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Longitudinal finned tube is a kind of efficient heat exchange element, and its core feature is that the fins are arranged in parallel along the length of the tube (rather than spirally wound). This structural design mainly serves to enhance the heat transfer efficiency. Its technical points and application characteristics are as follows:
1. Core structure and design principle of longitudinal finned tube
Structural features: Longitudinal finned tubes usually use high-frequency welding technology, which uses the skin effect and proximity effect generated by high-frequency current to make the fins and base tubes reach high temperature in a short time and achieve molten welding, ensuring the close combination of the fins and base tubes, thereby improving strength and durability.
Fin direction
The fins extend parallel to the tube axis to form a longitudinal heat dissipation surface, which is different from the rotating layout of spiral finned tubes.
Enhanced heat transfer mechanism
Increase heat exchange area: The fins significantly expand the surface area of the base tube and increase the contact range between the heat medium and the ambient medium.
Optimize fluid dynamics: The longitudinal fins can guide the fluid to flow in a specific direction, reduce eddy resistance, and are suitable for large flow scenarios.
2. Manufacturing process and type of longitudinal finned tube
Manufacturing process: High-frequency welding technology is the key process for manufacturing longitudinal finned tubes. It does not require flux and solder, is simple to manufacture, and has excellent heat transfer and mechanical properties. In addition, galvanizing can enhance the corrosion resistance of finned tubes and extend their service life.
Mainstream manufacturing technology
High-frequency welding: The fins and the base tube are partially melted and bonded by high-frequency current, and the weld is uniform and firm with excellent thermal conductivity.
Wrap-around process: The metal strip is tightly wrapped around the outer wall of the base tube through mechanical force. The cost is low, but the bonding strength is weaker than welding.
Material selection
Common corrosion-resistant materials such as stainless steel and galvanized steel are suitable for harsh environments such as chemical and electric power.
3. Performance advantages of longitudinal finned tubes
Thermal efficiency characteristics
The longitudinal pitch change has little effect on the heat transfer performance, and the design flexibility is high.
Heat is evenly transferred along the length of the tube to avoid local overheating.
Fluid adaptability
The large-diameter design (common in industrial models) can handle high-flow media with low pressure drop loss.
4. Typical application areas of longitudinal finned tubes
| Application Scenario | Function | Case |
|---|---|---|
| Industrial Waste Heat Recovery | Recover High-Temperature Waste Gas Heat Energy | Heat Exchangers in Power and Metallurgical Industries |
| Large Building Heating | Air Heating/Cooling | Finned Radiators |
| Chemical Equipment | Heat Exchange for Corrosive Media | Reactor Auxiliary Heat Exchange System |
5. Comparison with horizontal design
Longitudinal finned tubes can provide lower flow resistance in the same space, but the heat exchange area per unit length is usually smaller than that of spiral finned tubes. Its core advantages are high structural stability (especially welding process) and low maintenance cost, which are suitable for long-term heavy industrial scenarios.
