CN101694679A - Flow passage structure design method for anti-clogging drip irrigation emitter - Google Patents

Abstract

The invention discloses a flow passage structure design method for an anti-clogging drip irrigation emitter. The method is based on computational fluid dynamics CFD and particle image velocimetry PIV, corrects flow passage structure parameters by means of combining CFD simulation, LRP test sample fast manufacturing and PIV visualized test, processes samples, performs a muddy water anti-clogging test according to relevant international standards, and finally realizes product structure setting and mode opening production. The method can remarkably improve anti-clogging property of the emitter. The method is adopted to perform quadratic optimization of a ladder-type flow passage structure of the drip irrigation emitter and standardize optimizing parameters, thereby normal irrigation days of the emitter are added to 11 days from 6 days before the optimization; maximum sand content is decreased to about 5 % from over 60 %; and anti-clogging property of the emitter is remarkably improved.

Description

A kind of flow passage structure design method for anti-clogging drip irrigation emitter

Technical field

The present invention relates to a kind of flow passage structure design method for anti-clogging drip irrigation emitter, belong to water-saving irrigation, ecological construction and agricultural equipment manufacturing technology field.

Background technology

Stop up is the crucial difficult problem of puzzlement drip irrigation technique development always.Descend because of obstruction causes the drip irrigation system life-span, use cost improves, and irrigation quality descends.The reason that results in blockage mainly is because irrational flow passage structure form except that water quality.For this reason, the anti-obstruction design of research drip emitter is for improving lifetime of system, save cost, improving irrigation quality tool significance.

For addressing the above problem, forefathers have also proposed many flow passage structure design methods, and for example, main channel thought in the application runner reduces the method in 0 flow velocity zone in the runner, reduces the interior vortex regional arrangement of runner etc.Above-mentioned these methods provide the exploration that is highly profitable for the blockage problem that solves douche, but all be difficult to fundamentally eliminate blockage problem, and the practical operation difficulty of above-mentioned Optimization Design is higher, and some has sacrificed the hydraulic performance of douche when improving anti-blockage capability.In addition, patent of invention " a kind of anti-block designing method of drip irrigation tool based on two-phase simulated flow " (ZL 200610018493.7) provides a kind of anti-block designing method based on two-phase simulated flow, the feature of this method is be criterion not occur in the runner that solid particle piles up, and is primarily aimed at rhombus and streams labyrinth flow-path version; Though the method that this patent of invention provides antagonism is stopped up design reference is provided, determination methods is not concrete, and the scope of adaptation is less.In addition, this patent of invention mainly relies on method for numerical simulation in design process, and visual inspection that shortage can be verified and analysis means are difficult to guarantee result's accuracy.

Summary of the invention

Defective or deficiency at above-mentioned prior art existence, the objective of the invention is to, a kind of flow passage structure design method for anti-clogging drip irrigation emitter is provided, can be used for designing various anti-obstruction runner versions, not sacrifice the douche hydraulic performance is prerequisite, improves the douche anti-blockage capability.

In order to realize above-mentioned task, the present invention takes following technical solution:

A kind of flow passage structure design method for anti-clogging drip irrigation emitter is characterized in that: comprise the following steps:

The first step, according to designing requirement, determine preliminary clogging drip irrigation emitter flow passage structure form and parameter, that flow passage structure is selected is trapezoidal, rectangle or curved tooth type labyrinth structure, width of flow path is between 0.6mm～1.2mm, flow channel depth is 0.6mm～1.0mm, and according to the requirement of CFD numerical simulation software, selects following mathematical model

