CN105363656A - Method for lowering water conveying pipe head losses - Google Patents

Abstract

The invention provides a method for lowering water conveying pipe head losses. An antifriction material is attached or coats the inner wall of a water conveying pipe. The antifriction material is a sharkskin simulating antifriction material or a nanometer super-hydrophobic material. The sharkskin simulating antifriction material can be directly stuck to the surface of the water conveying pipe, the surface of the water conveying pipe can also be coated with a substrate material layer at first so as to improve the bonding force between the sharkskin simulating material and the pipe wall; the surface of the water conveying pipe can be coated with the nanometer super-hydrophobic material directly and can also be coated with a substrate material layer at first so as to improve bonding force between the nanometer material and the pipe wall. The nanometer super-hydrophobic material can be mixed with the nanometer antifriction material for use so as to achieve the purposes of lowering frictional resistance and resisting corrosion; the method can lower the adhesive power and flow resistance of the solid-liquid surface, the hydrophobic performance of the surface of the water conveying pipe is effectively improved, and linear losses in the pipe water conveying process are reduced.

Description

A kind of method reducing the aqueduct loss of flood peak

Technical field

The present invention relates to Hydraulic and Hydro-Power Engineering, hydrographic water resource engineering, water environment field of engineering technology, particularly relate to a kind of method reducing the aqueduct loss of flood peak.

Background technology

Hydroelectric generation is that water can be converted into electric energy, obtains an important means of electric power.China's power station installed capacity has reached 300,000,000 kilowatts (300,000 MW), accounts for 27% of China's generating total amount, occupies an important position in the energy resource structure of China.

Most of hydroelectric generation all needs to use conduit pipe that water is caused hydroelectric generator from reservoir, and the position relationship of diversion pipe range apparent distance reservoir is between tens meters to a few km, and caliber and in-pipe flow amount look generating scale and different.The flowing of high-velocity flow in conduit pipe can cause the loss of flood peak due to the turbulent fluctuation friction between water and tube wall, and according to incompletely statistics, the loss of flood peak of Built hydropower station diversion pipeline section, at 1 ~ 8m, accounts for 1 ~ 8% of gross head.The loss of flood peak consumes water energy, reduces generated energy, causes energy loss.

The aqueduct loss of flood peak comes from the frictional force between the water of flowing and tube wall, and calculation of head losses presses following formula:

Darcy (Darcy) formula $h_f=\mathrm{\λ}\frac{l}{d}\frac{v^2}{2g}---\left(1\right)$

Thank to (Chezy) formula $v=C\sqrt{Ri}---\left(2\right)$

Wherein: $\frac{1}{\sqrt{\mathrm{\λ}}}=-2\lg (\frac{\mathrm{\Δ}}{3.7d}+\frac{2.51}{\mathrm{Re}\sqrt{\mathrm{\λ}}})---\left(3\right)$

$C=\frac{1}{n}{\mathrm{Re}}^y---\left(4\right)$

$y=2.5\sqrt{n}-0.13-0.75\sqrt{R}(\sqrt{n}-0.1)---\left(5\right)$

In formula: h _ffor linear loss, m; λ is frictional resistant coefficient; L is length of pipe section, m; D is that pipeline calculates internal diameter, m; G is acceleration of gravity, m/s ²; C is for thanking to just coefficient; I is hydraulic slope; R is hydraulic radius, m; V is flow velocity, m/s; Re is Reynolds number; N is the coefficient of roughness.

From formula (1) ~ (5), the loss of flood peak and the coefficient of roughness linear, reducing roughness coefficien n by taking measures, friction can be reduced, reduce the loss of flood peak.

