Nano-coating for unsaturated evaporation heat transfer surface

Abstract

The invention discloses a nano-coating for an unsaturated evaporation heat transfer surface. An anti-corrosion layer and a hydrophilic layer can be coated on the heat transfer surface in sequence; a heat transfer layer can be coated between the anti-corrosion layer and the hydrophilic layer; the coated heat transfer surface is irradiated with ultraviolet light for one hour, so that a contact angle between a coated surface and a water film is reduced to 0-5 degrees; the coating thickness of the anti-corrosive layer is 2-15 nanometers; the coating thickness of the hydrophilic layer is 8-35 nanometers; and ultraviolet light is used for irradiating intermittently every 2-3 days, so that the hydrophilicity of the coated surface is kept. The material characteristic of a heat exchange surface is improved, so that a spreading area on the heat transfer surface under the unit water amount of the water film is increased, distribution is more uniform, the phenomenon of 'dry spot' is avoided effectively, the scaling phenomenon of the heat transfer surface is delayed, heat and mass transfer coefficients between water and air are increased, and heat exchange performance is enhanced.

Description

technical field [0001] The invention relates to a nano-coating for an unsaturated evaporation heat transfer surface, which belongs to the technical field of enhanced heat transfer. Background technique [0002] With the increasingly prominent energy and environmental issues, the issue of energy saving and water saving has attracted widespread attention. As a high-efficiency energy-saving water-saving heat exchange equipment, evaporative condensers have been widely used in our country. [0003] In the working process of the evaporative condenser, the unsaturated evaporation of the heat exchange surface involves the heat and mass transfer of the air-water two-phase flow. A layer of water film is formed on the surface of the heat pipe, and the air is blown in from the bottom of the tube bundle to exchange heat and mass with the water film on the surface of the tube to form unsaturated evaporation, in which the flow and distribution characteristics of the water film on the heat ...

AI Technical Summary

Problems solved by technology

Unsaturated evaporation mainly occurs at the contact interface between the water film on the surface of the heat transfer tube wall and the air. This process is a discontinuous falling film process. It is difficult for the water film to cover the surface of the tube uniformly, so the maximum unsaturated evaporation cannot be achieved; Where the water film cannot cover, due to the existence of evaporation, it is easy to form a "dry spot" phenomenon. After a long time, not only the formation of scale will greatly reduce the heat transfer efficiency, but also cause corrosion damage to the pipe wall

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