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Fin Types for Aluminum Plate Fin Heat Exchangers
2024-10-17 10:21:58
1: Definition of Aluminum Fins
Fins are the most basic components of plate-fin heat exchangers. The heat transfer process is mainly completed by fins, and only a part is completed directly by the partition.
The connection between the fins and the partition is perfect brazing, so most of the heat is transferred to the cold carrier through the fins and the partition.
Since the heat transfer of the fins is not direct heat transfer, the fins are also called "secondary surfaces".
The fins also play a reinforcing role between the two partitions. Although the fins and partitions are very thin, they have high strength and can withstand high pressure. The fins are stamped from very thin 3003 aluminum foil, and the thickness is generally from 0.15mm to 0.3mm.
2: Types of fins
Generally speaking, there are several types of fins:
● Plain fin
● Offset fin
● Perforated fin
● Wavy fin
● Louvered fin
2.1: Plain fin
Compared with other structural forms of fins, the straight fin has the characteristics of smaller heat transfer coefficient and flow resistance.
This type of fin is generally used in situations where the flow resistance requirement is small and its own heat transfer coefficient is relatively large (such as liquid side and phase change).
2.2: Offset fin
Sawtooth fins can be regarded as discontinuous fins formed by cutting straight fins into many short segments and staggering them at a certain interval.
This type of fin is very effective in promoting fluid turbulence and destroying thermal resistance boundary layers. It is a high-performance fin, but the flow resistance is also increased accordingly.
Sawtooth fins are mostly used in situations where heat exchange needs to be enhanced (especially on the gas side and oil side).
2.3: Perforated fin
The porous fin is formed by punching holes in the aluminum foil and then stamping it.
The densely distributed small holes on the fins continuously break the thermal resistance boundary layer, thereby improving the heat transfer performance. The multi-holes are conducive to the uniform distribution of the fluid, but at the same time, they also reduce the heat transfer area of the fins and reduce the fin strength.
The porous fins are mostly used in guide vanes or phase change applications. Because of their medium heat transfer coefficient and flow resistance, they are also commonly used in intercoolers.
2.4: Wavy fin
Corrugated fins are made by punching aluminum foil into a certain waveform to form a curved flow channel.
By constantly changing the flow direction of the fluid, the turbulence, separation and destruction of the thermal resistance boundary layer of the fluid are promoted, and the effect is equivalent to the breaking of the fin.
The denser the corrugation and the larger the amplitude, the more it can enhance the heat transfer.
From our test data, the heat transfer performance of corrugated fins is equivalent to that of serrated fins. In addition, corrugated fins have another important characteristic: they are not easily blocked by debris, and even if they are blocked, the debris is easy to remove.
2.5: Louvered fin
The shutter blade is a fin cut at a certain distance in the direction of fluid flow to form a shutter shape.
It is also a discontinuous fin, and its heat transfer performance is similar to that of serrated blades and corrugated blades. Its disadvantage is that the cut part is easily blocked by dirt.
The specifications given by the Atlas Oilfree department generally mention that this type of fin should not be used. But this type of fin has an advantage. It can be rolled out at high speed on a fin rolling machine, with high processing efficiency.
It is generally used in mass-produced heat exchangers in the automotive industry.
3: We can customize different types of fins for you according to your needs, including the size of the core!