Aqueduct reduced the loss of flood peak mainly through reducing flow rate of water flow in the past, increased caliber and realized; In addition, some anti-attrition draft reduction materials such as epoxy resin, spray polyurea etc. also starts to be applied to gas transmission oil pipeline.But, be coated with super hydrophobic material in existing water-supply-pipe and only rest on experimental stage, pipe diameter is little, tubing based on metal pipe material, plastic material, flow rate of water flow is usually between 5 ~ 20m/s.And along with project implementations such as the south water to north, large-scale high head hydroelectric power plant starts to build in succession, the aqueduct being applied to the high head hydroelectric power plants such as water-storage mostly is Large Diameter Pipeline, concrete duct, its surface energy is higher, larger to resistance to water-flow, and the earial drainage max-flow scooter 50m/s of high head hydroelectric power plant, can find out according to formula, the loss of flood peak can with flow velocity square and amplify rapidly, cause larger energy loss.Therefore, the resistance reducing performance, hydrophobic performance etc. of foundation to material of high head hydroelectric power plant are proposed higher requirement, and the technology of the existing reduction loss of flood peak cannot be applicable to the requirement of the reduction loss of flood peak of high-head power station.

Summary of the invention

The object of the invention is to for the deficiencies in the prior art, provide a kind of and reduce wall friction in water-supply-pipe, thus reduce the method for the loss of flood peak.

For achieving the above object, the invention provides a kind of method reducing the aqueduct loss of flood peak, at aqueduct interior finishing or paste one deck antifriction material, this antifriction material is imitative sharkskin antifriction material, nano-sized hydrophobic material or nano superhydrophobic material.

Further, described imitative sharkskin antifriction material is pasted on aqueduct surface in the following manner: 1) use and paste agent and directly to be pasted by imitative sharkskin antifriction material on aqueduct surface; Or 2) first to spray a layer thickness be the base material of 0.02 ~ 0.15mm, re-use and paste agent imitative sharkskin antifriction material is pasted on base material.

Further, described nano-sized hydrophobic material or nano superhydrophobic material are sprayed on aqueduct surface in the following manner: 1) directly nano-sized hydrophobic material or nano superhydrophobic material are coated with and are contained in aqueduct surface, or 2) first spray one deck base material, then coating nano hydrophobic material or nano superhydrophobic material.

Further, described imitative sharkskin antifriction material is that silicon rubber turns over the imitative sharkskin of mould PU (polyurethanes abbreviation polyurethane), silicon rubber turns over the imitative sharkskin of mould PDMS (dimethyl silicone polymer) or polyurethane-base imitates sharkskin.

Further, described nano-sized hydrophobic material or nano superhydrophobic material are nano-organosilicon or its modified resin, nanometer fluororesin or its modified resin one wherein.

Further, described in paste agent be sealing neutral silicone resin, described base material is adhesion promoter, is preferably 3M94 primary coat adhesion promoter.

Further, the nanometer resistant abrasion material of 10-30% is added in described nano superhydrophobic material or nano-sized hydrophobic material, carry out application again after the two is used in combination, reduce frictional resistance and opposing abrasion two objects to reach, described nanometer resistant abrasion material is preferably nanometer Al ₂o ₃/ ZrO ₂epoxy resin resistant abrasion coating.

Further, described coating process comprises brushing, roller coating, dip-coating, aerial spraying, airless spraying and electrostatic spraying etc., different according to tubing during application, can use wherein a kind of or use several application mode simultaneously.

Further, adopt and paste or before the method for application carries out application to aqueduct inwall, surface treatment need be carried out to pipeline.

Further, to aqueduct process, reduce the loss of flood peak, when improving emptying effectiveness, relevant device is adjusted, as power station, need adjust surge shaft and the hydraulic turbine, to adapt to new head.

The antifriction material that the present invention selects is imitative sharkskin antifriction material, nano-sized hydrophobic material or nano superhydrophobic material.

Wherein, know according to research, shark skin shaggy V-arrangement gauffer can the eddy current of ingenious generation water, and greatly reduce the frictional force of current, the current around health are more efficiently flow through, shark is able to travelling fast.In addition, the external surface of sharkskin also has water membrane, and this layer of moisture film is converted to the friction between water and water the friction of water and skin, reduces frictional force in traveling process, plays drag reduction effect.Even if the physical property that this moisture film has a low-surface-energy makes marine organisms be difficult to attachment or to adhere to its cohesion also very little, be easy to be automatically cleared.The structure of imitative sharkskin can simulate this V-arrangement fold, and forms moisture film at aqueduct inner surface, and the frictional force between tube wall and current is reduced, and reduces roughness coefficien, reduces the loss of flood peak.Also can reduce the chance that foreign matter adheres to drain water piping simultaneously, easy to clean.

