Porous hydrophilic stainless steel heat exchange tube and surface treatment method thereof

Abstract

The invention discloses a surface treatment method for a porous hydrophilic stainless steel heat exchange tube. The method includes the following steps that liquid phase plasma electrolysis or laser polishing or sand blasting treatment is carried out on a stainless steel tube to achieve surface roughening; chemical electrolysis or sol modified electroplating treatment is conducted on the roughened steel tube surface; a stainless steel heat exchange tube and a heat exchanger with the stainless steel heat exchange tube are obtained through the steps. According to the method, porous and recess microstructures can be obtained from surfaces of various stainless steel tubes, and reinforcement evaporation and boiling heat transfer are greatly improved; continuous strong hydrophilic performance can be obtained from the surfaces of various stainless steel tubes, water film spreading is accelerated, the thickness of a water film can be reduced, and therefore heat exchange efficiency is improved; metal surfaces more resistant to pitting corrosion, chloridion stress corrosion and concentration difference micro cell corrosion can be obtained from the surfaces of various stainless steel tubes, overall stability of a heat exchanger unit is improved, and the service life of the heat exchanger unit is prolonged.

Description

technical field [0001] The invention relates to the technical field of heat transfer equipment, in particular to a porous hydrophilic stainless steel heat exchange tube for enhancing evaporation heat transfer outside the tube and a surface treatment method thereof. Background technique [0002] At present, falling film heat exchangers are widely used in the evaporators and absorbers of absorption refrigerators and heat pumps. Their shells operate under vacuum conditions, and the refrigerant is sprayed to the horizontally arranged heat transfer tubes in a certain way. Above, the refrigerant inside the tube is cooled or heated, and the refrigerant outside the tube and the refrigerant inside the tube are used for heat exchange. In order to improve the heat exchange efficiency, strengthen the evaporation outside the tube and reduce the volume of the heat exchange equipment, it can be achieved by changing the shape or surface morphology of the heat exchange tube. The former uses...

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Problems solved by technology

The main problems in the machining method include: (1) The ductility, elastic modulus, hardness, etc. of the pipes make it impossible for ferritic stainless steel, duplex steel, martensitic stainless steel pipes and other pipes to achieve surface porosity through machining; ( 2) Structures such as internal and external teeth and internal and external threads have higher requirements for wall thickness, which increases the weight of the pipe; (3) The fin shape and gap are easy to form refrigerant stagnation areas, which increase the resistance of condensate film formation, and are more sensitive to refrigerants with high viscosity. It is easy to form a dead zone that is not "wetted" and reduce the heat transfer efficiency; (4) High-efficiency carbon steel pipes and stainless steel pipes produced by machining are prone to pitting corrosion during service because they have not undergone surface treatment. It will also accelerate the development of corrosion and reduce the service life of heat exchange tubes

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