaller cross-sectional areas. This localized variation in passage geometry compensates for gravitational effects and ensures uniform fluid distribution without requiring complex overall structural 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
This design enhances the uniformity of fluid distribution and reduces the impact of gravitational forces, thereby improving the heat exchange performance by maintaining a stable flow speed and preventing liquid film accumulation, resulting in improved cooling and heating efficiency.
Implementation Method 1
When the conventional distributor is used in such a state that the gravitational force applies in the branching direction of branch passages, a larger amount of liquid fluid flows to one of the branch passages
Data Source
AI summary
A laminated header includes: a first passage plate having a flat-plate shape in which a first passage is formed; a second passage plate having a flat-plate shape in which a plurality of second passages are formed; a third passage plate having a flat-plate shape in which a plurality of third passages are formed; a first branch passage plate having a flat-plate shape in which an upstream side branch passage is formed, the upstream side branch passage branching the first passage into the plurality of second passages; and a second branch passage plate having a flat-plate shape in which a downstream side branch passage is formed, the downstream side branch passage branching one of the plurality of second passages into the plurality of third passages.