$\left\{\begin{array}{c}\frac{\&PartialD;}{{\&PartialD;x}_k}({\mathrm{\&rho;u}}_k\&PartialD;\stackrel{\&OverBar;}{u_i{u}_j})=P_{\mathrm{ij}}+{\mathrm{\&phi;}}_{\mathrm{ij}}+\frac{\&PartialD;}{{\&PartialD;x}_k}(\frac{{\mathrm{\&mu;}}_t}{{\mathrm{\&sigma;}}_k}\frac{\&PartialD;\stackrel{\&OverBar;}{u_i^{\&prime;}{u}_j^{\&prime;}}}{{\&PartialD;x}_k}+\mathrm{\&mu;}\frac{\&PartialD;\stackrel{\&OverBar;}{u_i^{\&prime;}{u}_j^{\&prime;}}}{{\&PartialD;x}_k})-\frac{2}{3}\mathrm{\&rho;\&epsiv;}{\mathrm{\&delta;}}_{\mathrm{ij}}\\ P=-\mathrm{\&rho;}(\stackrel{\&OverBar;}{u_i^{\&prime;}{u}_k^{\&prime;}}\frac{{\&PartialD;u}_j}{{\&PartialD;x}_k}+\stackrel{\&OverBar;}{u_j^{\&prime;}{u}_k^{\&prime;}}\frac{\&PartialD;u_i}{{\&PartialD;x}_k})\\ {\mathrm{\&phi;}}_{\mathrm{ij},1}=-{\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="H2009102184206E0000033.png"\; state="\{\{state\}\}">C</figure-callout>}}_1\mathrm{\&rho;}\frac{\mathrm{\&epsiv;}}{k}(\stackrel{\&OverBar;}{u_i^{\&prime;}{u}_j^{\&prime;}}-\frac{2}{3}k{\mathrm{\&delta;}}_{\mathrm{ij}})\\ {\mathrm{\&phi;}}_{\mathrm{ij},2}=-C_2(P_{\mathrm{ij}}-\frac{2}{3}{P}_k{\mathrm{\&delta;}}_{\mathrm{ij}})\end{array}\right.$

Wherein P is for producing item; φ _IjBe the ess-strain item; C ₁, C ₂Be coefficient, and C ₁=1.8, C ₂=0.6 draws corresponding physical model, and divides grid, and number of grid should be not less than 5000;

In CFD software, carry out the single-phase flow numerical simulation then, determine the hydraulic performance of preliminary Antiplugging drip irrigation irrigator flow passage structure parameter runner,, promptly utilize numerical evaluation to obtain flow and pressure, according to q=kh if hydraulic performance can meet design requirement ^xReturn, the fluidised form index that obtains is about at 0.5～0.65 o'clock, then enters next step design;

Second step, carry out CFD solid, liquid two-phase flow numerical experiments, the particle random orbit model of selecting during simulation is:

$\left\{\begin{array}{c}\frac{{\mathrm{du}}_s}{\mathrm{dt}}=\frac{1}{{\mathrm{\&tau;}}_s}(\stackrel{\&OverBar;}{u}+u^{\&prime;}-u_s)\\ \frac{{\mathrm{dv}}_s}{\mathrm{dt}}=\frac{1}{{\mathrm{\&tau;}}_s}(\stackrel{\&OverBar;}{v}+v^{\&prime;}-v_s)\\ \frac{{\mathrm{dw}}_s}{\mathrm{dt}}=\frac{1}{{\mathrm{\&tau;}}_s}(\stackrel{\&OverBar;}{w}+w^{\&prime;}-w_s)+g-\frac{{\mathrm{\&rho;}}_{l}g}{{\mathrm{\&rho;}}_s}\end{array}\right.$

U wherein _s, v _s, w _sBe the component of three direction particle speeds, m/s; ρ _sBe particle density, kg/m ^-3ρ _lBe fluid density, kg/m ^-3U, v, w are respectively the component of the liquid mean flow rate of three directions, m/s; U ', v ', w ' are respectively the component of the liquid turbulence fluctuation velocity of three directions, m/s; T is the time, s;

Determine the regularity of distribution of solid particle in the runner then by numerical evaluation, and draw the isogram of solid particulate distributions;

In the 3rd step,, thereby redefine the flow passage structure parameter with 4% solid content isoline correction flow path boundary;

In the 4th step,, carry out the CFD numerical simulation according to second step, the 3rd step once more, till reaching designing requirement to the flow passage structure that redefines;

The 5th step, the douche runner of double optimization design is used the laser Rapid Manufacturing Technology be processed into high transparent test model, make up the visual test unit of particle rapidity imager, and utilize the visual test platform of particle rapidity imager to analyze the practical operation situation of solid particle and fluid, if the flow passage structure parameter in practical operation situation and the 3rd step is basic identical, then carry out next step, otherwise the correcting principle parameter is again since second step;

