Regarding the Advantages and Disadvantages of Helical Finned Tubes and H-shaped Finned Tubes
1. Accumulation of Ash and Wear:
- Research conducted both domestically and internationally indicates that H-shaped finned tubes exhibit superior anti-ash accumulation and wear resistance performance compared to helical finned tubes.
2. Helical Finned Tubes and H-shaped Finned Tubes Heat Transfer Performance:
- The fusion rate of fins with steel tubes in H-shaped finned tubes exceeds 95%, resulting in low contact thermal resistance and excellent heat conduction.
- Although helical finned tubes have fewer air flow disturbances, they experience a certain reduction in external heat exchange. However, due to the near-counterflow characteristics of air flow between heat transfer tube bundles during operation, ash accumulation on the heat exchange surface is minimal, and fins receive more uniform cleaning. H-shaped fins have a higher effective utilization rate of extended surface area compared to helical finned tube bundles, leading to an approximate 10% increase in overall heat transfer efficiency.
3. Helical Finned Tubes and H-shaped Finned Tubes Manufacturing Costs:
- H-shaped finned tubes have a high surface area extension rate, low ash accumulation, and high heat transfer efficiency.
- Under equivalent heat transfer capacity conditions, heat exchangers with H-shaped finned tubes occupy minimal space, allowing for a reduction in the use of high-grade materials (pressure tubes) and increased utilization of low-grade materials (fins). For new engineering projects, this can reduce the height of heat exchanger installations, significantly reduce overall weight, lower the load on suspension systems, and decrease overall costs. In retrofit projects, it is possible to arrange as much heat exchange surface area as possible within limited space, reduce exhaust gas temperatures, improve waste heat recovery efficiency, or facilitate maintenance by increasing access space.
4. Self-Cleaning Function:
- H-shaped fins have a gap in the middle ranging from 6 to 15mm, which guides airflow to blow away accumulated ash on the tube fins. Under suitable wind speeds, this provides effective self-cleaning capability.
- Helical finned tubes tend to accumulate ash more severely due to the spiral angle of the fins. They should be avoided in situations where loose ash accumulation cannot be achieved. Practical operating experience shows that H-shaped finned tubes do not accumulate ash or accumulate very little, while helical finned tubes suffer from significant ash accumulation.
5. Reduction of Smoke Side Resistance:
- H-shaped finned tubes have straight channels on both sides, while the spiral angle of helical fins guides airflow to change direction, making helical finned tubes prone to ash accumulation and resulting in higher smoke side resistance compared to H-shaped finned tubes. Therefore, using H-shaped finned tubes can reduce air resistance, lower the operational and investment costs of induced draft fans.
6. Current Application Status of H-shaped Finned Tubes in Low-Temperature Economizers:
- Increasingly, power plants are choosing H-shaped finned tubes when selecting the heat exchange tube form for low-temperature economizers. - Our company has completed over 30 projects in the past two years, all of which have utilized H-shaped finned tubes. In recent tendered projects, almost all of them have required the use of H-shaped finned tubes. This indicates that H-shaped finned tube heat exchangers have become the mainstream product in the application of low-temperature economizers.
H-shaped Finned Tubes |
