Laminated Header Stacking for Uniform Microchannel Refrigerant Flow
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Solution Overview
Problem
Maldistribution of refrigerant in microchannel heat exchangers leads to uneven heat transfer rates due to gravity-induced separation of liquid and vapor phases, particularly in vertical headers, necessitating an improved design for uniform fluid distribution.
Innovation Solution
A laminated header design comprising stacked plates with specific cut-out sections and bore-holes that form a fluidic passage, ensuring uniform flow distribution into microchannel tubes by maintaining consistent mass flow rates and minimizing pressure drop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional header design is used in microchannel heat exchangers, then the structure is simple, but refrigerant maldistribution occurs due to gravity-induced phase separation
Solution Approach 1:
The header is divided into multiple stacked plates (distribution plate, hole plate, section plate) with specific cut-out sections and bore-holes. This segmentation allows the refrigerant flow to be divided into multiple paths, preventing phase separation and ensuring uniform distribution to each microchannel tube while maintaining a manageable structural complexity through modular plate design
Solution Approach 2:
The patent introduces a vertical stacking dimension by arranging plates in a laminated configuration with flow paths extending in both horizontal and vertical directions. The fluidic passage extends from the inlet bore-hole through the distribution plate, through bore-holes in the hole plate, and into section plate cut-out sections, creating a three-dimensional flow distribution network that effectively manages phase separation
2Ease of manufacture
If the header structure is simplified, then manufacturing is easier, but pressure drop increases and flow distribution becomes uneven
Solution Approach 1:
Each plate in the stacked configuration is designed with specific local features: the distribution plate has a first cut-out section with a specific shape and size, the hole plate has multiple bore-holes with specific diameters and spacing, and the section plate has second cut-out sections. These localized optimizations ensure uniform flow distribution and control pressure drop while maintaining overall manufacturing simplicity through standardized plate fabrication processes
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 laminated header design ensures uniform fluid distribution, preventing maldistribution and maintaining consistent mixing of phases, thereby enhancing heat transfer efficiency and reducing manufacturing complexity and costs.
Implementation Method 1
The laminated header forms a fluidic passage that extends from the inlet bore-hole towards the plurality of slots while extending in a first direction along the longitudinal axis, between a top end and a bottom end, of the distribution plate and further extending from the first cut-out section into each of the second cut-out sections and the plurality of slots, via the plurality of bore-holes
Implementation Method 2
The distribution plate, the hole plate, and the section plate, are parallelly stacked between an inlet plate and a tube plate, and brazed together to form the laminated header, and wherein an end of the plurality of microchannel tubes of the heat exchanger is inserted within a plurality of slots of the tube plate and brazed to the laminated header to create a leak-proof connection
Data Source
AI summary
A laminated header for a microchannel heat exchanger comprises a distribution plate comprising a first cut-out section of a first shape extending along a longitudinal axis of the distribution plate, wherein a width of the first cut-out section at least partially decreases along the longitudinal axis a hole plate comprising a plurality of bore-holes formed therein and separated by a distance therebetween, a section plate comprising a plurality of second cut-out sections of a second shape different from the first shape, and wherein the hole plate is parallelly stacked between the distribution plate and the section plate. The first cut-out section fluidically connects with each of the bore-holes and the second cut-out sections fluidically connects the bore-holes to a plurality of microchannel tubes of the heat exchanger.