阅读说明：本技术 一种u型钛管内表面超浸润涂层的制备方法 (preparation method of super-wetting coating on inner surface of U-shaped titanium pipe ) 是由 孙立东 李伟 金鉴 赵凯岐 于 2019-08-27 设计创作，主要内容包括：本发明涉及异型管道内表面涂层制备和流体降阻领域,具体是一种适用于U型钛管内表面的超浸润(超亲水或超疏水)涂层的制备方法。当使用异型管道传输流体时,流体在弯转部分会产生较大的压力损失。针对其内表面进行超疏水涂层制备,可以显著降阻并减小能量损耗,达到流体传输时降阻的目的。本发明以U型钛管为原料,采用一种适用于U型管的同轴阳极氧化法,在U型钛管内表面均匀制备氧化钛纳米管阵列涂层,实现管内表面超浸润涂层改性的目的。本发明的制备方法具有操作简单、适用范围广、实用性强、成本低廉等优点,可广泛应用于异型管流体降阻等领域。(the invention relates to the field of preparation of a coating on the inner surface of a special-shaped pipeline and resistance reduction of fluid, in particular to a preparation method of a super-wetting (super-hydrophilic or super-hydrophobic) coating suitable for the inner surface of a U-shaped titanium pipe. When using profiled piping to transport fluids, the fluids create large pressure losses in the turn around section. The preparation of the super-hydrophobic coating is carried out on the inner surface of the coating, so that the resistance can be obviously reduced, the energy loss can be reduced, and the purpose of reducing the resistance during fluid transmission can be achieved. The invention takes a U-shaped titanium pipe as a raw material, adopts a coaxial anodic oxidation method suitable for the U-shaped pipe, and uniformly prepares a titanium oxide nanotube array coating on the inner surface of the U-shaped titanium pipe, thereby realizing the purpose of modifying the super-wetting coating on the inner surface of the pipe. The preparation method has the advantages of simple operation, wide application range, strong practicability, low cost and the like, and can be widely applied to the fields of special pipe fluid resistance reduction and the like.)

1. a preparation method of a super-wetting coating on the inner surface of a U-shaped titanium pipe is characterized by comprising the following steps:

Cleaning and drying the U-shaped titanium tube (1);

Respectively connecting a first pipe orifice of the three-way pipe I (4) and a first pipe orifice of the three-way pipe II (5) with two pipe orifices of the U-shaped titanium pipe (1);

The flexible carbon fiber wire (2) penetrates into the U-shaped titanium pipe (1); two ends of the flexible carbon fiber wire (2) respectively penetrate out of a second pipe orifice of the three-way pipe I (4) and a second pipe orifice of the three-way pipe II (5);

A plurality of insulating small balls (3) penetrate through the flexible carbon fiber wire (2);

The third pipe orifice of the three-way pipe I (4) and the third pipe orifice of the three-way pipe II (5) are respectively connected with a liquid inlet and a liquid outlet of the liquid storage tank (6) through guide pipes;

Starting a circulating pump to enable the electrolyte I in the liquid storage tank (6) to circularly flow in the U-shaped titanium pipe (1);

The U-shaped titanium tube (1) and the flexible carbon fiber wire (2) are respectively connected with a power supply, and electrochemical etching is carried out under the condition of constant voltage;

Cleaning and drying the U-shaped titanium tube (1);

Assembling a U-shaped titanium pipe (1), a flexible carbon fiber wire (2), an insulating small ball (3), a three-way pipe I (4), a three-way pipe II (5) and a liquid storage tank (6) according to the method in the step 2), and replacing the electrolyte in the liquid storage tank (6) into the electrolyte II;

Starting a circulating pump to enable the electrolyte II in the liquid storage tank (6) to circularly flow in the U-shaped titanium pipe (1);

the U-shaped titanium tube (1) and the flexible carbon fiber wire (2) are respectively connected with a power supply, and anodic oxidation is carried out under the condition of constant voltage;

And 7, cleaning and drying the U-shaped titanium tube (1).

2. The method for preparing the super-wetting coating on the inner surface of the U-shaped titanium pipe, according to claim 1, is characterized in that: after the step 7 is finished, the step,

soaking the U-shaped titanium tube in a low surface energy modifier, drying at room temperature, and annealing.

