Patent Grant
10984149
The present application is a 371 U.S. National Stage of International Application No. PCT/CN2016/085231, filed Jun. 8, 2016, entitled “OPTIMIZATION DESIGN METHOD FOR SPATIAL FLOW PASSAGE OF LOW-PRESSURE EVEN SPRAY NOZZLE” which in turn claims priority to Chinese Application 201610103841.4 with the same title filed Feb. 25, 2016, both of which are incorporated herein by reference in its entirety.
The present invention relates to a structural optimization design method for a water-saving irrigation apparatus, particularly to an optimization design method for a spatial flow passage of a low-pressure even spray nozzle.
China is a great agricultural country with a large population, and is confronted with a severe water shortage problem. Therefore, promoting water-saving irrigation is crucial in the development of agricultural technology in China. The sprinkler irrigation technique is one of efficient water utilization techniques available at present. The irrigation quality of a sprinkler irrigation system depends on the hydraulic performance and operational performance of spray nozzles to a great extent, the spray nozzles are key devices for implementing sprinkler irrigation.
The flow passage of a spray nozzle accomplishes pressure water inflow, turning, energy exchange, and jetting. The structural form, physical dimensions, cross-sectional shape, and surface roughness, etc., of the flow passage have influence on the hydraulic performance of the spray nozzle. In order to reduce internal hydraulic loss in the flow passage of spray nozzle and realize optimization of hydraulic performance, for a small-size low-pressure spray nozzle, a water smashing mechanism is often mounted outside of the nozzle, or a special-shaped nozzle is used, or a tapered cut is worked out at the nozzle, etc., to improve atomization performance of the spray nozzle and increase the water volume near the spray nozzle, but the sprinkling range is often reduced to some extent.
Presently, the structural design in the research mainly focuses on design of auxiliary nozzle, multi-passage technique, water dispersion mechanism, and special-shaped nozzle, etc. However, an optimization design of parameters of spatial flow passage of the spray nozzle can improve hydraulic performance and operating stability of the spray nozzle. Though such an optimization design ought to be regarded as a key concern in the design process, there is few relevant research. In order to solve the above-mentioned problem, the present invention provides a design method for a spatial flow passage of a low-pressure even spray nozzle, so as to overcome the drawbacks of poor evenness and short sprinkling range of spray nozzles in the prior art; in addition, the design method is of far reaching importance for improving the design of flow passages of spray nozzles.
No relevant patent application is found in the patent search carried out by the inventor.
In order to overcome the above-mentioned defects or drawbacks of low-pressure spray nozzles in the prior art, the present invention provides an optimization design method for a spatial flow passage of a low-pressure even spray nozzle, so as to solve the problem of poor water sprinkling evenness of spray nozzles at a low pressure and increase sprinkling range.
In order to attain the object described above, the present invention employs the following technical solution:
An optimization design method for a spatial flow passage of a low-pressure even spray nozzle, comprising the following steps:
step 1: providing a low-pressure even spray nozzle to be optimized, which has an inlet with a circular cross section and a diameter D; and an outlet with cross-sectional area Sa; wherein, the contour of a flow passage between the cross section of the inlet and the cross section of the outlet is in an arc shape; the diameter D of the inlet and the cross-sectional area Sa of the outlet are a fixed value respectively;
step 2: establishing a three-dimensional coordinate system, in which a center of circle of the cross section of the inlet is taken as an origin, the vertical direction from the origin is taken as a Y-axis of the coordinate system, a center of circle of the flow passage contour is positioned in a X-axis of the coordinate system, and the tangent point between the flow passage contour and the Y-axis is right located at the origin of the coordinate system;
step 3: selecting variable parameters required for optimization of the spatial flow passage of the low-pressure even spray nozzle, including: deflection angle α of flow passage, arc radius r of flow passage contour, arc length L of flow passage contour, elevation angle γ of outlet, and cross-sectional shape of outlet; wherein, the deflection angle α of flow passage is defined as an included angle between a straight line passing through the center of circle of the cross section of the inlet and the centroid of the cross section of the outlet and the Y-axis; the arc length L of flow passage contour is defined as the length of arc flow passage from the center of circle of the cross section of the inlet to the centroid of the cross section of the outlet; and the elevation angle γ of outlet is defined as an intersection angle between the water flow jetted from the low-pressure even spray nozzle and a horizontal plane;
step 4: plotting a spatial flow passage with different variable parameters described in the step 3 with three-dimensional modeling software;
step 5: analyzing flow field characteristics of the spatial flow passage plotted in the step 4 with different variable parameters with a numerical simulation technique, and analyzing simulation results with an orthogonal test method, to obtain a cross-sectional shape of the outlet and corresponding variable parameters when the sprinkling performance of the low-pressure even spray nozzle is optimal under a condition that the diameter D of the inlet and the cross-sectional area Sa of the outlet are fixed values;
step 6: changing the fixed values of the diameter D of the inlet and the cross-sectional area Sa of the outlet and repeating the above steps, to obtain a number of sets of corresponding different variable parameters when the spatial flow passage of the low-pressure even spray nozzle is optimal on the basis of different sets of fixed values of the diameter D of the inlet and the cross-sectional area Sa of the outlet;
step 7: using a mathematical fitting method to fit the sets of corresponding variable parameters obtained in the step 6 when the spatial flow passage of the low-pressure even spray nozzle is optimal, so as to obtain an optimal structural design of the spatial flow passage of the low-pressure even spray nozzle finally.
