A surface treatment method for improving heat transfer coefficient of heat exchanger

Abstract

The invention relates to a surface treatment method capable of increasing the heat exchange coefficient of a heat exchanger, and belongs to the technical field of heat exchangers. The surface treatment method comprises the steps that copper salt is added into water to be prepared into a copper salt solution, and silver salt is added into water to be prepared into a silver salt solution; acid is added into the copper salt solution to obtain a copper salt-acid surface treatment solution, and acid is added into the silver salt solution to be prepared into silver salt-acid surface treatment solution; under the condition of the temperature of 20-90 DEG C, the heat exchanger is placed into the copper salt-acid surface treatment solution or the silver salt-acid surface treatment solution to be treated for 0.5-8 h, and then the heat exchanger porous surface is obtained; or an acid solution is prepared, under the condition of the temperature of 20-90 DEG C, the heat exchanger is placed into thecopper salt solution or the silver salt solution to be soaked and react for 0.1-30 s and then placed into the acid solution with the temperature of 20-90 DEG C to be soaked and react for 0.5-8 h, andthen the heat exchanger porous surface is obtained. According to the surface treatment method, the heat exchange coefficient of the heat exchanger can be effectively increased through a replacement reaction, and boiling heat transfer of a working medium is enhanced.

Description

technical field [0001] The invention relates to a surface treatment method for improving the heat transfer coefficient of a heat exchanger, belonging to the technical field of heat exchangers. Background technique [0002] The most important progress in heat transfer enhancement technology is brought about by changing the morphology to bring about high-performance nucleate boiling. Compared with its single-phase forced convection, the heat transfer coefficient of boiling heat transfer of liquid working medium is 1~2 orders of magnitude higher. Since the 1960s, commercial enhanced heat transfer surfaces have gradually appeared. According to the strengthening principle, it is mainly divided into three categories: surface coating, coating and overall roughening method. Among these methods, the microstructured surface has the most significant heat transfer ability and the highest economic benefit, so it has attracted the most attention. [0003] For the surface covering metho...

AI Technical Summary

Problems solved by technology

The biggest disadvantage of this method is that the production process is too complicated

The micro-porous and micro-grooved structures produced by machining have high thermal conductivity and can withstand high heat flux density, but their production is labor-intensive, and the pores formed are often large, which means that on the one hand, they can provide capillary Too little pressure, on the one hand, the strengthening effect on highly wettable organic matter is reduced

In addition, its porosity is low, about 30~35%

Although the heat transfer performance of flame or plasma sprayed microstructure is high, it is difficult to precisely control the structural parameters, and it is impossible to create a metal porous layer on the inner surface of the tube.

In addition, because the processing process is accompanied by high temperature, the pores are easy to shrink and the particles are easy to melt, so the porosity is low (30~45%)

The heat transfer performance of the microporous surface made by the sintering process is very good, and it has the best heat transfer enhancement performance currently recognized. In addition, it is easy to produce and can be sintered on the inner and outer surfaces of metal pipes, but its cost is high

The current method of using chemical corrosion to obtain the porous surface structure of the heat exchanger has the following problems: (1) because the porous layer obtained by this method has a small pore size and uneven distribution; (2) because the strength of the material decreases and the service life is short; (3) The processing technology is complicated and the cost is high

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