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47 results about "Dropwise condensation" patented technology

In dropwise condensation the condensate liquid collects in the form of countless droplets of varying diameters on the condensing surface, instead of forming a continuous film, and does not wet the solid cooling surface. The droplets develop at points of surface imperfections (pit, scratch), called nucleation sites, and grow in size as more vapour condenses on its exposed surface. When the size of droplets is large there comes a time the droplet breakaway from the surface and knock off other droplets and carries it downstream. The moving droplet devours the droplets of smaller size. Dropwise condensation is one of the most effective mechanism of heat transfer and extremely large heat transfer coefficients can be achieved with this mechanism. In dropwise condensation, there is no liquid film to resist heat transfer, and as a result heat transfer coefficients can be achieved more than 10 times larger than those associated with film condensation, although 3-5 times is more common. Heat transfer coefficients are large so designers can achieve a specified heat transfer rate with a smaller surface area and thus a smaller and less expensive condenser.

Transparent super-hydrophobic nano-array and preparation method thereof

The invention discloses a transparent super-hydrophobic nano-array and a preparation method thereof. The preparation method comprises the following steps: firstly coating the surface of a substrate with zinc oxide seed crystal sol by virtue of a spin coating method or a spray coating method, so as to obtain a uniform nano-seed crystal layer; then controlling the hanging altitude and the position in a low-concentration growth solution prepared from KOH and Zn(NO3)2 by virtue of a vertical cotton thread hanging technique, so as to obtain a transparent zinc oxide nano-array, and carrying out fluorination to construct excellent super-hydrophobicity; and carrying out double-surface coating, sintering and growth on the substrate, so as to obtain the transparent super-hydrophobic nano-array on two surfaces of the substrate. Liquid drops with condensed and frosted surfaces are of a sphere shape, small in sizes, extremely easy to combine and bounce, high in desorption rate and low in coverage rate, present excellent frosting resistance and have important application prospects in products of building exterior glass, solar cells, automotive glass and the like, and furthermore, concepts can be provided for application of dropwise condensation, frosting resisting, freezing resisting and the like.
Owner:SOUTHEAST UNIV

Hydrophobic surface, preparation method and application thereof in dropwise condensation heat transfer

InactiveCN103359684AAccelerated mergerAccelerated sheddingMaterial nanotechnologyIndividual molecule manipulationMicro nanoLevel structure
The invention discloses a hydrophobic surface, a preparation method and application thereof in dropwise condensation heat transfer, and relates to the fields of micro-nano manufacturing, condensation heat transfer and the like. The hydrophobic surface has a micro-nano two-level structure, wherein the micro-nano two-level structure is anisotropic and the hydrophobic surface has anisotropic wettability. On one hand, the micro-nano two-level structure of the hydrophobic surface can promote realization of dropwise condensation, and can significantly improve the heat transfer efficiency compared with the common filmwise condensation,; on the other hand, the anisotropic wettability of the hydrophobic surface can affect condensation and fall of water drops to a certain extent and can accelerate discharge of liquid drops under the influence of gravity and other factors, thereby further improving the condensation heat transfer efficiency.
Owner:XI AN JIAOTONG UNIV

Improved high-efficiency unidirectional heat transfer pipe used for heat dissipation of microelectronics

The invention provides an improved high-efficiency unidirectional heat transfer pipe used for heat dissipation of microelectronics, belonging to the technical field of heat pipes, relating to a strictly unidirectional conductive gravity assisted heat pipe. The heat pipe of the invention is a seal chamber applied to the top of an heat dissipation object and is composed of a condensation section at the upper part, a heat insulation section at the middle part and an evaporation section at the lower part, the interior of the heat pipe is filled with a working medium, and the heat pipe is characterized in that the bottom of the chamber is matched with the shape of the top of the heat dissipation object, and the inner surface is distributed with scratch shallow slots; the top of the chamber is subject to superhydrophobic surface treatment; the inner wall of the chamber is provided with vertically arranged groove channels and capillary column channels separated with rib channels and is subject to superhydrophobic surface treatment; gasification is easier to realize on the surface of the scratch shallow slots at the bottom; the capillary column channels make condensation working medium fluid rapidly reflux, thus avoiding that the working medium of the heat pipe is dried up; and the top of the condensation section is subject to superhydrophobic surface treatment, thus realizing dropwise condensation. Thus, the invention improves condensation heat exchange coefficient and enables the heat pipe to operate normally and stably.
Owner:BEIJING UNIV OF TECH

