CN209783328U - Device for strengthening condensation heat exchange - Google Patents
Device for strengthening condensation heat exchange Download PDFInfo
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- CN209783328U CN209783328U CN201920148117.2U CN201920148117U CN209783328U CN 209783328 U CN209783328 U CN 209783328U CN 201920148117 U CN201920148117 U CN 201920148117U CN 209783328 U CN209783328 U CN 209783328U
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Abstract
The device for strengthening condensation heat exchange comprises a hydrophobic substrate, wherein the surface of the hydrophobic substrate is a hydrophobic surface; the hydrophobic substrate is provided with a plurality of hydrophilic artificial nucleation points positioned on the surface of the hydrophobic substrate, and the surfaces of the hydrophilic artificial nucleation points are hydrophilic surfaces; condensate droplet one side is first side position, and the opposite side is the second side position, and the area of hydrophilic artificial nucleation point in the first side position and the ratio of first side position total area are first face integral number, and the area of hydrophilic artificial nucleation point in the second side position and the ratio of second side position total area are second face integral number, and first face integral number is greater than second area fraction. The utility model discloses still relate to the method of reinforceing the condensation heat transfer, including following step, when the energy that the condensation liquid drop obtained from the external world and/or self gathered surpassed the energy that the condensation liquid drop edge broke away from the second side and need overcome, the condensation liquid drop moved to first side displacement by the second side position, promoted the condensation liquid drop and removed, reached the effect that promotes condensation heat transfer process.
Description
Technical Field
the utility model relates to an reinforce condensation heat transfer technical field, concretely relates to reinforce device of condensation heat transfer.
Background
the nucleation of the liquid drops and the discharge of the generated liquid drops in the condensation process are widely existed in the nature, industrial production and scientific research, and have wide application in the fields of energy, chemical engineering, medical treatment, seawater desalination, liquid drop collection, molecular biology and the like. For example, in a condensation apparatus, the droplet-like condensation process mainly includes three processes of droplet generation (nucleation), droplet growth, and droplet detachment. How to promote the nucleation of the liquid drops and the timely separation of the generated liquid drops is a key technical problem to be solved for strengthening the condensation heat exchange process and improving the efficiency of the condensation equipment.
disclosure of Invention
An object of the utility model is to provide a reinforce device of condensation heat transfer, this reinforce device of condensation heat transfer can be effectual the nucleation process of promotion condensation in-process condensation liquid drop, promote the motion that generates the condensation liquid drop simultaneously, make the condensation liquid drop of formation in time discharge to promote condensation heat transfer process. The technical scheme is as follows:
The device for strengthening condensation heat exchange comprises a hydrophobic substrate, wherein the surface of the hydrophobic substrate is a hydrophobic surface;
The hydrophobic substrate is provided with a plurality of hydrophilic artificial nucleation points positioned on the surface of the hydrophobic substrate, and the surface of each hydrophilic artificial nucleation point is a hydrophilic surface;
The condensation liquid drops are converged on the surface of the hydrophobic substrate, the position of one side of the condensation liquid drops in the length direction of the hydrophobic substrate or the position of one side close to the middle of the hydrophobic substrate or the position of one side far away from the middle of the hydrophobic substrate is a first side position, the position of the other side of the condensation liquid drops is a second side position, the ratio of the area of the hydrophilic artificial nucleation points contained in the first side position to the total area of the first side position is a first surface integral number, the ratio of the area of the hydrophilic artificial nucleation points contained in the second side position to the total area of the second side position is a second surface integral number, and the first surface integral number is larger than the second surface integral number.
The hydrophilic artificial nucleation points are respectively arranged in artificial nucleation columns which are parallel to each other and vertical to the movement direction of the condensed liquid drops, and the distribution density of the hydrophilic artificial nucleation points is gradually increased along the direction vertical to the artificial nucleation columns.
The hydrophilic artificial nucleation sites in the same artificial nucleation column are uniformly distributed.
the distribution density of the hydrophilic artificial nucleation points is gradually reduced or increased from the middle part to the periphery.
The surface of the hydrophobic substrate is a wetting gradient surface, and the included angle between the direction of increasing hydrophilicity of the surface of the hydrophobic substrate and the direction of the first side position facing the second side position is larger than 90 degrees.
The surface of the hydrophobic substrate is a super-hydrophobic surface.
Hydrophobic base plate includes basement and arch, the arch sets up the surface of basement, part bellied surface machining is hydrophilic surface, bellied difference in height is within one fifth of self height, just bellied height is 5 microns to 40 microns, between adjacent bellied interval is 10 microns to 100 microns.
The protrusions are cylindrical and have a diameter of 5 to 15 microns.
The distance between the protrusions at the second side position is larger than the distance between the protrusions at the first side position.
The direction from the second side position to the transition between the first side positions is a gradient direction, and the distance difference between the bulges in the gradient direction is the same or gradually reduced and is reduced in an equal difference manner.
the ratio of the number of the projections having the hydrophilic surface contained in the first side position to the total area of the first side position is a first number fraction; the ratio of the number of the projections having the hydrophilic surface contained in the second side position to the area of the second side position is a second number fraction, and the first number fraction is larger than the second number fraction.
the distance between the bulges at the second side position is larger than the distance between the bulges at the first side position.
The height of the projections is 15 to 25 micrometers, and the distance between adjacent projections is 20 to 70 micrometers.
the height of the projections is 20 microns, and the distance between adjacent projections is 20 microns, 25 microns, 30 microns, 35 microns or 40 microns.
