Elliptical fin tube is a heat exchange element composed of a base tube elliptical tube and outer fins. Common ones include elliptical rectangular fin tubes, elliptical oval fin tubes, oval circular fin tubes, spiral oval flat tubes, oval H-shaped fin tubes, etc. Elliptical fin tubes are attracting attention due to their superior performance compared to circular fin tubes. Elliptical fin tubes have been widely used in industrial fields such as ethylene and oil refining. Elliptical finned tubes are used in heat exchange equipment as high-efficiency heat exchange elements. The outer flow resistance of the tube is small and the heat exchange efficiency is high, making the heat exchange equipment compact, lightweight, efficient and miniaturized. Although research on them has achieved many results, there is still a lot of research work to be done.
Elliptical Finned Tube
Characteristics of elliptical finned tubes
(1) Compared with round finned tubes, elliptical finned tubes are easier to achieve compact layout, which reduces the overall volume of the entire heat exchanger, thereby reducing the floor space.
(2) Due to the shape characteristics of the elliptical finned tube, the air side resistance is small and the heat transfer coefficient between the fluids increases; the thermal resistance ratio inside the tube is small, which increases the heat transfer amount of the fluid in the tube.
(3) The heat transfer area of elliptical fin tubes is larger than that of circular tubes with the same cross-sectional area. This is because the heat transfer perimeter of the elliptical tube is longer for the same cross-sectional area.
(4) The most commonly used elliptical fin tubes are rectangular steel fins, which have high strength. The base tube is not suitable for freezing cracking in winter and has a long service life.
(5) Since elliptical finned tubes can be arranged more compactly, the front row tubes have a greater impact on the rear rows. The outer flow resistance of the tubes can be reduced by increasing the fin spacing of the rear row tubes, but the number of tube rows should not be too large.
Key points of elliptical finned tubes:
- Advantages of Elliptical Finned Tubes:
– Elliptical finned tubes offer advantages such as small external resistance, high heat exchange efficiency, and contribute to compact, lightweight, efficient, and miniaturized heat exchange equipment.
– Despite these advantages, there is a scarcity of research on elliptical finned tubes, indicating potential for further investigation.
- Fin Efficiency in Heat Transfer Calculations:
– Fin efficiency is crucial in heat transfer calculations, and various methods exist for calculating the fin efficiency of elliptical fin tubes, mainly based on the equivalent method.
– The notes that there are deviations in the equivalent method, and corrections should be made for more accurate results and practical guidance in projects. The need for more systematic research in this area is emphasized.
- Comprehensive Research on Elliptical Finned Tubes:
– Research on the internal and external characteristics and heat transfer laws of elliptical finned tubes has been comprehensive, with theoretical analysis, experimental research, and numerical simulation conducted by scholars globally.
– However, there is a relative lack of studies on flat tube finned tubes, especially regarding the temperature and velocity fields inside and outside flat tube finned tubes.
– While flat tube finned tubes exhibit low air-side resistance and high heat transfer coefficients, the text points out challenges related to large internal fluid resistance and limited refrigerant charge, restricting their application in heat exchangers.
– Addressing the internal flow resistance of flat tubes requires more in-depth research for potential solutions.
Overall, the artical emphasizes the potential of elliptical finned tubes, identifies areas where further research is needed, and highlights the importance of addressing challenges associated with flat tube finned tubes in heat exchanger applications.