Novel aluminum material with microscale self-driven dropwise condensation function and preparation method thereof

The invention discloses a novel aluminum material with a microscale self-driven dropwise condensation function and a preparation method thereof. A plurality of nanopores are distributed on the surface of the novel aluminum material; nano protuberance structures are distributed on the tops of the nanopores; and the pores at the nano protuberances are communicated with one another. The preparation method comprises the following steps: placing a cathode and an anode mainly formed by the aluminum material in an electrolyte, thereby forming an oxidation system; applying a scheduled dynamic oxidation process between the cathode and the anode, thereby dynamically regulating the formation and the corrosion degrees of alumina pore walls on the surface of the aluminum material according to the changes of the time, the voltage and the current, i.e., realizing the formation of pore channels and the local over-corrosion of the pore walls on the top of the pores by one step, thus forming composite array structures with nano protuberances on the top of the nanopores. The composite array structures have the excellent the microscale self-driven dropwise condensation function after being decorated by chemical substances with the low surface energy. The preparation method is simple in process and short in period, and is favorable for large-scale production.
Owner:SUZHOU INST OF NANO TECH & NANO BIONICS CHINESE ACEDEMY OF SCI

Method and device for controlling heat transfer performance of droplet condensation on superhydrophobic surface

The invention discloses a control method and device for a condensation heat-transferring property of a super-hydrophobic surface. The control method is characterized by comprising the following steps: modifying the surface of a condensation heat exchanger into a super-hydrophobic surface with a micro structure; utilizing a device which comprises a computer, a control module and a realizing moduleto firstly realize dropwise condensation; and applying mechanical bandwidth micro-vibration to the main body of the condensation heat exchanger so as to compel a condensate water drop in a certain size or within a certain size scope to quickly drop from the surface of the condensation heat exchanger, thereby achieving the purpose of controlling the dropwise condensation heat-transferring property. The control method has the beneficial effects that the condensation heat transfer can be strengthened while the strength of heat exchange property is controlled. By applying micro-vibration to a heat exchange surface, the wetting state of the condensate water drop is changed and the condensate water drop can easily drop from the heat exchange surface; and simultaneously, the applied mechanical vibration is wide-frequency vibration which acts on condensate water drops in different sizes. The control on the dropwise condensation heat-transferring strength is realized by controlling a dropping diameter in a dropwise condensation process.
Owner:UNIV OF SHANGHAI FOR SCI & TECH

Hydrophobic surface dropwise condensation capillary force pickup and vibration control micro-object operation device and method

The invention discloses a hydrophobic surface dropwise condensation capillary force pickup and vibration control micro-object operation device and method and relates to a micron-order object operation and micro-assembling technology. The problems that in the prior art, according to a capillary force operation mode, liquid drops remaining at the tail end after a probe is used for dipping are used as operation conditions, the size of the operation liquid drops cannot be controlled effectively, liquid drops which are too large or too small can cause operation task failure, dynamic control over the operation liquid drops after pickup cannot be achieved, and due to the leading role of adhesive force, micro objects adhere to the tail end of the probe after liquid drop disappearing and cannot fall off smoothly are solved. The device comprises a displacement control mechanism, a cooling working operation mechanism and four connecting studs. The displacement control mechanism comprises a vibration isolation table, a three-axis precision electric displacement platform, a connecting bottom plate, a manual displacement lifting table, a vibration module connecting plate, a micrometer head, a micrometer clamp, a piezoelectric ceramic vibration module and a probe clamp. The device and method are used for the field of micron-order object operation.
Owner:HARBIN INST OF TECH

Method for reducing carbendazim impurity DAP in production process of carbendazim

The invention provides a method for reducing a carbendazim impurity DAP in the production process of carbendazim. The method includes: synthesizing o-phenylenediamie; synthesizing cyanamide based methyl formate; synthesizing carbendazim, namely transferring o-phenylenediamie and cyanamide based methyl formate into a reaction kettle for complexation, dropwise adding hydrochloric acid during complexation, adding an additive into the reaction kettle after dropwise condensation adding of hydrochloric acid is finished, starting a reaction kettle stirring device for sufficient stirring, maintaining temperature, filtering, using water for washing, swabbing-off and drying. The additive is added after condensation is finished on the basis of controlling DAP content, the DAP content can reach level A+ after material drying, the DAP content reaches about 0.5ppm after testing and rectification, DAP does not rebound after overnight placement, production requirements can be met better, and content of the impurity in the carbendazim is lowered. Consequently, through testing, the DAP content of carbendazim raw materials is lowered to be about 0.2ppm, so that quality is improved, carbendazim content is improved from 95% to 96.3%, and DAP+HAP is smaller than or equal to 1.5mg/kg.
Owner:ANHUI DONGZHI GUANGXIN AGROCHEMICAL CO LTD