The method for strengthening condensation heat exchange comprises the following steps,
the condensed liquid drops nucleate on the surface of the hydrophobic substrate and the hydrophilic artificial nucleation points, the surface of the hydrophilic artificial nucleation points is a hydrophilic surface, the surface of the hydrophobic substrate is a hydrophobic surface, and the condensed liquid drops nucleate on the surface of the hydrophilic artificial nucleation points more easily than on the surface of the hydrophobic substrate;
The position of one side of the condensed liquid drop in the length direction of the hydrophobic substrate or the position of one side close to the middle of the hydrophobic substrate or the position of one side far away from the middle of the hydrophobic substrate is a first side position, the position of the other side of the condensed liquid drop is a second side position, the ratio of the area of the hydrophilic artificial nucleation point contained in the first side position to the total area of the first side position is a first surface integral number, the ratio of the area of the hydrophilic artificial nucleation point contained in the second side position to the total area of the second side position is a second surface integral number, the first surface integral number is larger than the second surface integral number, and when the energy obtained by the condensed liquid drop from the outside and/or the energy accumulated by the condensed liquid drop exceeds the energy required to be overcome when the edge of the condensed liquid drop is separated from the second side position, the condensed liquid drop moves to the first side position from the second side position.
in the step of displacing the condensed liquid droplets from the second side to the first side, further comprising the step of,
The energy required to overcome when the condensed liquid drops are separated from the first side position and the second side position is first movement energy and second movement energy respectively, and the first movement energy is greater than the second movement energy;
The energy obtained by the condensed liquid drops from the outside and/or the energy accumulated by the condensed liquid drops exceeds the second movement energy firstly, so that the condition that the condensed liquid drops are separated from the second side position is achieved;
The condensate droplets move from the second side to the first side.
After the step of moving the condensed liquid droplets from the second side position to the first side position, further comprising the step of,
The condensed liquid drops are still positioned on the surface of the hydrophobic substrate;
The edges of the condensed droplets are located at a new first side and a new second side;
the energy to be overcome for the condensate droplets to separate from the new first side position and the new second side position is a new first movement energy and a new second movement energy respectively, and the new first movement energy is larger than the new second movement energy;
The energy obtained by the condensed liquid drops from the outside and/or the energy accumulated by the condensed liquid drops exceeds the new second movement energy firstly, and the condition that the condensed liquid drops are separated from the new second side position is achieved;
The condensate droplets move from the new second side position to the new first side position.
The method for strengthening condensation heat exchange comprises the following steps,
the condensed liquid drops nucleate on the surfaces of the protrusions and the hydrophilic surfaces of the protrusions, the hydrophilic surfaces of the protrusions are hydrophilic surfaces, the surfaces of the protrusions are hydrophobic surfaces, and the condensed liquid drops nucleate on the hydrophilic surfaces of the protrusions more easily than on the surfaces of the protrusions;
the position of one side of the condensed liquid drop in the length direction of the hydrophobic substrate, the position of one side close to the middle of the hydrophobic substrate or the position of one side far away from the middle of the hydrophobic substrate is a first side position, the position of the other side of the condensed liquid drop is a second side position, the ratio of the number of the bulges with the hydrophilic surfaces in the first side position to the total area of the first side position is a first quantity fraction, the ratio of the number of the bulges with the hydrophilic surfaces in the second side position to the total area of the second side position is a second quantity fraction, the first quantity fraction is larger than the second quantity fraction, and when the energy obtained by the condensed liquid drop from the outside and/or the energy accumulated by the condensed liquid drop exceeds the energy required to overcome when the edge of the condensed liquid drop is separated from the second side position, the condensed liquid drop moves to the first side position from the second side position.
It should be noted that:
The hydrophilic surface is formed by processing the top surface of the protrusion to change the contact angle between the liquid drop and the protrusion, thereby forming a hydrophilic effect.
the foregoing "first, second, and third … …" do not denote any particular quantity or order, but rather are used merely to distinguish one name from another.
The foregoing "perpendicular", "parallel" and "uniformly distributed" may have certain errors.
The advantages or principles of the invention are explained below:
1. the condensation liquid drop is easy to nucleate on the hydrophilic surface during condensation, and hydrophilic artificial nucleation points with high hydrophilicity are arranged on the hydrophobic substrate, so that the nucleation density and speed of the condensation liquid drop on the hydrophobic substrate are improved, and the nucleation process of the condensation liquid drop in the condensation process is promoted. The nucleation density of condensed liquid drops in the condensation process is improved by arranging a plurality of hydrophilic artificial nucleation points.
the condensed droplets are combined with adjacent condensed droplets to form larger condensed droplets in the growth process, and the condensed droplets can obtain enough energy and move on the hydrophobic substrate in the combination process; after the condensed liquid drops are merged and grow, the condensed liquid drops can also obtain enough energy to move on the hydrophobic substrate due to the action of self gravity and/or other external factors (such as vibration and the like). When the condensed liquid drops move, certain energy is needed to overcome the resistance of the hydrophobic substrate and the hydrophilic artificial nucleation points contained in the hydrophobic substrate to the condensed liquid drops, and the first area integral is larger than the second area fraction, so that the resistance generated by the hydrophobic substrate at the first side position and the hydrophilic artificial nucleation points is larger than the resistance generated by the hydrophobic substrate at the second side position and the hydrophilic artificial nucleation points. The energy that its acquisition or accumulation of condensate droplet reached the condensate droplet before breaking away from the energy that first side position needs in growth process, reached earlier and broken away from the energy that second side position needs to make the condensate droplet move from second side position to first side position, promote the removal of condensate droplet, discharge the condensate droplet more easily, make the surface maintain the dribbling condensation state, thereby realize promoting the process of condensation heat exchange.
The realization increases the nucleation density of condensation liquid drop through a plurality of hydrophilic artifical nucleation points, utilizes the inhomogeneous distribution of hydrophilic artifical nucleation point simultaneously, promotes the removal of condensation liquid drop, makes the condensation liquid drop in time discharge, promotes condensation heat transfer process to improve the efficiency of condensation heat transfer.