Furthermore, after the cross-sectional shape of the outlet and corresponding variable parameters when the sprinkling performance of the low-pressure even sprinkler is optimal are obtained in the step 5, then the spatial flow passage of the low-pressure even spray nozzle is machined according to the cross-sectional shape of the outlet and the variable parameters, and the resultant spatial flow passage is verified by experimental verification, to further prove reliability of the cross-sectional shape of the outlet and corresponding variable parameters obtained in the step 5.
Furthermore, in the step 6, in view of product uniformity and machining difficulty, after the fixed values of the diameter D of the inlet and the cross-sectional area Sa of the outlet are changed, the cross-sectional shape of the outlet is no longer treated as a variable parameter, i.e., the cross-sectional shape of the outlet obtained when the sprinkling performance of the low-pressure even spray nozzle is optimal in the step 5 is kept.
Furthermore, in the step 4, when the contour of the spatial flow passage is plotted under different variable parameters, six different outlet shapes, i.e., shape A, shape B, shape C, shape D, shape E, and shape F, are selected for the cross-sectional shape of the outlet; the value range of the deflection angle α of flow passage is determined as 4°˜7°; the value range of the radius r of flow passage contour is determined as 22˜24 mm; the value range of the arc length L of flow passage contour is determined as 26˜30 mm; and the value range of the elevation angle γ of outlet is determined as 28°˜32°.
Furthermore, in the step 1, the initial value of the diameter D of the inlet is set to 5.6 mm; the initial value of the cross-sectional area Sa of the outlet is set to 19.5 mm2; when the spatial sprinkling performance of the low-pressure even spray nozzle is optimal the variable parameters obtained in the step 5 are: deflection angle α=5.5°, radius r of flow passage contour=23 mm, arc length L of flow passage contour=28 mm, elevation angle γ of outlet=30°; the cross-sectional shape of the outlet is shape A; the shape A consists of a first quadrant, a second quadrant, a third quadrant, and a fourth quadrant, and the area S1 in the first quadrant is 4.1 mm2, the area S2 in the second quadrant is 5.5 mm2, the area S3 in the third quadrant is 4.9 mm2, and the area S4 in the fourth quadrant is 5.0 mm2.
Furthermore, in the step 6, the diameter D of the inlet is set to 4.8 mm, 5.2 mm, 6.0 mm, and 6.4 mm respectively, and the corresponding cross-sectional area Sa of the outlet is set to 16.7 mm2, 18.1 m2, 20.9 m2, and 22.3 m2 respectively; the cross-section shape of the outlet is shape A, and then in the case of the diameter of the inlet is 4.8 mm, the optimal structural parameters of the spatial flow passage are: the deflection angle α of the flow passage in the circumferential direction is 5.2°, the radius r of the flow passage contour is 22 mm, the arc length L is 25.5 mm, the elevation angle γ of the outlet is 28°, the area S1 in the first quadrant is 3.5 mm2, the area S2 in the second quadrant is 4.7 mm2, the area S3 in the third quadrant is 4.2 mm2, and the area S4 in the fourth quadrant is 4.3 mm2; in the case of the diameter of the inlet is 5.2 mm, the optimal structural parameters of the spatial flow passage are: the deflection angle α of flow passage in the circumferential direction is 5.4°, the radius r of flow passage contour is 22.5 mm, the arc length L is 27 mm, the elevation angle γ of outlet is 32°, the area S1 in the first quadrant is 3.8 mm2, the area S2 in the second quadrant is 5.1 mm2, the area S3 in the third quadrant is 4.6 mm2, and the area S4 in the fourth quadrant is 4.6 mm2; in the case of the diameter of the inlet is 6.0 mm, the optimal structural parameters of the spatial flow passage are: the deflection angle α of flow passage in the circumferential direction is 5.6°, the radius r of flow passage contour is 23.5 mm, the arc length L is 28.5 mm, the elevation angle γ of outlet is 30°, the area S1 in the first quadrant is 4.3 mm2, the area S2 in the second quadrant is 5.9 mm2, the area S3 in the third quadrant is 5.3 mm2, and the area S4 in the fourth quadrant is 5.4 mm2; in the case of the diameter of the inlet is 6.4 mm, the optimal structural parameters of the spatial flow passage are: the deflection angle α of flow passage in the circumferential direction is 5.8°, the radius r of flow passage contour is 24 mm, the arc length L is 28.5 mm, the elevation angle γ of outlet is 28°, the area S1 in the first quadrant is 4.6 mm2, the area S2 in the second quadrant is 6.3 mm2, the area S3 in the third quadrant is 5.7 mm2, and the area S4 in the fourth quadrant is 5.7 mm2.