Nano-sized hydrophobic material abutment face is formed and is greater than 90 °, the surface that roll angle is less than 10 °, nano superhydrophobic material is then formed on contact surface surface to be greater than 150 °, the surface that roll angle is less than 10 °, super hydrophobic surface, as the surface of lotus leaf, can produce longitudinal slip effect, thus reduces the frictional resistance of aqueduct, and then reduction roughness coefficien, reduce the loss of flood peak.Nano-organosilicon used or its modified resin and nanometer fluororesin or its modified resin can make nano-sized hydrophobic material or nano superhydrophobic material according to different process.

Adopt the method for application/paste to carry out application to aqueduct inwall, need before application to carry out surface treatment to pipeline, step is as follows:

(1) mechanical chipping: the inside and outside wall sand papering of pipeline, wipes rusty stain and retains certain roughness;

(2) soak cleaning: adopt nitric acid hydrochloric acid mixed solution, sodium hydroxide solution or deionized water to clear up;

(3) dry: to dry up with cold wind, after drying, wait for application.

After surface treatment, available imitative sharkskin material is pasted water-supply-pipe inwall or is carried out spray dress with nano-sized hydrophobic material, nano superhydrophobic material to water-supply-pipe inwall, coating process comprises brushing, roller coating, dip-coating, aerial spraying, airless spraying and electrostatic spraying etc., different according to tubing during application, can use wherein a kind of or use several application mode simultaneously.

Paste concrete steps as follows:

(1) with brush, the instruments such as cylinder (palpus is without fibre shedding), will paste agent and be evenly coated in aqueduct inner surface, general coating layer thickness is 0.02 ~ 0.04mm.

(2) drying time: drying time general apparent temperature, humidity, coating layer thickness and different.Normal drying time is 1 minute ~ 1 hour, and between dry period, notably coating surface is absolutely not contaminated.

(3) imitative sharkskin material is pasted coating surface, and impose certain pressure, imitative sharkskin material and aqueduct inner surface are fitted tightly.

Application concrete steps are as follows:

(1) can select the methods such as brushing, spraying for large-scale water transmission pipeline, in pipe during spraying, by spray gun spraying, nano-sized hydrophobic/super hydrophobic material or base material are attached to water-supply-pipe inner surface after spray gun atomization; At 60 DEG C of dry 2-8 hours or at room temperature dry 12-48h after spraying.

(2) can the methods such as dip-coating be adopted for the aqueduct that caliber is less, when carrying out dip-coating, nano-sized hydrophobic/super hydrophobic coating or base material be poured in immersion container, leave standstill 3-8min; With slow uniform speed, water-supply-pipe is vertically put into paint liquid, after stopping 20-100s, take out from coating at the same rate, be placed on cleaning and locate drip-dry 10-30min.Control the degree of drying of first time paint film, with the film ensureing coating processed not reason there is sagging after dipping lacquer for the second time, sting the end or the phenomenon such as wrinkling; Water-supply-pipe is reversed 180 °, carry out second time dip-coating as stated above, drip-dry; At 60 DEG C of dry 2-8h or at room temperature dry 12-48h after dip-coating.

When former drain water piping being replaced with the drain water piping prepared according to the inventive method, during to improve emptying effectiveness, need adjust relevant device, as power station, need adjust surge shaft and the hydraulic turbine, to adapt to new head.

Beneficial effect of the present invention is:

The invention provides a kind of method reducing the aqueduct loss of flood peak, by pasting or application antifriction material at aqueduct inwall, reduce the frictional force between tube wall and current, thus the loss of flood peak reduced in water delivery process, in reality test, drag reducing efficiency is maximum reaches 24.6%, breaches the bottleneck of bionical groove structure drag reduction 10%.