2. The density of the distribution of the hydrophilic artificial nucleation points is gradually increased along the direction vertical to the artificial nucleation columns, so that the condensed liquid drops can be promoted to move to the position where the distribution of the hydrophilic artificial nucleation points is dense, the movement and the discharge of the condensed liquid drops are promoted, and the condensation heat exchange process is promoted.
3. The hydrophilic artificial nucleation points in the same artificial nucleation column are uniformly distributed, so that the condensed liquid drops can move towards the direction vertical to the artificial nucleation column more stably.
4. The distribution density of the hydrophilic artificial nucleation points is set to be gradually reduced or increased from the middle part to the periphery, so that the artificial nucleation points can adapt to different drainage structures, and the effect of improving the practicability is achieved.
5. When the condensed liquid drops are positioned at the position with lower hydrophilicity, the condensed liquid drops have the tendency of moving to the position with higher hydrophilicity, and then the effect of promoting the condensed liquid drops to move to the hydrophilic area is achieved. The movement and discharge of the condensate liquid can be further promoted by the non-uniform arrangement of the wetting gradient surface and the hydrophilic artificial nucleation points and simultaneously driving the condensate liquid drops to move, and the condensation heat exchange process is promoted.
6. the advantage that the condensate liquid drops have good fluidity and smaller adhesive force on the super-hydrophobic surface is utilized, the discharging speed of the condensate liquid drops is improved, the effect of promoting the motion of the condensate liquid drops is achieved, the motion and the discharge of the condensate liquid drops are promoted, and the condensation heat exchange process is promoted.
7. Because the integral number of the first surface is larger than the integral number of the second surface, the energy which needs to be overcome when the edge of the condensed liquid drop is separated from the first lateral contact surface is larger than the energy which needs to be overcome when the edge of the condensed liquid drop is separated from the second lateral contact surface, so that the energy (including gravitational potential energy) accumulated by the condensed liquid drop in the growth process is continuously increased, the energy which the edge of the condensed liquid drop needs to be overcome when the condensed liquid drop is obtained from the outside and/or the energy accumulated by the condensed liquid drop exceeds the energy which needs to be overcome when the edge of the condensed liquid drop is separated from the second lateral contact surface before the energy which needs to be overcome when the edge of the condensed liquid drop is separated from the first lateral contact surface is exceeded, and the edge of the condensed liquid drop is separated. In the moving process of the condensed liquid drops, the condensed liquid drops are combined with the adjacent condensed liquid drops, so that the movement of the condensed liquid drops is further promoted, the movement and the discharge of the condensed liquid drops are promoted, and the condensation heat exchange process is promoted.
8. the energy acquired by the condensed liquid drops from the outside and/or the energy accumulated by the condensed liquid drops during the growth process is increased, and the second movement energy of the condensed liquid drops away from the second side position is firstly satisfied, so that the condensed liquid drops move from the second side position to the first side position.
9. after the condensed liquid drops move, the condensed liquid drops move from the new second side position to the new first side position until the energy obtained by the condensed liquid drops from the outside and/or the energy accumulated by the condensed liquid drops exceeds the new second movement energy. This process is repeated until the condensed droplets are able to detach from the hydrophobic substrate.
10. on hydrophobic base plate, set up the arch of micro-structure, and bellied height is 5 microns to 40 microns, and bellied interval is 10 microns to 100 microns, and the condensation liquid drop stands on protruding, forms hydrophobic effect of hydrophobic base plate, and be within one fifth of self height through setting up bellied difference in height moreover for bellied height is more even, and characteristics are unanimous basically every time, and through processing into hydrophilic surface at partly bellied surface, so be favorable to condensation liquid drop nucleation more.
11. By providing different spacings between the projections, a wetting gradient is formed, so that drainage of condensed droplets is facilitated.
12. The direction of the transition between second side position to first side position is the gradient direction, and on the gradient direction interval difference between the arch is the same or reduces gradually, and is the arithmetic decrease, so the arch on the basement is inhomogeneous distribution for moist gradient in the gradient direction gradually changes, is favorable to condensing liquid drop's discharge.
13. Uniformly arranging the bulges on the surface of the substrate, and processing the hydrophilic surface to be non-uniform, namely, the ratio of the number of the bulges with the hydrophilic surface contained in the first side position to the total area of the first side position is a first number fraction; the ratio of the number of the projections with the hydrophilic surfaces contained in the second side to the area of the second side is a second number fraction, the first number fraction is larger than the second number fraction, condensed liquid drops can be nucleated through the hydrophilic surfaces of the projections, a wetting gradient can be formed through the non-uniformly arranged projections, and the condensed liquid drops are favorably discharged.
14. with the arch of inhomogeneous setting, the bellied hydrophilic surface of inhomogeneous setting, the artifical nucleation point of hydrophilic of inhomogeneous setting, the three combines to use, the local area that will protruding unit density is big is first side position, and the big region of bellied hydrophilic surface unit density is first side position, and the big region of the artifical nucleation point unit density of hydrophilic is first side position, the great region of three density is corresponding, make the effect strengthen, more do benefit to the nucleation and the discharge of condensate drop.
15. The height of the projections is set to be 15 to 25 micrometers, the hydrophobic effect is better under the height, the bottoms of the condensed liquid drops can be contacted with air through the height of the projections, the hydrophobic effect is facilitated, and in addition, the distance between the adjacent projections is 20 to 70 micrometers, and the hydrophobic effect is better under the range.
Drawings
fig. 1 is a schematic structural diagram of a first embodiment of the present invention;
Fig. 2 is a schematic view of a structure of a convex hydrophilic surface of a hydrophobic substrate according to a first embodiment of the present invention;
fig. 3 is a schematic structural diagram of a second embodiment of the present invention;
Fig. 4 is a schematic structural diagram of a fifth embodiment of the present invention.
Description of reference numerals:
11. A hydrophobic substrate; 111. a substrate; 112. a protrusion; 12. hydrophilic artificial nucleation sites; 13. condensing the droplets; 14. a first side position; 15. and a second side position.
