Laminated Header Flow Paths for Uniform Two-Phase Flow
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Solution Overview
Problem
Maldistribution of two-phase flow at the inlet of heat exchange tubes in microchannel heat exchangers leads to uneven refrigerant distribution and variations in local heat transfer rates, particularly in vertical headers where gravity affects the mixing of liquid and vapor.
Innovation Solution
A laminated header design for microchannel heat exchangers, comprising stacked plates with specific bore-holes, cut-out sections, and slots, which ensures uniform fluid flow into microchannel tubes by maintaining consistent mass flow rates and preventing liquid separation under gravity, achieved through parallel stacking and brazing of plates to form a leak-proof connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional header design is used in microchannel heat exchangers, then the structure is simple to manufacture, but maldistribution of two-phase flow occurs leading to uneven refrigerant distribution and variations in local heat transfer rates
Solution Approach 1:
The header is divided into multiple laminated plates (first plate with inlet bore-hole, second plate with cut-out sections, third plate with bore-holes, fourth plate with cut-out sections, fifth plate with slots) that are stacked and brazed together. Each plate contributes specific flow distribution features, with the cut-out sections creating expanding chambers that promote uniform two-phase flow distribution to microchannel tubes while maintaining manufacturability through standardized plate components.
Solution Approach 2:
The invention transitions from a conventional single-volume header to a multi-layer laminated structure where flow distribution occurs across multiple dimensions. The stacked plates create three-dimensional flow paths with expanding chambers formed by cut-out sections, enabling uniform refrigerant distribution through vertical and horizontal flow expansion while maintaining a compact overall structure.
2Reliability
If a conventional header design is used, then the device complexity is low, but liquid and vapor separation occurs under gravity affecting heat transfer performance
Solution Approach 1:
The header is segmented into multiple laminated plates (first plate with inlet bore-hole, second plate with cut-out sections, third plate with bore-holes, fourth plate with cut-out sections, fifth plate with slots) that are stacked and brazed together. Each plate contributes specific flow distribution features, with the cut-out sections creating expanding chambers that promote uniform two-phase flow distribution to microchannel tubes while maintaining manufacturability through standardized plate components.
Solution Approach 2:
The invention transitions from a conventional single-volume header to a multi-layer laminated structure where flow distribution occurs across multiple dimensions. The stacked plates create three-dimensional flow paths with expanding chambers formed by cut-out sections, enabling uniform refrigerant distribution through vertical and horizontal flow expansion while maintaining a compact overall structure.
3Manufacturing precision
If a laminated header design with multiple plates and cut-out sections is implemented, then uniform fluid distribution and consistent mixing are achieved, but the manufacturing process becomes more complex
Solution Approach 1:
The header is divided into multiple laminated plates (first plate with inlet bore-hole, second plate with cut-out sections, third plate with bore-holes, fourth plate with cut-out sections, fifth plate with slots) that are stacked and brazed together. Each plate contributes specific flow distribution features, with the cut-out sections creating expanding chambers that promote uniform two-phase flow distribution to microchannel tubes while maintaining manufacturability through standardized plate components.
Solution Approach 2:
Multiple separate plate components are merged through brazing to form an integrated laminated header structure. The plates are stacked in a specific sequence and joined using brazing technology, combining the individual flow distribution features of each plate into a unified structure that achieves uniform refrigerant distribution while leveraging standardized manufacturing of individual plate components.
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 to microchannel tubes, maintaining consistent mixing of liquid and vapor, reducing pressure drop, and enhancing the overall performance and efficiency of the heat exchanger while being cost-effective and easy to manufacture.
Implementation Method 1
Maldistribution of two-phase flow at the inlet of heat exchange tubes in microchannel heat exchangers leads to uneven refrigerant distribution and variations in local heat transfer rates, particularly in vertical headers where gravity affects the mixing of liquid and vapor.
Implementation Method 2
the first plate, the second plate, the third plate, the fourth plate, and the fifth plate are parallelly stacked and brazed together to form the laminated header
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
A laminated header (100) for a microchannel heat exchanger comprises a first plate (102) comprising a first bore-hole (102-1), a second plate (104) comprising a first cut-out section (104-1), wherein a volume of the first cut-out section (104-1) along the length decreases in a direction away from the first bore-hole (102-1), a third plate (106) comprising a plurality of second bore-holes (106-1), a fourth plate (108) comprising a plurality of second cut-out sections (108-1), and a fifth plate (110) comprising a plurality of slots (S). The second plate (104) is parallel and between the first plate (102) and the third plate (106), and the fourth plate (108) is parallel and between the third plate (106) and the fifth plate (110). The first cut-out section (104-1) fluidically connects the first bore-hole (102-1) to each of the second bore-holes (106-1) and the second cut-out sections (108-1) fluidically connects the second bore-holes (106-1) to the second slots (S). The stacked header (100) is configured to fluidically connect the first bore-hole (102) to microchannel tubes (112).