Heat exchanger comprising a device for distributing a liquid/gas mixture
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Heat exchangers face performance degradation due to non-uniform distribution of liquid and gaseous phases in two-phase mixtures, leading to varying temperature profiles and inefficient heat exchange, especially when the mixing device is prone to heat exchange with adjacent fluids, requiring complex restructuring or increased size to maintain uniformity.
Innovation Solution
A heat exchanger design with a heat exchange structure divided into portions, where one portion has a lower heat exchange coefficient than the main portion, positioned adjacent to the mixing device to minimize pre-vaporization of the liquid phase, ensuring uniform phase distribution without increasing the exchanger's size or complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the mixing device is placed in a passage adjacent to circulating fluid, then the liquid and gaseous phases can be mixed inside the exchanger, but heat exchange with the circulating fluid causes pre-vaporization of the liquid phase, leading to non-uniform phase distribution
Solution Approach 1:
The heat exchange structure is divided into zones with different properties: a first zone with standard heat exchange coefficient and a second zone with reduced heat exchange coefficient positioned adjacent to the mixing device. This local differentiation allows the mixing function to operate without excessive heat transfer that would cause pre-vaporization, while other parts of the exchanger maintain efficient heat exchange.
Solution Approach 2:
The patent modifies the heat exchange coefficient parameter in the vicinity of the mixing device by adjusting the density of the heat exchange structure (reducing it in the second zone). This parameter change reduces heat transfer in the critical mixing zone, preventing pre-vaporization and ensuring uniform phase distribution, while maintaining adequate heat exchange in other zones.
2Manufacturing precision
If the mixing device is placed in a zone with no circulating fluid, then pre-vaporization is minimized, but the exchanger structure must be restructured and its size increased
Solution Approach 1:
Instead of isolating the mixing device in a separate zone with no circulating fluid, the patent creates a localized modification within the existing fluid circulation path. The second zone with reduced heat exchange coefficient is positioned specifically adjacent to the mixing device, allowing the mixing operation to occur within the normal exchanger structure without increasing overall size.
Solution Approach 2:
The heat exchange structure is segmented into different zones along the longitudinal axis: a first zone with standard heat exchange properties and a second zone with reduced heat exchange properties. This segmentation allows the mixing device to function within the circulated fluid while the localized structural modification prevents excessive heat transfer only where needed.
3Productivity
If the heat exchange structure density is increased, then heat exchange efficiency is improved, but the risk of pre-vaporization in the mixing zone increases
Solution Approach 1:
The heat exchange structure employs different densities in different zones: a higher density in the first zone for efficient heat exchange and a lower density in the second zone adjacent to the mixing device to prevent pre-vaporization. This local quality differentiation resolves the contradiction between overall heat exchange efficiency and local phase distribution uniformity.
Solution Approach 2:
Rather than uniformly increasing heat exchange structure density throughout the exchanger, the patent applies the increased density only in the first zone where efficient heat exchange is needed, while maintaining lower density in the second zone where pre-vaporization would be harmful. This partial application of the structural enhancement avoids the negative effects while retaining the benefits where appropriate.
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 achieves uniform distribution of the liquid and gaseous phases, reducing heat transfers to the mixing device and maintaining mechanical strength, thereby enhancing the heat exchanger's performance and efficiency without complicating the structure or increasing its size.
Implementation Method 1
Heat exchanges between fluids can take place with or without phase change
Implementation Method 2
Heat exchange structure divided, along the longitudinal axis z, into at least a first portion and a second portion juxtaposed along the longitudinal axis
Implementation Method 3
the liquid phase supplying the mixing device is then inevitably in a situation of heat exchange with the circulating fluid(s) circulating in the adjacent passages, which can lead to the start of vaporization of the liquid phase
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
The invention relates to a plate heat exchanger (1) comprising a first series of passages (10) for carrying at least one refrigerant (F1) and a second series of passages (20) for carrying at least one thermogenic fluid (F2), each passage (10, 20) being defined between two consecutive plates (2) and extending parallel to a longitudinal axis (z), at least one mixing device (3) arranged in at least one passage (10) of the first series, the mixing device (3) being configured to receive a liquid phase (61) and a gaseous phase (62) of the refrigerant (F1) and to distribute a mixture of said phases (61, 62) in the at least one passage (10). According to the invention, at least one passage (20) of the second series adjacent to the at least one passage (10) of the first series comprises a heat exchange structure divided, along the longitudinal axis (z), into at least one first portion (100) and one second portion (200) juxtaposed along the longitudinal axis (z), the second portion (200) extending opposite at least one portion of the mixing device (3) and being configured so as to have a lower heat-exchange coefficient than the heat-exchange coefficient of the first portion (100).