Micro-Channel Heat Exchanger Inlet Tube for Uniform Refrigerant Flow
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Solution Overview
Problem
Micro-channel heat exchangers face inefficiencies due to uneven refrigerant fluid distribution, resulting from bi-phase refrigerant conditions that lead to stratified gas-liquid flow, causing some tubes to receive more fluid flow than others, which hinders overall performance.
Innovation Solution
A distributor tube with non-circular openings, such as slots, is used within the inlet manifold of micro-channel heat exchangers, where the openings are angularly arranged relative to the tube's longitudinal direction, improving refrigerant distribution uniformity by blending gas-phase and liquid-phase refrigerant and directing flow at an angle to ensure even distribution across all tubes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional inlet manifold is used in a micro-channel heat exchanger, then the structure is simple, but the refrigerant fluid distribution becomes uneven due to bi-phase stratification
Solution Approach 1:
The inlet manifold is segmented into multiple distribution zones along its length, with each zone having openings at specific positions and angles to serve different tube groups. This segmentation allows independent control of refrigerant distribution to different regions, achieving uniform flow distribution without complex overall restructuring.
Solution Approach 2:
Different sections of the inlet manifold are equipped with openings having different characteristics (positions, angles, sizes) tailored to local requirements. For example, tubes at different locations receive refrigerant from openings optimized for their specific flow needs, ensuring each local region achieves optimal distribution uniformity.
2Manufacturing precision
If circular openings are used in the distributor tube, then the manufacturing is simple, but the refrigerant distribution uniformity across tubes is insufficient
Solution Approach 1:
The patent employs non-circular opening shapes (such as rectangular or slot-shaped openings) instead of symmetric circular openings. These asymmetric shapes create specific flow patterns that improve refrigerant distribution uniformity across the tubes, particularly in preventing edge effects and promoting even flow division.
3Manufacturing precision
If the openings are arranged parallel to the tube axis, then the structure is simple, but the refrigerant flow distribution to edge tubes is insufficient
Solution Approach 1:
The openings are arranged at asymmetric angles relative to the tube axis rather than parallel alignment. This angular arrangement creates flow vectors that direct refrigerant more effectively toward edge tubes, compensating for the natural tendency of flow to concentrate in central tubes and achieving more uniform distribution.
Solution Approach 2:
The opening arrangement extends from a simple linear pattern into a two-dimensional angular configuration. By introducing angular variation as an additional dimension of control, the system can direct flow in multiple directions to reach different tube groups effectively, improving overall distribution uniformity.
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 enhances refrigerant distribution uniformity and operational efficiency by preventing stratification, ensuring consistent fluid flow to each micro-channel, thereby improving heat transfer and cooling performance in applications like air conditioning and refrigeration.
Implementation Method 1
a bi-phase refrigerant condition often exists between the inlet manifold of the heat exchanger and the tubes and micro-channels in parallel flow heat exchanger designs. That is, a two-phase fluid enters the inlet manifold of the heat exchanger and certain tubes receive more liquid-phase fluid flow while other tubes receive more gas-phase fluid flow
Implementation Method 2
an airflow is passed over the surface of the heat exchanger and a refrigerant fluid is passed through the tubes and micro-channels of the heat exchanger to absorb heat from the airflow
Data Source
AI summary
A micro-channel heat exchanger includes an inlet manifold fluidly connected with an outlet manifold by a plurality of generally parallel tubes, further defining a plurality of generally parallel micro-channels therethrough. Refrigerant is introduced to the heat exchanger through a distributor tube disposed within the inlet manifold. The distributor tube includes a plurality of non-circular openings disposed along the length thereof which act as an outlet for refrigerant flow into the inlet manifold and eventually into and through the tubes and micro-channels. The openings are preferably slots arranged along the length of the distributor tube at an angle relative to the longitudinal direction of the distributor tube and oriented within the inlet manifold for a general direction of refrigerant flow at an angle relative to the general direction of refrigerant flow through the tubes. Alternative shapes for the openings are also considered.