Introduction to Fins of Plate-Fin Heat Exchangers

Fins are the most fundamental components of plate-fin heat exchangers, primarily responsible for heat transfer. Fins are mainly manufactured using two methods: stamping or rolling. In production, fins with lower height and larger pitch are generally formed by rolling (using a fin rolling machine), while fins with higher height and smaller pitch are typically produced by stamping (using a corrugating machine). Stamping has lower production efficiency, whereas rolling offers higher production efficiency. Commonly used aluminum foil thicknesses are 0.15mm, 0.17mm, and 0.2mm. The height of fins can be adjusted according to requirements, but the pitch is fixed.

Fins come in various structural types, such as serrated, plain, and perforated, allowing for the selection of the most suitable fin type based on different operating conditions. The extended surface area of the fins and their ability to disturb fluid flow determine the heat exchange capacity.

These fins consist of long, smooth-walled rectangular channels. Their heat transfer and flow characteristics resemble fluid flow in long circular pipes. As shown in Figure 1.

Figure 1: Plain Fin

The fluid flow channels are embossed with irregularities to increase turbulence, thereby enhancing the heat transfer process. These are known as "high-efficiency fins." See Figure 2.

Figure 2: Serrated Fin

These are plain fins pressed into specific corrugations to promote fluid turbulence. The denser and larger the corrugations, the better the heat transfer performance.

Figure 3: Corrugated Fin

Figure 4: Perforated Fin