Microchannel Heat Exchanger Fluid Distributor for Uniform Phase Flow
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Solution Overview
Problem
Mal-distribution of working fluid phases in microchannel heat exchangers, particularly with vertical headers, leads to thermal imbalances and reduced heat transfer efficiency due to vapor-liquid separation, affecting overall system performance.
Innovation Solution
A fluid distributor with features such as a distribution tube, supply tube, and optional components like flow restrictors, swirl generators, and baffles, designed to uniformly mix and distribute fluid phases across microchannel tubes, enhancing thermal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a vertical header is used in microchannel heat exchanger, then structural simplicity is improved, but fluid distribution uniformity deteriorates due to vapor-liquid separation
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 by confining fluid flow paths within dedicated compartments, thereby maintaining uniform fluid distribution while preserving structural simplicity.
Solution Approach 2:
A distribution tube extending through the partition walls acts as an intermediary component that connects the supply tube compartment to the return tube compartment. This distribution tube with radially arranged cavities ensures uniform fluid distribution to multiple microchannel tubes, mediating between the simple vertical header structure and the requirement for uniform phase distribution.
2Device complexity
If simple direct fluid supply is used, then device complexity is reduced, but heat transfer efficiency deteriorates due to phase mal-distribution
Solution Approach 1:
The distribution system is segmented into supply tube, distribution tube with multiple cavities, and return tube, each with specific functions. This segmentation enables controlled fluid distribution to multiple microchannel tubes, ensuring uniform phase distribution and maintaining high heat transfer efficiency without excessive complexity.
Solution Approach 2:
Different parts of the distribution system have specialized structures: the supply tube compartment receives fluid, the distribution tube has radially arranged cavities for uniform distribution, and the return tube collects fluid. This local quality optimization ensures efficient heat transfer at each location while maintaining overall system simplicity.
3Stability of the object's composition
If flow restrictor with small opening is used, then fluid distribution uniformity is improved, but pressure loss increases
Solution Approach 1:
Instead of using a single flow restrictor with small opening, the system segments the flow path into multiple cavities in the distribution tube. Each cavity provides a flow path, distributing the flow restriction across multiple parallel paths. This reduces the pressure drop while maintaining uniform fluid distribution to all microchannel tubes.
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 by minimizing phase separation and ensuring consistent fluid flow across all microchannel tubes.
Implementation Method 1
the swirl generator is configured to cause the working fluid, supplied by the supply tube, to move in a swirl motion
Implementation Method 2
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
Data Source
Figure 1A
Figure 1B
Figure 1C~1D
AI summary
A fluid distributor (100) for a heat exchanger is disclosed. The fluid distributor (100) comprises a header (102) having compartments (104). A plurality of MCHX tubes (108) associated with a heat exchange section of the heat exchanger are fluidically connected to at least one of the compartments (104). The fluid distributor (100) further comprises a distribution tube (110) extending longitudinally along the compartments (104) through the walls (106). The distribution tube (110) comprises a plurality of cavities (112) extending longitudinally along the length of the distribution tube and configured radially around a central axis (A-A') of the distribution tube (110). Each cavity (112) comprises ports (P) opening in a compartment (104). Further, the fluid distributor (100) comprises a supply tube (114) fluidically connected to the distribution tube (110) or to a supply tube compartment (104-1) of the header (102) and configured to supply a fluid into the distribution tube (110).