Detailed Description
the following describes embodiments of the present invention in detail.
Example 1:
As shown in FIG. 1, the device for enhancing condensation heat transfer comprises a hydrophobic substrate 11, wherein the surface of the hydrophobic substrate 11 is a hydrophobic surface, and the intrinsic contact angle of the surface of the hydrophobic substrate 11 is greater than 90 deg. In the present embodiment, the intrinsic contact angle of the surface of the hydrophobic substrate 11 is 120 °. The hydrophobic substrate 11 is provided with a plurality of hydrophilic artificial nucleation points 12 located on the surface of the hydrophobic substrate 11, the hydrophilicity of the hydrophilic artificial nucleation points 12 is higher than that of the surface of the hydrophobic substrate 11, the surface of the hydrophilic artificial nucleation points 12 is a hydrophilic surface, the intrinsic contact angle of the hydrophilic artificial nucleation points 12 is less than 90 °, and in this embodiment, the contact angle of the surface of the hydrophilic artificial nucleation points 12 is 60 °. The plurality of hydrophilic artificial nucleation sites 12 are respectively arranged in artificial nucleation columns parallel to each other and perpendicular to the moving direction of the condensed liquid droplets 13, and the distribution density of the hydrophilic artificial nucleation sites 12 is gradually increased along the direction perpendicular to the artificial nucleation columns. The hydrophilic artificial nucleation sites 12 within the same artificial nucleation column are evenly distributed.
The condensed liquid drops 13 are converged on the surface of the hydrophobic substrate 11, the position of one side of the condensed liquid drops 13 in the length direction of the hydrophobic substrate 11 is a first side position 14, the position of the other side of the condensed liquid drops 13 is a second side position 15, the ratio of the area of the hydrophilic artificial nucleation points 12 contained in the first side position 14 to the total area of the first side position 14 is a first surface integral number, the ratio of the area of the hydrophilic artificial nucleation points 12 contained in the second side position 15 to the total area of the second side position 15 is a second surface integral number, and the first surface integral number is larger than the second surface integral number.
In addition, as shown in fig. 2, the hydrophobic substrate 11 includes a base 111 and protrusions 112, the protrusions 112 are disposed on the surface of the base 111, a part of the surface of the protrusions 112 is processed into a hydrophilic surface, the height difference of the protrusions 112 is within one fifth of the height of the protrusions, the height of the protrusions 112 is 5 micrometers to 40 micrometers, the distance between adjacent protrusions 112 is 10 micrometers to 100 micrometers, the protrusions 112 are cylindrical, the diameter of the protrusions 112 is 5 micrometers to 15 micrometers, and in this embodiment, the distances between adjacent protrusions 112 are the same.
as shown in fig. 2, the ratio of the number of projections 112 with hydrophilic surface contained in first side 14 to the total area of first side 14 is a first number fraction; the ratio of the number of the projections 112 having the hydrophilic surface contained in the second side 15 to the area of the second side 15 is a second number fraction, and the first number fraction is larger than the second number fraction.
Preferably, the height of the protrusions 112 is 15 micrometers to 25 micrometers, and the distance between adjacent protrusions 112 is 20 micrometers to 70 micrometers.
note that the wetting gradient formed by the hydrophilic artificial nucleation sites 12 provided on the surface of the hydrophobic substrate 11 is in a parallel relationship with the pitch of the projections 112 of the hydrophobic substrate 11 itself and the wetting gradient formed by the hydrophilic surface processed on the surface thereof.
The method for strengthening condensation heat exchange of the condensation heat exchange strengthening device comprises the following steps of;
1. The condensed liquid drops 13 nucleate on the surface of the hydrophobic substrate 11 and the hydrophilic artificial nucleation points 12, the surfaces of the hydrophilic artificial nucleation points 12 are hydrophilic surfaces, the surface of the hydrophobic substrate 11 is a hydrophobic surface, and the condensed liquid drops 13 nucleate more easily on the surfaces of the hydrophilic artificial nucleation points 12 than on the surfaces of the hydrophobic substrate 11; the nucleation droplets on the hydrophilic artificial nucleation sites 12 grow continuously and merge with the droplets on the adjacent hydrophilic artificial nucleation sites 12 to grow into slightly larger condensed droplets 13.
2. One side of the condensed liquid droplet 13 in the direction parallel to the surface of the hydrophobic substrate 11 is located at a first side position 14, the other side of the condensed liquid droplet 13 is located at a second side position 15, the ratio of the area of the hydrophilic artificial nucleation point 12 contained in the first side position 14 to the total area of the first side position 14 is a first surface integral number, the ratio of the area of the hydrophilic artificial nucleation point 12 contained in the second side position 15 to the total area of the second side position 15 is a second surface integral number, the first surface integral number is greater than the second surface integral number, and when the energy obtained by the condensed liquid droplet 13 from the outside and/or the energy accumulated by itself exceeds the energy which needs to be overcome by the edge of the condensed liquid droplet 13 to break away from the contact surface of the second side position 15, the condensed liquid droplet 13 moves from the second side position 15 to the first side position 14.