The visual test platform of described particle rapidity imager comprises tank at least, submersible pump, and tensimeter, light source, the test specimen model, high-speed camera and computer, described tank volume is 30L～50L; The diving lift of pump is 0.5m～12m, and flow is 1L/h～6L/h; The tensimeter error is the 2cm water column; Light source is the news lamp of 1500w; The material penetrability of test specimen model is greater than 92%; The shooting speed of high-speed camera is greater than 1000 frame/seconds;

Described tank, submersible pump, valve, tensimeter, the test specimen model links to each other successively with measuring cup, and light source is positioned at test specimen model top, and high-speed camera is positioned at test specimen model below, and high-speed camera links to each other with computer simultaneously;

In the 6th step, according to the anti-blocking test standard in the world, carry out the muddy water verification experimental verification, and, obtain the flow passage structure of standardized Antiplugging drip irrigation irrigator according to the test findings approved product.

The present invention is based on and calculate hydrodynamics (Computational Fluid Dynamics, hereinafter to be referred as CFD), particle rapidity imager (Particle Image Velocimetry, hereinafter to be referred as PIV) make (Laser Ripad Prototyping fast with laser, hereinafter to be referred as LRP) etc. technology, make up the anti-design platform technology and method that stops up of douche flow passage structure parameter, simulate by CFD, the LRP test specimen is made fast, the method that the PIV visual testing combines is carried out the correction of flow passage structure parameter, and then carry out sample and process, carry out the anti-blocking test of muddy water according to relevant international standard, realize product structure typing and die sinking production at last.The douche flow passage structure of this method design can be implemented on the basis that does not reduce hydraulic performance, improves its anti-blockage capability.Utilize the method that drip emitter ladder type flow passage structure is carried out double optimization, and, be increased to 11 days in 6 days before douche normal irrigation fate is never optimized, and maximum sediment concentration is from dropping to more than 60% about 5% behind the parameters optimization execution standardization; Obviously bring up to the performance of anti-blockage of douche.

Description of drawings

Fig. 1 is the visual test platform test unit of particle rapidity imager.

Fig. 2 stops up design flow diagram for drip emitter is anti-;

Fig. 3 is trapezoidal labyrinth flow-path version and structural parameters;

Fig. 4 is the solid particulate distributions isogram;

Fig. 5 runner solid particle motion PIV observed result;

Fig. 6 is according to Fig. 4 isoline 0.04 revised flow passage structure form

Fig. 7 is revised solid particulate distributions isogram;

Fig. 8 is before optimizing and optimizes back performance of anti-blockage test comparison figure;

Wherein the numeral among Fig. 1 is represented respectively: tank (1), submersible pump (2), valve (3), tensimeter (4), light source (5), test specimen model (6), measuring cup (7), high-speed camera (8) and computer (9).

The present invention is described in further detail below in conjunction with drawings and Examples.

Embodiment

According to technical scheme of the present invention, a kind of flow passage structure design method for anti-clogging drip irrigation emitter specifically comprises the following steps:

The first step, according to designing requirement, determine preliminary flow passage structure form and parameter, that flow passage structure is selected is trapezoidal, rectangle or curved tooth type labyrinth structure, width of flow path is between 0.6mm～1.2mm, flow channel depth is 0.6mm～1.0mm, and according to the requirement of CFD numerical simulation software, selects following mathematical model

