Views:1 Author:Site Editor Publish Time: 2020-03-12 Origin:Site
1. Heat pipe heat exchangers are divided according to form, including integrated heat pipe heat exchangers, separated heat pipe heat exchangers, rotary heat pipe heat exchangers and volute heat pipe heat exchangers.
(1) Integrated heat pipe heat exchanger
The integrated heat pipe heat exchanger is the most common type of heat pipe heat exchanger. This heat exchanger consists of a branch heat pipe element. The two heat exchange fluids are located at the upper and lower parts of the heat exchanger. The middle is separated by a tube sheet, and the heat pipe is suspended from the tube sheet. The place can adopt a static seal or a welded structure, depending on the design needs.
The movable static sealing structure is adopted to facilitate the maintenance and cleaning of the heat pipe; the welding structure is reliable and sealed, and there is no hidden danger of fluid leakage on both sides.
In order to overcome the problem of low heat transfer coefficient of gas-to-gas heat transfer, the heat transfer area of the outer wall separated by the heat pipe is moderately expanded by using fins. In this way, the heat transfer outside the pipe is fully strengthened. It also effectively reduces the volume and weight of the heat exchanger, saves metal consumables, and can obtain a cost-effective heat exchanger.
Some small gas-liquid heat exchangers, gas-steam heat pipe heat exchangers and waste heat boilers are also often made in one piece. For the replacement of heat pipes with large structure and large pressure of liquid or steam, considering the strength of the shell and the tube sheet, it is often not appropriate to use the integral type. Where conditions permit. Can be designed as a small heat exchanger unit, and then they are connected in series and combined.
(2) Separate heat pipe heat exchanger
Separate heat pipe heat exchanger is a unique structure in the heat exchanger. This heat exchanger is flexible in arrangement and free to change. It can realize long-distance exchange exchange; it can realize the simultaneous heat exchange of one fluid and multiple fluids; it can completely reduce two or more heat exchange fluids. The heating section and the condensing section of the separate heat pipe are in two independent heat exchange fluid channels. The working liquid inside the heat pipe passes the steam after the heat absorption and evaporation, and the riser pipe sends the air stream to the condensation section. After the heat is condensed, it passes the condensation. The liquid downcomer returns to the heating section.
The distance between the heating evaporation section and the exothermic condensation section of the separated heat pipe heat exchanger and the height difference between each other are also related to the pressure loss along the steam flow. In theory. On the other hand, the height difference between the heating evaporation section and the exothermic condensation section is the smallest, and the diameter of the steam rising tube is displaced, and the distance between them can be farther, so as to ensure the normal operation cycle of the heat pipe.
The steam rising pipe and the condensate falling pipe need to implement strict thermal insulation and minimize the displacement loss along the vertical path.
The liquid medium in the pipe with water as the working medium has a higher temperature and steam pressure during operation. When the internal volume and pressure of the pipe row, ascending pipe, and descending pipe reach a certain value, the tube bundle must be designed according to the relevant specifications of the pressure vessel , Manufacturing and inspection.
When making full use of the advantages of a separate heat pipe heat exchanger, we must also pay attention to overcoming some of its disadvantages. For example, making on-site connections is more complicated, filling of working fluids, and forming of the degree of vacuum of the heat exchange tube bundles are difficult. Insulation, thermal expansion and contraction along the connection line can not be ignored.
2. According to the function, the heat pipe heat exchanger can be divided into: gas-gas type, gas-vapor type, gas-liquid type, liquid-liquid type, and liquid-gas type.
3. Commonly used are heat pipe waste heat boilers (also called heat pipe steam generators).
Heat pipe waste heat boiler Heat pipe waste heat boiler is a kind of steam generating equipment with strong practicability, reliable structure and high thermal efficiency.
There are two main types of heat pipe waste heat boilers: integral and split.