3. The energy to be overcome for the condensate droplets 13 to leave the first side position 14 and the second side position 15 is a first movement energy and a second movement energy, respectively, and the first movement energy is greater than the second movement energy;
4. The energy obtained from the outside and/or the energy accumulated by itself first exceeds the second movement energy, so as to reach the condition of disengagement of the condensed droplets 13 from the second side 15;
5. The condensate droplets 13 move from the second side position 15 to the first side position 14;
6. The condensed droplets 13 remain on the surface of the hydrophobic substrate 11;
7. The edges of the condensed droplets 13 are at a new first side position 14 and a new second side position 15;
8. The energy that the condensed droplets 13 need to overcome to leave the new first side position 14 and the new second side position 15 is a new first movement energy and a new second movement energy, respectively, the new first movement energy being greater than the new second movement energy;
9. The energy obtained from the outside and/or the energy accumulated by itself first exceeds the new second movement energy, the condition that the condensate droplets 13 leave the new second side 15 is reached;
10. The condensate droplets 13 move from the new second side position 15 to the new first side position 14.
on the hydrophobic substrate 11, the condensed liquid droplets 13 nucleate on the surfaces of the protrusions 112 and the hydrophilic surfaces of the protrusions 112, the hydrophilic surfaces of the protrusions 112 are hydrophilic surfaces, the surfaces of the protrusions 112 are hydrophobic surfaces, and the condensed liquid droplets 13 nucleate more easily on the hydrophilic surfaces of the protrusions 112 than on the surfaces of the protrusions 112;
the position of one side of the condensed liquid droplets 13 in the length direction of the hydrophobic substrate 11 or the position of one side close to the middle of the hydrophobic substrate 11 or the position of one side far from the middle of the hydrophobic substrate 11 is a first side position 14, the other side of the condensed liquid droplets 13 is located at a second side position 15, the ratio of the number of the protrusions 112 having the hydrophilic surface contained in the first side position 14 to the total area of the first side position 14 is a first number fraction, the ratio of the number of said protrusions 112 having a hydrophilic surface contained in said second side 15 to the total area of said second side 15 is a second number fraction, said first number fraction being greater than said second number fraction, when the energy taken by the condensed liquid droplets 13 from the outside and/or the energy accumulated by the condensed liquid droplets 13 exceeds the energy to be overcome by the edges of the condensed liquid droplets 13 to separate from the second side positions 15, the condensed liquid droplets 13 move from the second side positions 15 to the first side positions 14.
the hydrophilic artificial nucleation sites 12 described in this embodiment are structures provided on the hydrophobic surface of the hydrophobic substrate 11, and the hydrophilic surfaces of the protrusions 112 are hydrophilic surfaces processed on the tops of the protrusions 112, so that the two structures are different structures.
the embodiment has the following advantages and principles:
1. Easy nucleation in hydrophilic artificial nucleation point 12 department when condensation droplet 13 condenses, with hydrophilic artificial nucleation point 12 setting on hydrophobic base plate 11 to the nucleation speed and the nucleation density of condensation droplet 13 on hydrophobic base plate 11 have been improved, thereby the nucleation process of droplet in the condensation heat transfer process is promoted. By arranging the plurality of hydrophilic artificial nucleation points 12, the nucleation density can be further improved while the nucleation speed is improved.
since the first area fraction is greater than the second area fraction, the energy required to overcome the droplets 13 to disengage from the first side location 14 is greater than the energy required to disengage the droplets 13 from the second side location 15, i.e., the first displacement energy is greater than the second displacement energy. The condensed droplets 13 grow after nucleation, and the energy taken from the outside and/or the energy accumulated by themselves are in an increased state as a whole. The energy obtained by the condensed liquid droplets 13 from the outside and/or the energy accumulated by the condensed liquid droplets 13 reaches the energy to be overcome by the condensed liquid droplets 13 to separate from the second side position 15, so that the condensed liquid droplets 13 separate from the second side position 15, and the effect of promoting the condensed liquid droplets 13 to move from the second side position 15 to the first side position 14 is achieved. After the condensed liquid drops 13 move, the edges of the condensed liquid drops 13 are located at the new first side position 14 and the new second side position 15, and since the energy required to overcome the condensed liquid drops 13 to be separated from the new first side position 14 is larger than the energy required to overcome the condensed liquid drops 13 to be separated from the new second side position 15, the condensed liquid drops 13 are separated from the new second side position 15, and the circulation is performed, so that the process that the condensed liquid drops 13 continuously move towards the direction beneficial to discharge is realized and promoted, the process not only promotes the movement of the condensed liquid drops 13, but also promotes the discharge of the condensed liquid drops 13, and the condensation heat exchange process is promoted.
the relationship between the magnitude of the first movement energy and the second movement energy of the hydrophilic artificial nucleation sites 12 disposed on the surface of the hydrophobic substrate 11 is inferred as follows:
For the first side 14, the energy that needs to be overcome to disengage the edge of the condensate droplet 13 from the contact surface, i.e. the first displacement, is:
For the second side position 15, the energy to be overcome by which the edge of the condensed liquid droplet 13 leaves the contact surface, i.e. the second movement, can be:
Wherein A represents the contact area of the condensed liquid drops 13 in the first side position 14 and the second side position 15 with the surface respectively in the formulas (i) and (ii);a first area fraction and a second area fraction, respectively; gamma raysl、γsvSurface tension between solid phase and liquid phase in the surface region of the hydrophobic substrate 11, and surface tension between solid phase and gas phase, respectively; gamma's'sl、γ′svthe surface tension between the solid phase and the liquid phase and the surface tension between the solid phase and the gas phase in the hydrophilic artificial nucleation site 12 are respectively; gamma raylvIs in liquid phase and gas phasesurface tension of (2).
At the boundary of the condensed liquid drop 13 and the smooth solid surface, the contact angle formed by the tangent line of the surface of the condensed liquid drop 13 and the solid surface is an intrinsic contact angle which is thetaY，θYThe smaller the value, the better the hydrophilicity. According to Young's Equation (Young's Equation), θYAngle and gammasv、γsl、γlvThe relationship of (1) is:
for the surface of the hydrophobic substrate 11 compared to the hydrophilic artificial nucleation sites 12, the hydrophilicity of the hydrophilic artificial nucleation sites 12 is higher than that of the surface of the hydrophobic substrate 11, and the intrinsic contact angle of the surface of the hydrophobic substrate 11 to the condensed liquid droplet 13 is larger than that of the hydrophilic artificial nucleation sites 12, that is:
The distribution density of the hydrophilic artificial nucleation points 12 is gradually increased along the direction perpendicular to the artificial nucleation columns, so that under the condition that the total area of the first side position 14 is the same as that of the second side position 15, the number of the hydrophilic artificial nucleation points 12 in the first side position 14 is greater than that of the hydrophilic artificial nucleation points 12 in the second side position 15. Thus, the first area fraction is greater than the second area fraction, i.e.:
combining the formulas (IV) and (V) with the formulas (I) and (II) to obtain:
G2＜G1……………………………………⑥
i.e. the first movement energy is larger than the second movement energy. Therefore, when the condensed liquid droplets 13 obtain the external energy or the energy accumulated by the condensed liquid droplets 13 exceeds the second movement energy, the edges of the condensed liquid droplets 13 at the second side positions 15 are separated from the surface, so that the condensed liquid droplets 13 move from the second side positions 15 to the first side positions 14, and the movement of the condensed liquid droplets 13 is promoted.