Heat-exchange intensification apparatus and method for indirect medium heating furnace

The invention relates to an indirect medium heating furnace heat exchange intensifying device and a method thereof. The device comprises a fuel gas decoupling chamber, an air decoupling chamber, a starting sweeping blower, a thermal acoustic coupling pulsating inflamer, a pressure gauge or a vacuum meter, an exhaust device free from condensing gas, a rigid connecting piece, a coil pipe, a shell and an exhaust smoke pipe, wherein, the thermal acoustic coupling pulsating inflamer is composed of an air check valve, a fuel gas check valve, a fuel gas nozzle, a combustion chamber, a tail pipe and an exhaust decoupling chamber. The method includes: the combustion chamber and a smoke tube adopt a gas pulsation heat exchange mode and eradicates a smoke flow boundary layer in the chamber wall and a smoke tube wall, thus improving heat convection coefficient at the smoke gas side and reducing heat exchange area; the heat exchange between the indirect heat transmission medium (water) and the heated fluid coil plate adopts a stable dropwise condensation heat exchange way realized by mechanical vibration of the pipe coil, thus improving heat convection coefficient of the indirect heat transmission medium (water) and the heated fluid coil plate and reducing heat exchange area.
Owner:BEIHANG UNIV

Thermoelectric conversion energy acquisition device based on drop condensation and preparation method

ActiveCN105071698AAvoid condensationRealize collision power generationKinetic-electric generatorElectricityLiquid water
The invention provides a thermoelectric conversion energy acquisition device based on drop condensation and a preparation method. The thermoelectric conversion energy acquisition device comprises a cooling end, an upper polar plate, a lower polar plate, a heat transfer plate and a superhydrophobic wall surface, wherein the heat transfer plate is a metal polar plate with a super strong heat conduction ability, and the lower surface is connected with an outer waste heat source for transferring outer heat energy to liquid water on the upper surface of the heat transfer plate; the side wall and the top layer inner surface of the energy acquisition device adopt superhydrophobic material, water vapors evaporated on the heat transfer plate can be prevented from being condensed on the inner wall, the water vapors are concentrated to be evaporated on the upper polar plate of the top layer inner surface, and dielectric layers of the upper polar plate and the lower polar plate are placed in a vertical opposite mode. When drops condensed on the upper polar plate fall on the surfaces of the dielectric layers, charges on the interface where the drops and the dielectric layers are contacted are redistributed, an instantaneous potential difference between two ends of the inner electrode and the outer electrode is generated, and due to the potential difference, drop collision for power generation is realized, and external heat energy is converted into electric energy.
Owner:SHANGHAI INST OF MICROSYSTEM & INFORMATION TECH CHINESE ACAD OF SCI

Aeolotropic super-hydrophobic surface of aluminum material and preparation method of aeolotropic super-hydrophobic surface

The invention relates to a preparation technology for an aeolotropic super-hydrophobic surface of an aluminum material. According to the preparation technology, directional coarse grinding and directional fine grinding are conducted on the aluminum material successively through a scouring pad, abrasive paper, a steel brush and other hard rough materials; after being put to lye, the aluminum material is descaled, activated, and further roughened; and a multilevel micro-nano composite structure can be constructed through subsequent weak alkaline boiling water soaking treatment, and after the multilevel micro-nano composite structure is subjected to fluoroalkylsilane chemical modification, the aeolotropic super-hydrophobic surface can be obtained. In the direction of directional grinding, an aluminum sheet has the super-hydrophobicity, the contacting angle is larger than 150 degrees, the rolling angle is smaller than 10 degrees, and the contact is in a Cassie compound state; in the direction perpendicular to the grinding direction, the contacting angle is invariant, but the rolling angle is among 10-20 degrees, so that a water drop moves more easily in the parallel direction of a stripe/groove formed during grinding. The aeolotropic super-hydrophobic surface has wide application prospects in the fields of directional condensation water collecting, dropwise condensation heat transferring and directional defrosting deicing as well as microfluid, biomedical equipment and the like.
Owner:SOUTHEAST UNIV