$\left\{\begin{array}{c}\frac{\&PartialD;}{{\&PartialD;x}_k}({\mathrm{\&rho;u}}_k\&PartialD;\stackrel{\&OverBar;}{u_i{u}_j})=P_{\mathrm{ij}}+{\mathrm{\&phi;}}_{\mathrm{ij}}+\frac{\&PartialD;}{{\&PartialD;x}_k}(\frac{{\mathrm{\&mu;}}_t}{{\mathrm{\&sigma;}}_k}\frac{\&PartialD;\stackrel{\&OverBar;}{u_i^{\&prime;}{u}_j^{\&prime;}}}{{\&PartialD;x}_k}+\mathrm{\&mu;}\frac{\&PartialD;\stackrel{\&OverBar;}{u_i^{\&prime;}{u}_j^{\&prime;}}}{{\&PartialD;x}_k})-\frac{2}{3}\mathrm{\&rho;\&epsiv;}{\mathrm{\&delta;}}_{\mathrm{ij}}\\ P=-\mathrm{\&rho;}(\stackrel{\&OverBar;}{u_i^{\&prime;}{u}_k^{\&prime;}}\frac{{\&PartialD;u}_j}{{\&PartialD;x}_k}+\stackrel{\&OverBar;}{u_j^{\&prime;}{u}_k^{\&prime;}}\frac{\&PartialD;u_i}{{\&PartialD;x}_k})\\ {\mathrm{\&phi;}}_{\mathrm{ij},1}=-{\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="H2009102184206E0000033.png"\; state="\{\{state\}\}">C</figure-callout>}}_1\mathrm{\&rho;}\frac{\mathrm{\&epsiv;}}{k}(\stackrel{\&OverBar;}{u_i^{\&prime;}{u}_j^{\&prime;}}-\frac{2}{3}k{\mathrm{\&delta;}}_{\mathrm{ij}})\\ {\mathrm{\&phi;}}_{\mathrm{ij},2}=-C_2(P_{\mathrm{ij}}-\frac{2}{3}{P}_k{\mathrm{\&delta;}}_{\mathrm{ij}})\end{array}\right.$

Wherein, P is for producing item; φ _IjBe the ess-strain item; C ₁, C ₂Be coefficient, and C ₁=1.8, C ₂=0.6 draws corresponding physical model, and divides grid, and number of grid is not less than 5000.

In CFD software, carry out the single-phase flow numerical simulation, determine the hydraulic performance of this structural parameters runner,, promptly utilize numerical evaluation to obtain flow and pressure, according to q=kh if hydraulic performance can meet design requirement ^xReturn, the fluidised form index that obtains is about at 0.5～0.65 o'clock, then enters next step design;

Second step, carry out CFD solid, liquid two-phase flow numerical experiments, the particle random orbit model of selecting during simulation is:

$\left\{\begin{array}{c}\frac{{\mathrm{du}}_s}{\mathrm{dt}}=\frac{1}{{\mathrm{\&tau;}}_s}(\stackrel{\&OverBar;}{u}+u^{\&prime;}-u_s)\\ \frac{{\mathrm{dv}}_s}{\mathrm{dt}}=\frac{1}{{\mathrm{\&tau;}}_s}(\stackrel{\&OverBar;}{v}+v^{\&prime;}-v_s)\\ \frac{{\mathrm{dw}}_s}{\mathrm{dt}}=\frac{1}{{\mathrm{\&tau;}}_s}(\stackrel{\&OverBar;}{w}+w^{\&prime;}-w_s)+g-\frac{{\mathrm{\&rho;}}_{l}g}{{\mathrm{\&rho;}}_s}\end{array}\right.$

Wherein, u _s, v _s, w _sBe the component of three direction particle speeds, m/s; ρ _sBe particle density, kg/m ^-3ρ _lBe fluid density, kg/m ^-3U, v, w are respectively the component of the liquid mean flow rate of three directions, m/s; U ', v ', w ' are respectively the component of the liquid turbulence fluctuation velocity of three directions, m/s; T is the time, s;

Determine the regularity of distribution of solid particle in the runner then by numerical evaluation, and draw the isogram of solid particulate distributions;

The 3rd, select 4% solid content isoline correction flow path boundary, redefine the flow passage structure parameter;

The 4th, to the flow passage structure that redefines, carry out the CFD numerical simulation according to second step, the 3rd step once more, till reaching designing requirement;

The 5th, the douche runner of double optimization design is used the LRP technology be processed into high transparent test model, make up the visual test unit of PIV (Fig. 1), and utilize PIV to analyze the practical operation situation of solid particle and fluid, if actual effect and the 3rd step is basic identical, then carry out next step, otherwise the correcting principle parameter is again since second step;

The visual test platform of described particle rapidity imager comprises tank 1 at least, submersible pump 2, and tensimeter 4, light source 5, test specimen model 6, high-speed camera 8 and computer 9, wherein tank 1 volume is 30L～50L; Submersible pump 2 lifts are 0.5m～12m, and flow is 1L/h～6L/h; Tensimeter 4 errors are the 2cm water column; Light source 5 is the news lamp of 1500w; The material penetrability of test specimen model 6 is greater than 92%; The shooting speed of high-speed camera 8 is greater than 1000 frame/seconds;