Realized increasing the nucleation density of condensate droplet 13 through a plurality of hydrophilic artifical nucleation points 12, utilized the distribution of hydrophilic artifical nucleation point 12 simultaneously, promoted the removal of condensate droplet 13, made condensate droplet 13 in time discharge to promote condensation heat transfer process, improved the efficiency of condensation heat transfer.
The relationship between the magnitude of the first movement energy and the second movement energy is inferred as follows, for the hydrophilic surface of the surface processing of the projections 112 of the hydrophobic substrate 11 itself:
for the first side 14, the energy that needs to be overcome to disengage the edge of the condensate droplet 13 from the contact surface, i.e. the first displacement, is:
For the second side position 15, the energy to be overcome by which the edge of the condensed liquid droplet 13 leaves the contact surface, i.e. the second movement, can be:
Wherein a represents the areas of the first side position 14 and the second side position 15 in equations (c) and (b), respectively, where the areas of the first side position 14 and the second side position 15 are equal, and all the following embodiments are also equal;is the ratio of the area of the tops of all the microstructure protrusions 112 to the area of the entire substrate. a ist1And at2The ratio of the hydrophilic top area of microstructure protrusion 112 in first side location 14 and second side location 15 to the area of first side location 14 and second side location 15, respectively. Gamma raysl、γsvrespectively is a microstructure bump112The surface tension between the solid phase and the liquid phase on the hydrophobic top surface and the surface tension between the solid phase and the gas phase; gamma's'sl、γ′svRespectively, the surface tension of the microstructure protrusions 112 between the hydrophilic top surface solid phase and the liquid phaseAnd the surface tension between the solid phase and the gas phase; gamma raylvSurface tension between liquid and gas phases.
because the first number fraction is greater than the second number fraction, i.e. at1＞at2Therefore G11＞G12。
The first displacement energy is greater than the second displacement energy and the condensate droplets 13 move from the second side position 15 to the first side position 14
2. The hydrophilic artificial nucleation sites 12 in the same artificial nucleation column are uniformly distributed, so that the condensed liquid drops 13 can move towards the direction vertical to the artificial nucleation column more stably.
3. the protrusions 112 are uniformly arranged on the surface of the substrate 111, and the hydrophilic surface after processing is non-uniform, namely the ratio of the number of the protrusions 112 with the hydrophilic surface contained in the first side position 14 to the total area of the first side position 14 is a first number fraction; the ratio of the number of projections 112 having a hydrophilic surface contained in the second side 15 to the area of the second side 15 is a second number fraction, the first number fraction being greater than the second number fraction, condensation droplets can be nucleated by the hydrophilic surface of the projections 112 and then the drainage of the condensation droplets 13 is facilitated by the wetting gradient surface formed by the projections themselves.
Example 2:
This example differs from example 1 in that:
as shown in fig. 3, the distance between the protrusions 112 at the second side position 15 is greater than the distance between the protrusions 112 at the first side position 14, specifically, the transition direction from the second side position 15 to the first side position 14 is a gradient direction, and the distance difference between the protrusions 112 in the gradient direction is the same or gradually decreases, and is reduced by an equal difference. Here, the difference in pitch is the same or gradually decreases, which means that the pitch between some of the adjacent protrusions 112 is the same, and the pitch between some of the adjacent protrusions 112 is different, and the difference in pitch is a certain value, which is 5 μm.
Specifically, the height of the protrusions 112 is 20 micrometers, and the pitch of the protrusions 112 between adjacent ones is 20 micrometers, or 25 micrometers, or 30 micrometers, or 35 micrometers, or 40 micrometers.
The embodiment has the following advantages and principles:
Not only can the condensation liquid drop be nucleated through the convex hydrophilic surface, but also a wetting gradient can be formed through the non-uniformly arranged convex, and the discharge of the condensation liquid drop is more facilitated.
the distance between the projections 112 of the hydrophobic substrate 11 itself is inferred as follows with respect to the magnitude relationship between the first movement energy and the second movement energy:
For the first side 14, the energy that needs to be overcome to disengage the edge of the condensate droplet 13 from the contact surface, i.e. the first displacement, is:
For the second side position 15, the energy to be overcome by which the edge of the condensed liquid droplet 13 leaves the contact surface, i.e. the second movement, can be:
Wherein a represents the areas of first side bit 14 and second side bit 15 in the formulas ninthly and the r, respectively; the area ratio of the top of microstructure protrusion 112 in first side location 14 and second side location 15 to first side location 14 or second side location 15, respectively. a istThe ratio of the hydrophilic top area of the microstructure protrusion 112 to the entire substrate area. Gamma raysl、γsvThe surface tension of the hydrophobic top surface of the microstructure protrusion 112 between the solid phase and the liquid phase and the surface tension of the solid phase and the gas phase are respectively set; gamma's'sl、γ′svThe surface tension of the hydrophilic top surface of the microstructure protrusions 112 between the solid phase and the liquid phase and the surface tension of the solid phase and the gas phase respectively; gamma raylvSurface tension between liquid and gas phases.
because the distance between the protrusions 112 of the second side 15 is greater than the distance between the protrusions 112 of the first side 14, i.e. the distance between the protrusions 112 of the second side is greater than the distance between the protrusions of the first sideSo G21＞G22。
The first displacement energy is greater than the second displacement energy and the condensate droplets 13 move from the second lateral position 15 to the first lateral position 14.