Method provided by the invention can be used for power station conduit pipe, aqueduct, oil pipeline, city supply water pipeline, for reducing current frictional resistance, reducing the loss of flood peak, improving operational efficiency.

Accompanying drawing explanation

Fig. 1 is the structural representation that in the present invention, aqueduct inwall directly pasted by imitative sharkskin material.

Fig. 2 first sprays the structural representation that the aqueduct inwall of imitative sharkskin material pasted again by base material in the present invention.

Fig. 3 is the structural representation of nano-sized hydrophobic material or nano superhydrophobic material direct spraying aqueduct inwall in the present invention.

Fig. 4 is the structural representation first spraying the base material aqueduct inwall of coating nano hydrophobic material or nano superhydrophobic material again in the present invention.

Reference numeral:

1: aqueduct; 2: imitative sharkskin material; 3: base material; 4: nano-sized hydrophobic material or nano superhydrophobic material.

Detailed description of the invention

Below in conjunction with each embodiment shown in the drawings, the present invention is described in detail; but should be noted that; these embodiments are not limitation of the present invention; those of ordinary skill in the art are according to these embodiment institute work energy, method or structural equivalent transformations or substitute, and all belong within protection scope of the present invention.

The present invention's polyurethane-base used imitates sharkskin purchased from Beijing Zema New Technology Co., Ltd.

The present invention's silicon rubber used turns over that mould PU imitates sharkskin, silicon rubber turns over mould PDMS to imitate sharkskin is laboratory self-control, and main process is:

1. prepare sharkskin sample: be immersed in the formalin solution of 10% after the meat at the fresh sharkskin back side and muscle being removed; Paved by soaked sharkskin, be sandwiched in the smooth hardboard of smooth surface (as glass) and pave or stretch tight within the barrel, the baking oven being placed in 50 DEG C is dry; Berzona 1311 patching material of about 1cm is coated at the sharkskin back side after the drying, and at the hardboard having the one side lid lastblock smooth surface of shield first squama smooth, pressurize a little and to be put down by patching material lamination, indoor solidification 24h, obtains smooth sharkskin sample.

2. liquid-state silicon gel replica turns over mould: on sharkskin sample, spray appropriate dryness high efficient demoulding agent, the even two component fluid silicone rubbers all of mixing are cast on sharkskin, and be placed in vacuum equipment and vacuumize 30s, then slowly open air valve inflation, the bubble in liquid-state silicon gel is fully discharged; More than cold curing 30min, the then demoulding, as replica grinding tool, transfers to surface micro-structure on PU or PDMS, obtains silicon rubber and turns over mould PU and imitate sharkskin or silicon rubber and turn over mould PDMS and imitate shark.

The present invention's nano-organosilicon used and modified resin, nanometer fluororesin and modified resin thereof are commercially available prod, according to different process, for belonging to nano-organosilicon and modified resin, nanometer fluororesin and the modified resin thereof of nano-sized hydrophobic material, or nano-organosilicon and modified resin, nanometer fluororesin and the modified resin thereof of nano superhydrophobic material can be belonged to.

The present invention adhesion promoter 3M94 used primary coat adhesion promoter is commercially available prod.

The present invention's nanometer resistant abrasion used material nano Al ₂o ₃/ ZrO ₂epoxy resin is purchased from Nanjing Ai Purui nano material Co., Ltd.

Embodiment 1

As shown in Figure 1, imitative sharkskin material 2 is directly pasted aqueduct 1 inwall, imitative sharkskin material used is that silicon rubber turns over mould PU and imitates sharkskin, and detailed process is:

1. surface treatment: the inside and outside wall sand papering of (1) pipeline, wipes rusty stain and retains certain roughness; (2) 2% sodium hydroxide solution is adopted to clear up; (3) dry up with cold wind, after drying, wait for application;

2. paste imitative sharkskin material:

(1) with brush, sealing neutral silicone resin is evenly coated in surface treated aqueduct inner surface, coating layer thickness is 0.03mm.