3. The method for preparing the super-wetting coating on the inner surface of the U-shaped titanium pipe as claimed in claim 1 or 2, wherein the method comprises the following steps: in the steps 3 and 6, the U-shaped titanium tube (1) is used as an anode, and the flexible carbon fiber wire (2) is used as a cathode.

4. The method for preparing the super-wetting coating on the inner surface of the U-shaped titanium pipe, according to claim 1 or 3, is characterized in that: and 3) the electrolyte I is selected from a sodium chloride solution.

5. the method for preparing the super-wetting coating on the inner surface of the U-shaped titanium pipe, according to claim 1 or 3, is characterized in that: and 6) the electrolyte II is selected from a glycol solution of ammonium fluoride and water.

6. The method for preparing the super-wetting coating on the inner surface of the U-shaped titanium pipe as claimed in claim 2 or 3, wherein the method comprises the following steps: and 8. the solute of the low surface energy modifier is one of stearic acid, lauric acid and fluorosilane, and the solvent is one of ethanol and normal hexane.

Technical Field

the invention relates to the field of preparation of a coating on the inner surface of a special-shaped pipeline and resistance reduction of fluid, in particular to a preparation method of a super-wetting (super-hydrophilic or super-hydrophobic) coating suitable for the inner surface of a U-shaped titanium pipe.

Background

The U-shaped pipe is a common engineering component and is widely applied to the fields of fluid transmission, condensation heat transfer and the like. When fluid flows through the U-shaped pipe, the resistance coefficient is increased due to the change of the flow velocity direction; especially, under the condition that the bending radius of the U-shaped pipe is far larger than the pipe diameter, the resistance coefficient is obviously increased, and the energy consumption of the input end is increased. The super-hydrophobic coating is prepared on the inner surface of the U-shaped pipe, so that the flow resistance can be effectively reduced, and the method has important engineering application significance. However, due to the special shape and small size of the U-shaped pipe, modifying the super-wetting coating and adjusting the uniformity of the super-wetting coating on the inner surface of the U-shaped pipe have great challenges. The invention provides a coaxial anodizing method for a U-shaped pipe, which can uniformly prepare a super-wetting coating on the inner surface of the U-shaped pipe, greatly reduce flow resistance and has wide application prospect in the field of long-distance fluid transportation.

Disclosure of Invention

The invention aims to provide a preparation method of a super-wetting coating on the inner surface of a U-shaped titanium pipe, which is characterized by comprising the following steps of:

Cleaning and drying the U-shaped titanium tube.

And 2, respectively connecting the first pipe orifice of the three-way pipe I and the first pipe orifice of the three-way pipe II with the two pipe orifices of the U-shaped titanium pipe.

the flexible carbon fiber wire penetrates into the U-shaped titanium pipe. Two ends of the flexible carbon fiber wire respectively penetrate out of the second pipe orifice of the three-way pipe I and the second pipe orifice of the three-way pipe II.

A plurality of insulating small balls penetrate through the flexible carbon fiber.

The third pipe orifice of the three-way pipe I and the third pipe orifice of the three-way pipe II are respectively connected with a liquid inlet and a liquid outlet of the liquid storage tank through guide pipes.

And 3, starting the circulating pump to enable the electrolyte I in the liquid storage tank to circularly flow in the U-shaped titanium pipe.

And respectively connecting the U-shaped titanium tube and the flexible carbon fiber wire with a power supply, and performing electrochemical etching under the condition of constant voltage.

and 4, cleaning and drying the U-shaped titanium tube.

And 5, assembling the U-shaped titanium pipe, the flexible carbon fiber wire, the insulating ball, the three-way pipe I, the three-way pipe II and the liquid storage tank according to the method in the step 2, and replacing the electrolyte in the liquid storage tank with the electrolyte II.

And 6, starting a circulating pump to enable the electrolyte II in the liquid storage tank to circularly flow in the U-shaped titanium pipe.

And the U-shaped titanium tube and the flexible carbon fiber wire are respectively connected with a power supply, and anodic oxidation is carried out under the condition of constant voltage.

And 7, cleaning and drying the U-shaped titanium tube.

Further, after the step 7), the U-shaped titanium tube is soaked by the low surface energy modifier, dried at room temperature and annealed in the step 8.