Hydrophilic-hydrophobic heterogeneous patterned surface for enhancing dropwise condensation and preparation method

InactiveCN112588540AOrderly regulation of merge frequencyOrderly regulation of shedding diameterPretreated surfacesCoatingsSuperhydrophobeCondensation heat transfer
The invention discloses a hydrophilic-hydrophobic heterogeneous patterned surface for enhancing dropwise condensation and a preparation method. The preparation method comprises the steps of sequentially polishing and degreasing the surface of a copper substrate to obtain a complete and clean copper surface; etching the copper surface by adopting a chemical etching method to obtain a super hydrophilic surface; coating the super hydrophilic surface with negative photoresist in a spinning manner; irradiating a pattern mask plate under UV light; arranging squares in array in super hydrophilic areas in the pattern mask plate, specifically, the distance between any two adjacent super hydrophilic areas is consistent; developing the copper surface by using a negative photoresist developer; rotationally plating a fluorinated polymer Cytop on the developed copper surface, and forming a superhydrophobic surface on the portion, uncovered by the photoresist, on the copper surface; and heating and curing the copper substrate by adopting a stripping process to obtain the super-hydrophilic/super-hydrophobic patterned combined surface. The hydrophilic-hydrophobic heterogeneous patterned surface prepared by the preparation method can enhance the dropwise condensation efficiency and improve the condensation heat transfer coefficient of the surface.
Owner:JIANGSU UNIV

Metal surface with efficient dropwise condensation function and preparation method thereof

The invention belongs to the technical field of metal surface processing, and discloses a metal surface with an efficient dropwise condensation function and a preparation method thereof. The metal surface comprises a hydrophilic area and a super-hydrophobic area. The method comprises the steps that firstly, a pulse laser is adopted for ablating a metal base material, and a periodicity concave-convex micro-nano structure is prepared on the metal surface; after the surface is cleaned, a low-surface-energy substance is used for modifying the concave-convex micro-nano structure to obtain the super-hydrophobic metal surface; then, through surface precise polish-grinding or pulse laser ablation, the low-surface-energy substance of a protrusion part in the periodicity concave-convex micro-nano structure of the super-hydrophobic surface metal is removed to prepare the metal surface; the hydrophilic area is formed on the surface of the protrusion part without the low-surface-energy substance, and a recessed part coated with the low-surface-energy substance is the super-hydrophobic area. When the metal surface is coagulated, condensation droplets are formed on the hydrophilic area preferentially, since the droplets are limited by the surrounding super-hydrophobic area, the droplets more easily leave from the metal surface, so that the surface always keeps the dropwise condensation state,and the condensation efficiency is improved.
Owner:GUANGDONG UNIV OF TECH

Portable dew collecting device with conical reinforced condensing pipes

The invention provides a portable dew collecting device with conical reinforced condensing pipes, and belongs to the technical field of condensing phase transformation. The portable dew collecting device with the conical reinforced condensing pipes structurally comprises the conical reinforced condensing pipes, condensing pipe hanging racks, a support frame and a dew collecting tank, wherein microgrooves are formed in the outer surfaces of the condensing pipes in the axis direction and are used for downwards discharging condensate; sub-millimeter micro-bulging coarse structures are arranged on rib walls between the micro grooves; hydrophobic modification and hydrophilic modification are respectively carried out on the upper parts and lower ends of the condensing pipes so as to facilitatethe generation of dropwise condensation on the surfaces of the condensing pipes, intensity the condensation process, facilitate the formation of downward capillary differential pressure in the water discharging grooves and promote the discharge of condensed water from the surfaces of the condensed pipes; the condensing pipes are arranged in a staggering manner to increase the windward area; and the condensing pipe hanging racks are connected to the support in a bayonet type, thereby facilitating the disassembly and improving the portability. The whole device has novel structure, good portability, clear principle of water vapor collection and high reliability, can effectively intensify the condensation process of water vapor in the air on the surfaces of the condensing pipes and improves the collection efficiency of the condensed water.
Owner:YANGZHOU UNIV

Control method and device for dropwise condensation heat-transferring property of super-hydrophobic surface

