Fin Heat Exchanger Drainage Structure Around Flat Tubes
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Solution Overview
Problem
Existing fin-and-tube heat exchangers face poor drainage performance for water droplets adhering to the fin, leading to prolonged drainage times and reliability issues due to obstacles from heat transfer tubes, which also increase defrosting time and airflow resistance.
Innovation Solution
The heat exchanger incorporates protruding portions with one end in the cutout region and the other end in the drainage region, guiding water droplets from the cutout region to the drainage region, preventing stagnation on heat transfer tubes and ensuring reliable drainage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If heat transfer tubes are inserted into cutout portions of fins, then heat exchange performance is improved, but drainage performance deteriorates due to water droplets being blocked by the tubes
Solution Approach 1:
The patent introduces guide portions as intermediary structures that mediate between the cutout region and drainage region. These guide portions redirect water droplets away from heat transfer tubes, allowing both heat exchange and drainage functions to coexist effectively
Solution Approach 2:
The fin surface is segmented into distinct functional regions: cutout regions for heat transfer, drainage regions for water removal, and guide portions for water redirection. This segmentation allows each region to optimize its specific function without interfering with others
2Area of stationary object
If water droplets are blocked by heat transfer tubes, then heat exchange contact area is increased, but drainage time is prolonged
Solution Approach 1:
Different regions of the fin are assigned different qualities and functions: cutout regions maximize heat transfer, while drainage regions with guide portions prioritize water removal. The guide portions locally redirect water flow to prevent stagnation near heat transfer tubes
3Power
If water droplets stagnate on heat transfer tubes, then heat exchange efficiency is improved, but defrosting time increases
Solution Approach 1:
The guide portions perform preliminary action by redirecting water droplets away from heat transfer tubes before they can stagnate. This prevents the formation of ice layers that would require extended defrosting time, while still allowing sufficient water contact for heat exchange
4Power
If frost forms around heat transfer tubes, then heat exchange performance is improved initially, but airflow resistance increases
Solution Approach 1:
The patent extracts water droplets from the vicinity of heat transfer tubes using guide portions and directs them to dedicated drainage regions. This prevents frost formation around tubes, maintaining airflow channels open and reducing airflow resistance while preserving heat exchange performance
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 drainage performance by quickly guiding water droplets to the lower end, reducing stagnation, improving reliability, and shortening defrosting times, while maintaining airflow efficiency and resistance to frost formation.
Implementation Method 1
a water droplet adhering to a part above the cutout portion of the fin falls onto the upper surface of the heat transfer tube inserted into the cutout portion due to the gravity
Implementation Method 2
the heat exchanger exchanges heat between a fluid that causes heat exchange, such as air flowing between the fins, and a fluid subjected to heat exchange, such as water and refrigerant flowing through the heat transfer tubes
Implementation Method 3
The heat transfer tubes inserted into the cutout portions and the fin collars are bonded to each other by furnace brazing or with an adhesive
Implementation Method 4
The heat transfer tubes inserted into the cutout portions and the fin collars are bonded to each other by furnace brazing or with an adhesive
Implementation Method 5
when the heat exchanger operates as an evaporator, moisture in the air adheres to the heat exchanger as condensed water
Implementation Method 6
frost is formed from moisture in the air and adheres to the heat exchanger
Implementation Method 7
Air-conditioning apparatuses, refrigerating apparatuses, or other apparatuses including a heat exchanger perform a defrosting operation to melt frost adhering to the heat exchanger. The frost is melted into a water droplet
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A heat exchanger includes a fin having a plate shape and including a first region where a plurality of cutout portions are formed with intervals in a longitudinal direction that is a gravity direction, and a second region where the plurality of cutout portions are not formed in the longitudinal direction, and flat tubes attached to the plurality of cutout portions and intersecting the fin. Protruding portions protruding from a planar portion of the fin are formed on the fin, and the protruding portions each have a shape in which a first end is located in the first region and a second end is located in the second region and below the first end.