Described tank 1, submersible pump 2, valve 3, tensimeter 4, test specimen model 6 links to each other successively with measuring cup 7, and light source 5 is positioned at test specimen model 6 tops, and high-speed camera 8 is positioned at test specimen model 6 belows, and high-speed camera 8 links to each other with computer 9 simultaneously;

The 6th step, mfg. moulding die, converted products according to the anti-blocking test standard in the world, carries out the muddy water verification experimental verification, and according to the test findings approved product.

The design implementation example:

Follow above-mentioned technical step of the present invention, the applicant has designed a kind of trapezoidal labyrinth Antiplugging drip irrigation irrigator flow passage structure, and its concrete simulated experiment effect is as follows.

Fig. 3 is certain trapezoidal labyrinth flow-path structure and structural parameters, draw the CFD numerical simulator according to the method described above, carry out solid then, liquid two-phase flow numerical experiments, obtain solid particulate distributions isogram as Fig. 4, and make corresponding visual physical model and carry out PIV observation experiment (Fig. 5), choose less isoline among Fig. 4 (0.04 isoline) in conjunction with PIV observation and carry out the border correction, revised model is carried out numerical model design (Fig. 6), solid, liquid two-phase flow numerical experiments has obtained new solid particle isoline distribution plan (Fig. 7), after the making physical model carries out PIV observation checking, the mold developing production sample carries out the anti-blocking test of muddy water, the results are shown in Figure 8.The runner maximum sediment concentration drops to about 5% (Fig. 7) from prototype (Fig. 4) more than 60%, the design discharge of this runner is 2.2l/h, when flow is reduced to 1.65l/h when following, promptly think and stop up, test findings shows that the lasting irrigation time of original shape is 5-6 days, is 11-13 days and optimize back lasting irrigation fate, lasting irrigation time is multiplied, and its performance of anti-blockage significantly improves.

Claims (1)

1. a flow passage structure design method for anti-clogging drip irrigation emitter is characterized in that: comprise the following steps:

The first step, according to designing requirement, determine preliminary clogging drip irrigation emitter flow passage structure form and parameter, that flow passage structure is selected is trapezoidal, rectangle or curved tooth type labyrinth structure, width of flow path is between 0.6mm～1.2mm, flow channel depth is 0.6mm～1.0mm, and according to the requirement of CFD numerical simulation software, selects following mathematical model:

$\left\{\begin{array}{c}\frac{\&PartialD;}{{\&PartialD;x}_k}({\mathrm{\&rho;u}}_k\&PartialD;\stackrel{\&OverBar;}{u_i{u}_j})=P_{\mathrm{ij}}+{\mathrm{\&phi;}}_{\mathrm{ij}}+\frac{\&PartialD;}{{\&PartialD;x}_k}(\frac{{\mathrm{\&mu;}}_t}{{\mathrm{\&sigma;}}_k}\frac{\&PartialD;\stackrel{\&OverBar;}{u_i^{\&prime;}{u}_j^{\&prime;}}}{{\&PartialD;x}_k}+\mathrm{\&mu;}\frac{\&PartialD;\stackrel{\&OverBar;}{u_i^{\&prime;}{u}_j^{\&prime;}}}{{\&PartialD;x}_k})-\frac{2}{3}{\mathrm{\&rho;\&epsiv;\&delta;}}_{\mathrm{ij}}\\ P=-\mathrm{\&rho;}(\stackrel{\&OverBar;}{u_i^{\&prime;}{u}_k^{\&prime;}}\frac{{\&PartialD;u}_j}{{\&PartialD;x}_k}+\stackrel{\&OverBar;}{u_j^{\&prime;}{u}_k^{\&prime;}}\frac{{\&PartialD;u}_i}{{\&PartialD;x}_k})\\ {\mathrm{\&phi;}}_{\mathrm{ij},1}=-C_1\mathrm{\&rho;}\frac{\mathrm{\&epsiv;}}{k}(\stackrel{\&OverBar;}{u_i^{\&prime;}{u}_j^{\&prime;}}-\frac{2}{3}k{\mathrm{\&delta;}}_{\mathrm{ij}})\\ {\mathrm{\&phi;}}_{\mathrm{ij},2}=-C_2(P_{\mathrm{ij}}-\frac{2}{3}{P}_k{\mathrm{\&delta;}}_{\mathrm{ij}})\end{array}\right.$