The invention discloses a control method and device for a condensation heat-transferring property of a super-hydrophobic surface. The control method is characterized by comprising the following steps: modifying the surface of a condensation heat exchanger into a super-hydrophobic surface with a micro structure; utilizing a device which comprises a computer, a control module and a realizing moduleto firstly realize dropwise condensation; and applying mechanical bandwidth micro-vibration to the main body of the condensation heat exchanger so as to compel a condensate water drop in a certain size or within a certain size scope to quickly drop from the surface of the condensation heat exchanger, thereby achieving the purpose of controlling the dropwise condensation heat-transferring property. The control method has the beneficial effects that the condensation heat transfer can be strengthened while the strength of heat exchange property is controlled. By applying micro-vibration to a heat exchange surface, the wetting state of the condensate water drop is changed and the condensate water drop can easily drop from the heat exchange surface; and simultaneously, the applied mechanical vibration is wide-frequency vibration which acts on condensate water drops in different sizes. The control on the dropwise condensation heat-transferring strength is realized by controlling a dropping diameter in a dropwise condensation process.
Owner:UNIV OF SHANGHAI FOR SCI & TECH

Dehumidifying method

A dehumidifying method capable of increasing a dehumidification amount by lowering the lowest dew point temperature of a device to near 0 C, comprising the steps of disposing a preheat condenser, an evaporator, and a reheat condenser so that a sensible heat factor is less than 0.5, and condensing, dropwise, the moisture in the air on the surface of the evaporator for dehumidification, whereby, since the condensation load of the condenser is lowered and, accordingly, a condensation temperature and an evaporation temperature are lowered, a temperature difference between an air flow and the surface of the evaporator is increased, and the dropwise condensation of the moisture is promoted to increase the dehumidification amount.
Owner:ZHONGSHAN TOPG ECOLOGY TECH

Three-dimensional patterned surface for enhancing dropwise condensation

The invention provides a three-dimensional patterned surface for enhancing dropwise condensation. The three-dimensional patterned surface comprises a super-hydrophobic substrate and an upper convex super-hydrophilic three-dimensional pattern, wherein the upper convex super-hydrophilic three-dimensional pattern comprises a plurality of upper convex super-hydrophilic three-dimensional structures anda droplet collection area, and the upper convex super-hydrophilic three-dimensional structures independently form an array distribution or the ends of the plurality of upper convex super-hydrophilicthree-dimensional structures are connected to form a cluster array distribution; the cross-sectional shape of the parallel surface of each upper convex super-hydrophilic three-dimensional structure iswedge-shaped; the cross-sectional shape of the vertical surface of each upper convex super-hydrophilic three-dimensional structure includes, but is not limited to, rectangular and inverted cones. According to the three-dimensional patterned surface, the transverse growth space of dropwise condensate liquid can be restrained, the size of the dropwise condensate liquid to be separated from a film-shaped area is remarkably reduced, and the transmission and convergence of the condensate liquid in the film-shaped area are promoted; and the cluster-like combination of a three-dimensional pattern can reduce the overall separation resistance of the surface condensate liquid, improve the dropwise condensation efficiency and long-acting property, and have important application value in the aspectsof high-efficiency water collection, condensation heat transfer and manufacturing of novel high-performance heat pipes.
Owner:NANJING UNIV OF AERONAUTICS & ASTRONAUTICS

Wire-tube composite structure used for evaporation and condensation of inner surface

The invention relates to the technical field of evaporative condensers and sea water desalination, and more particularly discloses a wire-tube composite structure used for evaporation and condensationof an inner surface. The wire-tube composite structure used for the evaporation and the condensation of the inner surface comprises a condensing copper tube and tube attachment copper wire bundles; and a plurality of the tube attachment copper wire bundles are arranged and are connected to the condensing copper tube. According to the wire-tube composite structure used for the evaporation and thecondensation of the inner surface, the contact area between the needle-like tube attachment bundle-like copper wires and high-concentration steam is increased greatly, meanwhile, filmwise condensationis difficult to form on the surfaces of tube attachment bundle-like copper wires, heat at a steam generating part is rapidly led out in a dropwise condensation mode, condensation droplets slide downdirectly along the tube attachment bundle-like copper wires and are transferred to the position of low-concentration steam, and the condensing copper tube adopts a copper tube with excellent heat-conducting property which can absorb more heat maximally, so that the tube attachment bundle-like copper wires are cooled quickly in time to promote the generation and the condensation of the steam; materials are low in cost and easily obtained; and a manufacturing process is simple.
Owner:HARBIN INST OF TECH
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