Condenser Tube Geometry to Prevent Brazing-Induced Passage Clogging
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Solution Overview
Problem
Conventional condensers face challenges in improving heat radiation performance while avoiding clogging issues due to the distribution of brazing material in the refrigerant passages, particularly when the height of the inside space of the tube is reduced, leading to a smaller cross-sectional area and potential blockages.
Innovation Solution
A condenser design where the width of sub-passages and the refrigerant passage height are optimized, with the brazing material covering the inner walls and fins, adhering to specific relationships to prevent clogging while maintaining high heat radiation performance, such as Lp−t≧0.03Tr+0.22 and 0.005≦S/L<0.5, ensuring efficient refrigerant flow and heat exchange.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the height of the inside space of the tube is reduced to increase the total number of tubes and improve heat radiation performance, then the heat radiation performance is improved, but the cross-sectional area of the passage becomes small causing brazing material to be throughly distributed and potentially clog the passage
Solution Approach 1:
The patent applies parameter changes by establishing specific mathematical relationships between the passage width (Lp), refrigerant passage height (Tr), and fin plate thickness (t). The formulas Lp−t≧0.03Tr+0.22 and Lp−t≦0.115Tr2−1.14Tr+2.35 define optimal parameter ranges that prevent brazing material clogging while maintaining heat radiation performance. This quantitative parameter optimization resolves the contradiction by finding the precise balance point between passage dimensions and brazing material distribution.
2Quantity of substance
If the cross-sectional area of the passage is reduced to increase the total number of tubes, then more tubes can be stacked, but brazing material may be throughly distributed causing clogging
Solution Approach 1:
The patent uses parameter changes to control brazing material distribution by defining the relationship Lp−t≧0.03Tr+0.22, which ensures sufficient passage width relative to fin thickness and passage height. This parameter optimization allows increased tube density while preventing brazing material from being throughly distributed, thus resolving the contradiction between quantity of tubes and harmful brazing material distribution.
Solution Approach 2:
The patent applies the skipping principle by having brazing material selectively deposit on the fin surface and inner wall surface rather than being throughly distributed throughout the passage. The controlled brazing process rushes through the joining operation while skipping the harmful through distribution, achieving secure fin-to-tube attachment without clogging.
3Productivity
If the center-to-center pitch between passages is reduced to increase total wet edge length, then heat radiation performance is improved, but the passage cross-sectional area becomes smaller increasing clogging risk
Solution Approach 1:
The patent applies parameter changes by establishing the relationship Lp−t≦0.115Tr2−1.14Tr+2.35, which defines the upper limit of passage width based on passage height. This allows optimization of the center-to-center pitch between passages to increase total wet edge length for improved heat radiation performance, while simultaneously controlling the passage cross-sectional area to prevent clogging. The quadratic relationship provides precise manufacturing guidance.
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 optimized design achieves a heat radiation performance ratio of 90% or higher while preventing clogging, ensuring efficient refrigerant flow and maintaining the structural integrity of the condenser by controlling the distribution of brazing material within the specified parameters.
Implementation Method 1
At least one of an inner wall surface of each of the plurality of tubes and a surface of each corresponding one of the plurality of fins placed in the tube is covered with a brazing material
Implementation Method 2
Each of the plurality of tubes forms a refrigerant passage therein to conduct refrigerant and is adapted to exchange heat between the refrigerant, which is in gas phase and is conducted through the refrigerant passage, and external fluid, which flows outside of the tube, to cause condensation of the refrigerant in the gas phase into the refrigerant in liquid phase in the tube
Data Source
AI summary
Each tube and a corresponding fin satisfy all of the following relationships: Lp−t≧0.03Tr+0.22; Lp−t≦0.115Tr2−1.14Tr+2.35; and Lp−t≧5Tr2−8.3Tr+3, where Lp denotes a width of a sub-passages, Tr denotes a refrigerant passage height, and t denotes a plate thickness of the fin. The amount of a brazing material, which is present through an entire extent of the width of the sub-passage, is set to satisfy a relationship of 0.005≦S/L<0.5, where S denotes a size of a cross-sectional area of the brazing material, and L denotes a length of a center line of a corresponding portion of the fin, which is present through the entire extent of the width of the sub-passage.