Further, in the steps 3) and 6, the U-shaped titanium tube is used as an anode, and the flexible carbon fiber wire is used as a cathode.

Further, the electrolyte I in the step 3) is selected from sodium chloride solution.

further, the electrolyte II in the step 6) is selected from a glycol solution of ammonium fluoride and water.

Further, in the step 8), the solute of the low surface energy modifier is one of stearic acid, lauric acid and fluorosilane, and the solvent is one of ethanol and n-hexane.

Compared with the prior art, the invention has the following remarkable advantages and beneficial effects:

1. the titanium dioxide nanotube coating with the super-hydrophobic effect is prepared by using the U-shaped titanium tube as a raw material and adopting a coaxial anodic oxidation method, and has the advantages of good hydrophobic effect, simple preparation process and low cost.

2. The whole preparation process has the industrial and practical characteristics of low equipment price, low and easily obtained raw material cost, simple and convenient operation process and the like.

3. the super-hydrophobic coating prepared on the inner surface of the U-shaped pipe is uniform and free of defects, and has a remarkable resistance reducing effect.

In a word, the invention takes the U-shaped titanium tube as a research object, and adopts a coaxial anodic oxidation method to prepare the titanium dioxide nanotube coating which has rolling super-hydrophobic effect and is uniformly distributed on the inner surface of the U-shaped titanium tube. The titanium dioxide nanotube coating has good binding force with the surface of titanium metal, high physical and chemical stability and rolling super-hydrophobic property, can obviously reduce the energy loss of fluid flowing through a bent pipe, and achieves the effect of obviously reducing resistance of the transmitted fluid.

Drawings

FIG. 1 is a schematic view of an anodizing apparatus for the inner surface of a U-shaped titanium pipe.

Fig. 2 is a dimension example of a U-shaped titanium pipe.

FIG. 3 is a scanning electron microscope image of the surface topography of the U-shaped titanium tube after electrochemical etching.

FIG. 4 is a scanning electron microscope image of the surface morphology of the U-shaped titanium tube after anodization.

FIG. 5 is a high-power scanning electron microscope image of the surface morphology of the U-shaped titanium tube after anodic oxidation.

FIG. 6 shows the statistical results of the uniformity of the super-wetting nanotube coating on the inner surface of the U-shaped titanium tube.

FIG. 7 shows the results of the measurement of the static contact angle of the inner surface of the titanium tube: the left is an original titanium tube, and the right is a super-hydrophobic titanium tube.

FIG. 8 shows the results of the resistance reduction test of U-tubes: the left is an original titanium tube, and the right is a super-hydrophobic titanium tube.

in the figure: the device comprises a U-shaped titanium pipe (1), a flexible carbon fiber wire (2), an insulating small ball (3), a three-way pipe I (4), a three-way pipe II (5) and a liquid storage tank (6).

Detailed Description

The present invention is further illustrated by the following examples, but it should not be construed that the scope of the above-described subject matter is limited to the following examples. Various substitutions and alterations can be made without departing from the technical idea of the invention and the scope of the invention is covered by the present invention according to the common technical knowledge and the conventional means in the field.

a preparation method of a super-wetting coating on the inner surface of a U-shaped titanium pipe is characterized by comprising the following steps:

in the embodiment, the inner diameter of the U-shaped titanium pipe 1 to be processed is 3-30 mm, and the ratio of the bending diameter to the inner diameter of the pipe is 0.5-30. And sequentially carrying out ultrasonic cleaning on the U-shaped titanium tube 1 by using a detergent, tap water, isopropanol, deionized water and alcohol for 10-30 min. And then drying treatment is carried out. During drying treatment, the mixture is firstly dried by a nitrogen spray gun and then is kept in an oven for 0.5 to 10 hours at the temperature of 40 to 110 ℃.

and 2, respectively connecting a first pipe orifice of the three-way pipe I4 and a first pipe orifice of the three-way pipe II5 with two pipe orifices of the U-shaped titanium pipe 1. Referring to fig. 1, a three-way pipe I4 and a three-way pipe II5 are fixed above the U-shaped titanium pipe 1. The U-shaped titanium tube 1 is fixed by a bracket. The first pipe orifice of the three-way pipe I4 and the first pipe orifice of the three-way pipe II5 are both punched down and are tightly connected with the through U-shaped titanium pipe 1, and liquid flowing through the pipe cannot seep out.