For the surface-processed hydrophilic surface of the projections 112 of the hydrophobic substrate 11 itself and the pitch of the projections 112 of the hydrophobic substrate 11 itself of the first and second embodiments, in combination, the relationship between the magnitude of the first movement energy and the second movement energy is inferred as follows:
For the first side 14, the energy that needs to be overcome to disengage the edge of the condensate droplet 13 from the contact surface, i.e. the first displacement, is:
for the second side position 15, the energy to be overcome by which the edge of the condensed liquid droplet 13 leaves the contact surface, i.e. the second movement, can be:
Wherein A is in the formulaAndrespectively, the areas of first side position 14 and second side position 15; The area ratio of the top of microstructure protrusion 112 in first side location 14 and second side location 15 to first side location 14 or second side location 15, respectively. a ist1And at2The ratio of the hydrophilic top area of microstructure protrusion 112 in first side location 14 and second side location 15 to the area of first side location 14 and second side location 15, respectively. Gamma raysl、γsvthe surface tension of the hydrophobic top surface of the microstructure protrusion 112 between the solid phase and the liquid phase and the surface tension of the solid phase and the gas phase are respectively set; gamma's'sl、γ′svthe surface tension of the hydrophilic top surface of the microstructure protrusions 112 between the solid phase and the liquid phase and the surface tension of the solid phase and the gas phase respectively; gamma raylvSurface tension between liquid and gas phases.
because of the fact thatat1＞at2therefore G31＞G32，
the first displacement energy is greater than the second displacement energy and the condensate droplets 13 move from the second lateral position 15 to the first lateral position 14.
The rest of this embodiment can refer to embodiment 1, and will not be described herein again.
Example 3:
the difference between the present embodiment and embodiment 1 is that:
the surface of the hydrophobic substrate 11 of this embodiment is a wetting gradient surface, the intrinsic contact angle of the hydrophobic substrate 11 gradually changes from 120 ° to 95 °, the smaller the intrinsic contact angle, the higher the hydrophilicity, and the direction of the increased hydrophilicity of the surface of the hydrophobic substrate 11 is opposite to the direction of the first side position 14 toward the second side position 15.
The embodiment has the following advantages and principles: when the condensed liquid drops 13 are located at the position with lower hydrophilicity, the condensed liquid drops 13 have a tendency to move to the position with higher hydrophilicity, and the effect of promoting the condensed liquid drops to move to the hydrophilic region is achieved. Meanwhile, the surface of the hydrophobic substrate 11 and the hydrophilic artificial nucleation point 12 are utilized to jointly promote the movement of the condensed liquid drops 13, the discharge of the condensed liquid drops 13 is accelerated, the effect of further promoting the movement of the condensed liquid drops 13 is achieved, the condensed liquid drops 13 are timely discharged, the condensation heat exchange process is promoted, and the condensation efficiency is improved.
the rest of this embodiment can refer to embodiment 1, and will not be described herein again.
Example 4:
the difference between the present embodiment and embodiment 1 is that:
The intrinsic contact angle of the surface of the hydrophobic substrate 11 is larger than that of the hydrophilic artificial nucleation sites 12, and the surface of the hydrophobic substrate 11 is a super-hydrophobic surface. The young's contact angle of the superhydrophobic surface is greater than 150 °, and in the present embodiment, 175 ° is adopted as the intrinsic contact angle of the surface of the hydrophobic substrate 11.
the embodiment has the following advantages and principles:
1. the intrinsic contact angle of the surface of the hydrophobic substrate 11 is larger than the intrinsic contact angle of the hydrophilic artificial nucleation sites 12, so that the hydrophilicity of the hydrophilic artificial nucleation sites 12 is higher than that of the hydrophobic substrate 11. The advantage that the condensed liquid drops 13 are easy to nucleate at the hydrophilic artificial nucleation sites 12 is maintained, and at the same time, the condensed liquid drops 13 are easy to detach from the hydrophobic substrate 11 with low hydrophilicity, thereby playing the effect of promoting the movement of the condensed liquid drops 13. The separation of the condensed liquid droplets 13 from the hydrophobic substrate 11 is promoted, the heat exchange during the condensation process is further improved, and the condensation efficiency is improved.
2. By utilizing the advantages that the condensed liquid drops 13 have good fluidity and small adhesive force on the super-hydrophobic surface, the discharging speed of the condensed liquid drops 13 is increased, and the effect of promoting the movement of the condensed liquid drops 13 is achieved.
the rest of this embodiment can refer to embodiment 1, and will not be described herein again.
Example 5:
The difference between the present embodiment and embodiment 1 is that:
as shown in fig. 4, in the present embodiment, the density of the hydrophilic artificial nucleation sites 12 is the lowest in the middle of the surface of the hydrophobic substrate 11, and the density of the hydrophilic artificial nucleation sites 12 is gradually increased from the middle of the surface of the hydrophobic substrate 11 to the periphery. In the present embodiment, the intrinsic contact angle of the surface of the hydrophobic substrate 11 is 120 °.
The embodiment has the following advantages and principles:
The reasoning shows that the condensed liquid drops 13 can move from the position with lower density of the hydrophilic artificial nucleation points 12 to the position with higher density, so that the condensed liquid drops 13 can move from the middle part of the surface of the hydrophobic substrate 11 to the periphery, and the condensed liquid drops can be conveniently collected and discharged while the nucleation density of the condensed liquid drops 13 is increased and the condensed liquid drops 13 are promoted to be discharged to strengthen the condensation heat exchange process.