Wherein, P is for producing item; φ _IjBe the ess-strain item; C ₁, C ₂Be coefficient, and C ₁=1.8, C ₂=0.6 draws corresponding physical model, and divides grid, and number of grid is not less than 5000;

In CFD software, carry out the single-phase flow numerical simulation then, determine the hydraulic performance of preliminary Antiplugging drip irrigation irrigator flow passage structure parameter runner,, promptly utilize numerical evaluation to obtain flow and pressure, according to q=kh if hydraulic performance can meet design requirement ^xReturn, the fluidised form index that obtains is about at 0.5～0.65 o'clock, then enters next step design;

Second step, carry out CFD solid, liquid two-phase flow numerical experiments, the particle random orbit model of selecting during simulation is:

$\left\{\begin{array}{c}\frac{{\mathrm{du}}_s}{\mathrm{dt}}=\frac{1}{{\mathrm{\&tau;}}_s}(\stackrel{\&OverBar;}{u}+u^{\&prime;}-u_s)\\ \frac{{\mathrm{dv}}_s}{\mathrm{dt}}=\frac{1}{{\mathrm{\&tau;}}_s}(\stackrel{\&OverBar;}{v}+v^{\&prime;}-v_s)\\ \frac{{\mathrm{dw}}_s}{\mathrm{dt}}=\frac{1}{{\mathrm{\&tau;}}_s}(\stackrel{\&OverBar;}{w}+w^{\&prime;}-w_s)+g-\frac{{\mathrm{\&rho;}}_{l}g}{{\mathrm{\&rho;}}_s}\end{array}\right.$

Wherein, u _s, v _s, w _sBe the component of three direction particle speeds, m/s; ρ _sBe particle density, kg/m ^-3ρ _lBe fluid density, kg/m ^-3U, v, w are respectively the component of the liquid mean flow rate of three directions, m/s; U ', v ', w ' are respectively the component of the liquid turbulence fluctuation velocity of three directions, m/s; T is time s;

Determine the regularity of distribution of solid particle in the runner then by numerical evaluation, and draw the isogram of solid particulate distributions;

In the 3rd step,, thereby redefine the flow passage structure parameter with 4% solid content isoline correction flow path boundary;

In the 4th step,, carry out the CFD numerical simulation according to second step, the 3rd step once more, till reaching designing requirement to the flow passage structure that redefines;

The 5th step, the douche runner of double optimization design is used the laser Rapid Manufacturing Technology be processed into high transparent test model, make up the visual test unit of particle rapidity imager, and utilize the visual test platform of particle rapidity imager to analyze the practical operation situation of solid particle and fluid, if the flow passage structure parameter in practical operation situation and the 3rd step is basic identical, then carry out next step, otherwise the correcting principle parameter is again since second step;

The visual test platform of described particle rapidity imager comprises tank (1) at least, submersible pump (2), and tensimeter (4), light source (5), test specimen model (6), high-speed camera (8) and computer (9), described tank (1) volume is 30L～50L; The lift of submersible pump (2) is 0.5m～12m, and flow is 1L/h～6L/h; Tensimeter (4) error is the 2cm water column; Light source (5) is the news lamp of 1500w; The material penetrability of test specimen model (6) is greater than 92%; The shooting speed of high-speed camera (8) is greater than 1000 frame/seconds;

Described tank (1), submersible pump (2), valve (3), tensimeter (4), test specimen model (6) links to each other successively with measuring cup (7), and light source (5) is positioned at test specimen model (6) top, high-speed camera (8) is positioned at test specimen model (6) below, and high-speed camera (8) links to each other with computer (9) simultaneously;

In the 6th step, according to the anti-blocking test standard in the world, carry out the muddy water verification experimental verification, and, obtain the flow passage structure of standardized Antiplugging drip irrigation irrigator according to the test findings approved product.

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