(2) dry 30 minutes, between dry period, notably coating surface was absolutely not contaminated.

(3) silicon rubber is turned over mould PU to imitate sharkskin and paste coating surface, and impose certain pressure imitative sharkskin and aqueduct inner surface are fitted tightly.

Embodiment 2

As shown in Figure 2, for first at aqueduct 1 inner-wall spraying base material 3, and then paste imitative sharkskin material 2, imitative sharkskin material used is that polyurethane-base imitates sharkskin, and detailed process is:

1. surface treatment, the inside and outside wall sand papering of (1) pipeline, wipes rusty stain and retains certain roughness; (2) deionized water is adopted to clear up; (3) dry up with cold wind, after drying, wait for application;

2. spray base material: 3M94 primary coat adhesion promoter is attached to water-supply-pipe inner surface after spray gun atomization; Coating thickness is 0.1mm, 60 DEG C of dryings 7 hours after spraying;

3. paste imitative sharkskin material:

(1) with brush, sealing neutral silicone resin is evenly coated in surface treated aqueduct inner surface, coating layer thickness is 0.04mm.

(2) dry 40 minutes, between dry period, notably coating surface was absolutely not contaminated.

(3) polyurethane-base is imitated sharkskin and paste coating surface, and impose certain pressure imitative sharkskin material and aqueduct inner surface are fitted tightly.

Embodiment 3

As shown in Figure 3, be nano superhydrophobic material 4 directly application aqueduct 1 inwall, nano superhydrophobic material used is nano-organosilicon, and detailed process is:

1. surface treatment: the inside and outside wall sand papering of (1) pipeline, wipes rusty stain and retains certain roughness; (2) nitric acid of 5% and the hydrochloric acid mixed solution of 5% is adopted to clear up; (3) dry up with cold wind, after drying, wait for application;

2. spray nano superhydrophobic material: nano-organosilicon material is attached to water-supply-pipe inner surface after spray gun atomization; 60 DEG C of dryings 5 hours after spraying.

Embodiment 4

As shown in Figure 4, for first at aqueduct 1 inner-wall spraying base material 3, and then spray nano-sized hydrophobic material 4, to be coated with nano-sized hydrophobic material be modified Nano fluororesin, detailed process is:

1. surface treatment, method is with the step 1 of embodiment 1;

2. spray base material: 3M94 primary coat adhesion promoter is attached to water-supply-pipe inner surface after spray gun atomization; Coating thickness is 0.04mm, at room temperature dry 15h after spraying;

3. dip-coating nano-sized hydrophobic material: add nanometer Al by modified Nano fluororesin powder ₂o ₃/ ZrO ₂pour in immersion container after epoxy resin (the two mass ratio is 4:1) mixes, leave standstill 5min; With slow uniform speed, water-supply-pipe is vertically put into coating, after stopping 60s, take out from coating at the same rate, be placed on clean place's drip-dry 20min.Control the degree of drying of first time paint film, with the film ensureing coating processed not reason there is sagging after dipping lacquer for the second time, sting the end or the phenomenon such as wrinkling; Water-supply-pipe is reversed 180 °, carry out second time dip-coating as stated above, drip-dry; At at room temperature dry 24h after dip-coating.

In nano-sized hydrophobic material or nano superhydrophobic material, add nanometer resistant abrasion material, can realize reducing frictional resistance and opposing abrasion two objects simultaneously.

The method of the reduction loss of flood peak provided by the present invention effectively can reduce the frictional force between tube wall and current, reality test according to same pipeline at the roughness coefficien pasted or before and after application antifriction material, calculate and to paste or the drag reducing efficiency of application antifriction material is not less than 20%, maximumly reach 24.6%, the method breaches the bottleneck of bionical groove structure drag reduction 10%, effectively reduces the loss of flood peak in water delivery process.

The invention provides wall friction in above-mentioned reduction water-supply-pipe, thus reduce method, material and the version of the loss of flood peak.