The flexible carbon fiber wires 2 penetrate into the U-shaped titanium pipe 1. Two ends of the flexible carbon fiber wire 2 respectively penetrate out of the second pipe orifice of the three-way pipe I4 and the second pipe orifice of the three-way pipe II 5. The diameter of the flexible carbon fiber filament 2 is 0.1-1 mm. Referring to fig. 1, the second orifice of tee I4 and the second orifice of tee II5 were punched up,

a plurality of insulating pellets 3 penetrate through the flexible carbon fiber wire 2 and are assembled according to the figure 1, and the rigid insulating pellets with holes are used as supports and fixed on the flexible carbon fiber wire 2 so as to ensure the coaxiality of the cathode and the anode and realize the coaxial anodic oxidation configuration of the inner surface of the U-shaped titanium pipe; the rigid porous insulating pellets are made of one of polytetrafluoroethylene, polymethyl methacrylate and polypropylene, the diameter of the rigid porous insulating pellets is close to or equal to the inner diameter of the U-shaped pipe 1 (the rigid porous insulating pellets can pass through the inner cavity of the U-shaped pipe 1), and the placing distance of the pellets is 5-100 mm.

The third pipe orifice of the three-way pipe I4 and the third pipe orifice of the three-way pipe II5 are respectively connected with a liquid inlet and a liquid outlet of the liquid storage tank 6 through guide pipes. Referring to FIG. 1, reservoir 6 is fixed above tee I4 and tee II5, with the third port of tee I4 being at the side (horizontal port) and the third port of tee II5 being at the side (horizontal port).

And 3, starting the circulating pump to enable the electrolyte I in the liquid storage tank 6 to circularly flow in the U-shaped titanium tube 1. The electrolyte I is one of sodium chloride, potassium chloride and potassium bromide solution with the concentration of 0.05-1 mol/L, and the circulating flow rate of the electrolyte is 30-100 mL/min.

and respectively connecting the U-shaped titanium tube 1 and the flexible carbon fiber wire 2 with a power supply, taking the U-shaped titanium tube 1 as an anode and the flexible carbon fiber wire 2 as a cathode, and performing electrochemical etching under the condition of constant voltage. The voltage of the electrochemical etching is 10-150V, and the etching time is 1-15 h.

Washing the U-shaped titanium tube 1 with deionized water, and drying, wherein the drying operation is the same as the step 1);

And 5, assembling the U-shaped titanium pipe 1, the flexible carbon fiber wire 2, the insulating small ball 3, the three-way pipe I4, the three-way pipe II5 and the liquid storage tank 6 according to the method in the step 2, and replacing the electrolyte in the liquid storage tank 6 with the electrolyte II.

And 6, starting the circulating pump to make the electrolyte II in the liquid storage tank 6 circularly flow in the U-shaped titanium tube 1. The electrolyte II is a glycol solution containing 0.1 to 1 wt% of ammonium fluoride (or one of sodium fluoride and hydrogen fluoride) and 1 to 25 vol% of water.

The U-shaped titanium tube 1 and the flexible carbon fiber wire 2 are respectively connected with a power supply, the U-shaped titanium tube 1 is used as an anode, the flexible carbon fiber wire 2 is used as a cathode, and anodic oxidation is carried out under the condition of constant voltage. The voltage of anodic oxidation is 20-80V, and the time is 3-15 h.

Washing the U-shaped titanium tube 1 with deionized water, and drying, wherein the drying operation is the same as the step 1);

Soaking the U-shaped titanium tube in a low surface energy modifier. The soaking time is 0.5-2 h, the solute of the low-surface-energy modifier is one of stearic acid, lauric acid and fluorosilane, the solvent is one of ethanol and n-hexane, and the content of the solute component is 1-10 vol%. The solute of the low surface energy modifier is one of stearic acid, lauric acid and fluorosilane, and the solvent is one of ethanol and normal hexane.

And (3) after drying at room temperature, annealing treatment is carried out in a muffle furnace at the temperature of 80-110 ℃, and the annealing time is 0.5-10 h.