Thermodynamic calculation of boilers is an important part of boiler performance design. The accuracy of thermodynamic calculation, i.e. the quantity of heating surface, is the basis of ensuring the output, parameters, thermal efficiency and cost of waste heat boiler. Different types of spiral finned tubes, such as spiral fins, H-shaped or dish-shaped fins, have been widely used in conventional power plant boilers, circulating fluidized bed boilers and waste heat boilers in metallurgical, chemical and building materials industries. However, in the design process, the standard calculation method imported from abroad or the former Soviet Union is mainly adopted, and the long-term design experience of designers or the simulation test results of finned tube bundles with certain structures are used. At present, there are no mature and standardized calculation methods for finned tube bundles in China.
The same is true for heat transfer calculation of spiral fin tubes in combined cycle waste heat boiler. In the standard calculation method introduced abroad or in the former Soviet Union, although there is a method for calculating the heat transfer and resistance of spiral finned tube bundles, its application is limited. On the one hand, the structural parameters, such as tube spacing, fins specification, etc. On the other hand, it can not fully reflect the influence of gas turbine exhaust pollution characteristics on heat transfer calculation.
In addition, the heat transfer characteristics of spiral finned tube are still related to the welding method and welding rate of finned tube, and the welding process of finned tube at home and abroad is inevitably different. These factors limit the further optimization of finned tube and heating surface structure and layout in the design of finned tube heating surface of combined cycle waste heat boiler and other waste heat boiler and the localization of finned tube bundles. Finned tube affects the performance and cost of waste heat boiler to a certain extent.
In addition, when gas turbine exhaust gas passes through the spiral finned tube to heat the steam in the tube, although the spiral finned tube enhances the heat transfer capability of the heating surface, it also makes the fin outside the tube work in harsh high temperature environment, which makes the temperature of the spiral fin outside the tube often higher, possibly exceeding the allowable temperature limit of the material, resulting in the fin. It was burnt out. For waste heat boilers, the high pressure superheater and reheater heating surfaces have higher flue gas outside the tube and the working medium inside the tube. If the fin height is unreasonable, the temperature of the outer end of the spiral fin, usually called the fin temperature, may exceed the allowable temperature of the fin material, which may cause the fin to burn down and affect the waste heat. Boiler operation reliability. To sum up, it is necessary to study the heat transfer and resistance characteristics of finned tubes and finned tubes with different structures, and the temperature distribution of spiral fins.
标签:   翅片管 环氧地坪 地坪 环氧地坪漆 环氧地坪施工