To those skilled in the art, obviously the invention is not restricted to the details of above-mentioned one exemplary embodiment, and when not deviating from spirit of the present invention or essential characteristic, the present invention can be realized in other specific forms.Therefore, no matter from which point, all should embodiment be regarded as exemplary, and be nonrestrictive, scope of the present invention is limited by claims instead of above-mentioned explanation, and all changes be therefore intended in the implication of the equivalency by dropping on claim and scope are included in the present invention.Any Reference numeral in claim should be considered as the claim involved by limiting.

In addition, be to be understood that, although this description is described according to embodiment, but not each embodiment only comprises an independently technical scheme, this narrating mode of description is only for clarity sake, those skilled in the art should by description integrally, and the technical scheme in each embodiment also through appropriately combined, can form other embodiments that it will be appreciated by those skilled in the art that.

Claims (10)

1. reduce a method for the aqueduct loss of flood peak, it is characterized in that, paste or application one deck antifriction material at aqueduct inwall, this antifriction material is imitative sharkskin antifriction material, nano-sized hydrophobic material or nano superhydrophobic material.

2. the method for the reduction aqueduct according to claim 1 loss of flood peak, it is characterized in that, described imitative sharkskin antifriction material is pasted on aqueduct surface in the following manner: 1) use and paste agent and directly to be pasted by imitative sharkskin antifriction material on aqueduct surface; Or 2) first to spray a layer thickness be the base material of 0.02 ~ 0.15mm, re-use and paste agent imitative sharkskin antifriction material is pasted on base material.

3. the method for the reduction aqueduct according to claim 1 loss of flood peak, it is characterized in that, described nano-sized hydrophobic material or nano superhydrophobic material are sprayed on aqueduct surface in the following manner: 1) directly nano-sized hydrophobic material or nano superhydrophobic material are coated with and are contained in aqueduct surface, or 2) first spray one deck base material, then coating nano hydrophobic material or nano superhydrophobic material.

4. the method for the reduction aqueduct loss of flood peak according to any one of claim 1-3, is characterized in that, described imitative sharkskin antifriction material is that silicon rubber turns over that mould PU imitates sharkskin, PDMS imitates sharkskin or polyurethane-base imitates sharkskin.

5. the method for the reduction aqueduct loss of flood peak according to any one of claim 1-3, is characterized in that, described nano-sized hydrophobic material or nano superhydrophobic material are nano-organosilicon or its modified resin, nanometer fluororesin or its modified resin one wherein.

6. the method for the reduction aqueduct loss of flood peak according to any one of claim 1-3, is characterized in that, described in paste agent be sealing neutral silicone resin, described base material is adhesion promoter, and this adhesion promoter is preferably 3M94 primary coat adhesion promoter.

7. the method for the reduction aqueduct loss of flood peak according to claim 1 or 3, it is characterized in that, the nanometer resistant abrasion material of 10-30% is added in described nano superhydrophobic material or nano-sized hydrophobic material, carry out application again after the two is used in combination, described nanometer resistant abrasion material is preferably nanometer Al ₂o ₃/ ZrO ₂epoxy resin resistant abrasion coating.

8. a kind of method reducing the aqueduct loss of flood peak according to any one of claim 1-3, it is characterized in that, described coating process comprises brushing, roller coating, dip-coating, aerial spraying, airless spraying, electrostatic spraying, different according to tubing during application, can use wherein a kind of or use several application mode simultaneously.

9. a kind of method reducing the aqueduct loss of flood peak according to any one of claim 1-3, is characterized in that, before employing application or the method pasted carry out application to aqueduct inwall, carries out surface treatment to aqueduct, increases cohesive force.

10. a kind of method reducing the aqueduct loss of flood peak according to any one of claim 1-3, it is characterized in that, to aqueduct process, reduce the loss of flood peak, when improving emptying effectiveness, relevant device is adjusted, as power station, need adjust surge shaft and the hydraulic turbine, to adapt to new head.