Microchannel Heat Exchanger Fluid Distributor for Uniform Phase Mixing
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Solution Overview
Problem
Mal-distribution of working fluid phases in microchannel heat exchangers, particularly with vertical headers, leads to thermal inefficiencies due to vapor-liquid separation, resulting in reduced heat transfer coefficients and overall system performance.
Innovation Solution
A fluid distributor with a header, distribution tube, and supply tube system that includes flow restrictors, swirl generators, and baffle configurations to promote uniform mixing and distribution of fluid phases across microchannel tubes, enhancing thermal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a vertical header configuration is used in microchannel heat exchangers, then the structural simplicity and ease of manufacture are improved, but vapor-liquid separation occurs leading to mal-distribution of working fluid phases and reduced heat transfer efficiency
Solution Approach 1:
The header is segmented into multiple compartments separated by partition walls, with each compartment serving a specific function (supply tube compartment, distribution tube compartment, return tube compartment). This segmentation prevents vapor-liquid separation and ensures uniform fluid distribution to microchannel tubes while maintaining structural simplicity
Solution Approach 2:
A distribution tube with multiple cavities and ports acts as an intermediary component between the supply tube and microchannel tubes. The distribution tube receives working fluid from the supply tube and distributes it uniformly to multiple microchannel tubes, preventing mal-distribution and maintaining heat transfer efficiency
2Productivity
If flow restrictors and swirl generators are added to the fluid distributor, then uniform mixing and distribution of fluid phases is improved, but the device complexity increases
Solution Approach 1:
Flow restrictors are installed at specific locations (in the supply tube or between supply tube and distribution tube) rather than throughout the entire system. This localized approach achieves uniform fluid distribution while minimizing overall device complexity
Solution Approach 2:
A swirl generator is placed upstream of the distribution tube to pre-mix the working fluid before it enters the distribution tube. This preliminary mixing action ensures uniform phase distribution throughout the system without requiring complex mixing mechanisms in the distribution tube itself
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 solution achieves more uniform distribution of working fluid phases, improving heat transfer efficiency and capacity in microchannel heat exchangers by minimizing phase separation and ensuring consistent fluid flow across all tubes.
Implementation Method 1
a flow restrictor configured within the supply tube or between the supply tube and the distribution tube, wherein the flow restrictor is an annular member having a central opening that is configured in line with the distribution tube and having a predefined gap therebetween
Implementation Method 2
a swirl generator configured upstream of the distribution tube or within the supply tube, wherein the swirl generator is configured to cause the working fluid, supplied by the supply tube, to move in a swirl motion
Implementation Method 3
a distribution tube extending longitudinally along the compartments of the header through the walls, wherein the distribution tube comprises a plurality of cavities extending longitudinally along a length of the distribution tube and configured radially around a central axis of the distribution tube
Data Source
AI summary
A fluid distributor for a heat exchanger is disclosed. The fluid distributor comprises a header having compartments. A plurality of MCHX tubes associated with a heat exchange section of the heat exchanger are fluidically connected to at least one of the compartments. The fluid distributor further comprises a distribution tube extending longitudinally along the compartments through the walls. The distribution tube comprises a plurality of cavities extending longitudinally along the length of the distribution tube and configured radially around a central axis of the distribution tube. Each cavity comprises ports opening in a compartment. Further, the fluid distributor comprises a supply tube fluidically connected to the distribution tube or to a supply tube compartment of header and configured to supply a fluid into the distribution tube.