Example 6:
the difference between the present embodiment and embodiment 4 is that:
The surface of the hydrophobic substrate 11 in this embodiment is a wetting gradient surface, and the hydrophilicity of the wetting gradient surface gradually increases from the lowest distribution density of the hydrophilic artificial nucleation sites 12 to the periphery.
The embodiment has the following advantages and principles:
The surface of the hydrophobic substrate 11 and the hydrophilic artificial nucleation point 12 are used for promoting the movement of the condensed liquid drops 13 together, the discharge of the condensed liquid drops 13 is accelerated, the effect of further promoting the movement of the condensed liquid drops 13 is achieved, and the condensation heat exchange process is strengthened. Meanwhile, the effect of collecting and discharging condensed liquid drops can be achieved.
Example 7:
the difference between the present embodiment and embodiment 1 is that:
in this embodiment, the density of the hydrophilic artificial nucleation sites 12 in the middle of the surface of the hydrophobic substrate 11 is the highest, the density of the hydrophilic artificial nucleation sites 12 is gradually reduced from the middle of the surface of the hydrophobic substrate 11 to the periphery, and the surface of the hydrophobic substrate 11 is provided with a drainage port.
The embodiment has the following advantages and principles: with this arrangement, the area where the density of the hydrophilic artificial nucleation sites 12 is high is smaller than the area where the density of the hydrophilic artificial nucleation sites 12 is low. It can be known from the reasoning that the condensed liquid drops 13 can move from the position with lower density of the hydrophilic artificial nucleation point 12 to the position with higher density, so that the condensed liquid drops 13 are concentrated at the middle part of the surface of the hydrophobic substrate 11 and can be discharged from the surface of the hydrophobic substrate 11 through the water outlet, and the condensed liquid drops 13 can be better promoted to move, so that the condensed liquid drops 13 can be discharged in time, thereby promoting the condensation heat exchange process and improving the condensation efficiency.
the rest of this embodiment can refer to embodiment 1, and will not be described herein again.
The above are only specific embodiments of the present invention, and the protection scope of the present invention is not limited thereby; any replacement and improvement made on the basis of not violating the conception of the utility model belong to the protection scope of the utility model.
Claims (10)
1. The device for enhancing condensation heat exchange is characterized by comprising a hydrophobic substrate (11), wherein the surface of the hydrophobic substrate (11) is a hydrophobic surface;
The hydrophobic substrate (11) is provided with a plurality of hydrophilic artificial nucleation points (12) positioned on the surface of the hydrophobic substrate (11), and the surfaces of the hydrophilic artificial nucleation points (12) are hydrophilic surfaces;
Condensed liquid drops (13) are converged on the surface of the hydrophobic substrate (11), the position of one side of each condensed liquid drop (13) in the length direction of the hydrophobic substrate (11) or the position of one side close to the middle of the hydrophobic substrate (11) or the position of one side far away from the middle of the hydrophobic substrate (11) is a first side position (14), the position of the other side of each condensed liquid drop (13) is a second side position (15), the ratio of the area of hydrophilic artificial nucleation points (12) contained in the first side positions (14) to the total area of the first side positions (14) is a first surface integral number, the ratio of the area of hydrophilic artificial nucleation points (12) contained in the second side positions (15) to the total area of the second side positions (15) is a second surface integral number, and the first surface integral number is larger than the second surface integral number.
2. the device for enhancing condensation heat exchange according to claim 1, wherein a plurality of the hydrophilic artificial nucleation sites (12) are respectively arranged in artificial nucleation columns which are parallel to each other and perpendicular to the movement direction of the condensed liquid droplets (13), and the distribution density of the hydrophilic artificial nucleation sites (12) is gradually increased along the direction perpendicular to the artificial nucleation columns.
3. the apparatus for enhancing condensation heat transfer as set forth in claim 2, wherein the hydrophilic artificial nucleation sites (12) within the same artificial nucleation column are uniformly distributed.
4. the device for enhancing condensation heat exchange as set forth in claim 1, wherein the distribution density of the hydrophilic artificial nucleation sites (12) is gradually decreased or increased from the middle to the periphery.
5. device for enhancing condensation heat transfer according to any of claims 1 to 4, characterized in that the surface of the hydrophobic base plate (11) is a wetting gradient surface, and the increasing hydrophilicity of the surface of the hydrophobic base plate is oriented at an angle of more than 90 ° to the direction of the first side (14) towards the second side (15).
6. the device for enhancing condensation heat exchange as claimed in claim 5, wherein the surface of the hydrophobic substrate (11) is a super-hydrophobic surface.
7. The device for enhancing condensation heat exchange according to any one of claims 1 to 4, wherein the hydrophobic substrate (11) comprises a base (111) and protrusions (112), the protrusions (112) are arranged on the surface of the base (111), the height difference of the protrusions (112) is within one fifth of the height of the protrusions, the height of the protrusions (112) is 5 micrometers to 40 micrometers, and the distance between adjacent protrusions (112) is 10 micrometers to 100 micrometers.
8. The apparatus for enhancing condensation heat transfer as set forth in claim 7 wherein the spacing between said protrusions (112) of said second side portion (15) is greater than the spacing between said protrusions (112) of said first side portion (14).
9. The apparatus for enhancing condensation heat transfer as set forth in claim 7 wherein a portion of said protrusions (112) are formed with a hydrophilic surface, and a ratio of the number of said protrusions (112) having a hydrophilic surface contained in said first side portion (14) to the total area of said first side portion (14) is a first number fraction; the ratio of the number of projections (112) having a hydrophilic surface contained in the second side portion (15) to the area of the second side portion (15) is a second number fraction, and the first number fraction is larger than the second number fraction.
10. The apparatus for enhancing condensation heat transfer as claimed in claim 7, wherein the spacing between the protrusions (112) at the second side (15) is greater than the spacing between the protrusions (112) at the first side (14).
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