A bead-like condensation-enhanced heat transfer surface structure with hydrophobic bands

Abstract

The invention relates to a drop condensation enhanced heat exchange surface structure with draining hoses. The drop condensation enhanced heat exchange surface structure comprises heat exchange areas and the draining hoses, and the heat exchange areas and the draining hoses are arranged at intervals so as to keep the drop condensation heat exchange process with condensed liquid drops falling off automatically. In the normal working process, the draining hoses on the heat exchange surface structure are perpendicular to the direction of gravity. The heat exchange surface structure is cooled, the temperature of the heat exchange surface structure is kept to be lower than the saturation temperature corresponding to contact gas pressure, and high temperature gas is subjected to drop condensation in the heat exchange areas. As condensation continues, the condensed liquid drops undergo the processes of nucleation, development and combination to be generated continuously and to grow up. Large liquid drops slip down along the surface under the action of gravity, due to the fact that the shapes of the liquid drops are changed suddenly when the liquid drops pass through the draining hoses, the surface energy of the liquid drop part can be converted into kinetic energy, the liquid drops are made to acquire a heat exchange surface normal velocity and to be disengaged from the heat exchange surface completely under the action of the gravity, and the self-disengaging process of the liquid drops is achieved. The drop condensation enhanced heat exchange surface structure with the draining hoses is simple in structure, reliable in working principle and capable of effectively solving the problem that heat exchange capability is weakened obviously due to the failure of the heat exchange areas.

Description

technical field [0001] The invention belongs to the technical field of heat and mass transfer, in particular to a bead-like condensation-enhanced heat-exchange surface structure with hydrophobic bands. Background technique [0002] Bead condensation and film condensation both belong to the form of phase transfer heat transfer. Its principle is to use the latent heat of vaporization released by high-temperature gas when it encounters a low-temperature heat transfer surface as a heat transfer path, which is more efficient than single-phase heat transfer. The form of condensation is bead or film depending on the specific properties of the heat exchange surface. When the heat exchange surface can be well wetted by the condensed liquid, the condensation will form a liquid film, that is, film condensation occurs; when the heat exchange When the surface is not well wetted by the condensing liquid, the condensation will form many small liquid droplets, which is called bead condensat...

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Problems solved by technology

However, the bead-like condensation state is unstable and difficult to maintain, and the bead-like condensation state is easily transformed into a film-like condensation after a long period of operation, so it cannot be applied in the industrial field

On the other hand, the transformation mechanism has not yet been fully revealed. One of the main difficulties it faces is that the surface properties of the heat exchange surface change after a long period of contact with the liquid. At present, there is no surface material or surface treatment technology that can overcome it. the difficulty

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