Furthermore, the optimal structural design of the spatial flow passage of the spray nozzle obtained in the step 7 meets the following criterion:
The cross-sectional shape of the outlet is shape A; the area S1 in the first quadrant of the cross section of the outlet, the area S2 in the second quadrant, the area S3 in the third quadrant, and the area S4 in the fourth quadrant meet:
Wherein, D is the diameter of the inlet, in unit of mm, D0 is an initial value set for the diameter D of inlet in the step 1, and D0=5.6 mm; α is the deflection angle of the flow passage, in unit of degree (°); Sa is the cross-sectional area of the outlet, in unit of mm2, and Sa0 is an initial value set for the cross-sectional area Sa of outlet in the step 1, and Sa0=19.5 mm2.
Technical Benefits of the present invention: A novel spatial flow passage of low-pressure even spray nozzle is designed and optimized, and thereby the hydraulic performance of the spray nozzle is optimized, and the spray nozzle is efficient and energy-saving.
In the figures: 1—area S1 in the first quadrant; 2—area S2 in the second quadrant; 3—area S3 in the third quadrant; 4—area S4 in the fourth quadrant
The technical concept of the present invention is to change the structural parameters of the spatial flow passage of a spray nozzle and thereby attain a purpose of optimizing hydraulic performance of the spray nozzle operating under a low pressure condition. Hereunder the technical solution in the present invention will be further detailed with reference to
The novel optimization design method for a spatial flow passage of a low-pressure even spray nozzle provided in this embodiment mainly comprises:
Step 1: Determining the Model of a Spray Nozzle
The model of a spray nozzle is mainly determined by the diameter of inlet. Here, the diameter D of inlet of the spray nozzle is set to 5.6 mm according to the requirement in this embodiment. The cross-sectional area of the outlet of the spray nozzle is an important factor that has direct influence on the evenness of sprinkler irrigation. The cross-sectional area S of the outlet of this spray nozzle model is 19.5 mm2. Six different outlet shapes are plotted, including 3 irregular shapes and 3 regular shapes (shown in
Step 2: a three-dimensional coordinate system is established, in which a center of circle of the cross section of the inlet is taken as an origin, the vertical direction from the origin is taken as a Y-axis of the coordinate system, a center of circle of the flow passage contour is positioned in a X-axis of the coordinate system, and the tangent point between the flow passage contour and the Y-axis is right located at the origin of the coordinate system;
Step 3: variable parameters required for optimization of the spatial flow passage of the low-pressure even spray nozzle are selected, including: deflection angle α of flow passage, arc radius r of flow passage contour, arc length L of flow passage contour, elevation angle γ of outlet, and cross-sectional shape of outlet (in this embodiment, six different cross-sectional shapes are selected); wherein, the deflection angle α of flow passage is defined as an included angle between a straight line formed by passing through the center of circle of the cross section of the inlet and the centroid of the cross section of the outlet and the Y-axis; the arc length L of flow passage contour is defined as the length of arc flow passage from the center of circle of the cross section of the inlet to the centroid of the cross section of the outlet; and the elevation angle γ of outlet is defined as an intersection angle between the water flow jetted from the low-pressure even spray nozzle and a horizontal plane; the selection is made on the following bases: in view that the water flow generates a rotational driving moment against the internal wall surface of the flow passage and drives the spray nozzle to rotate owing to the existence of a deflection angle α of flow passage, the deflection angle α of flow passage is taken as an important parameter for evaluating operating stability of the spray nozzle; the arc radius r and arc length L are also important factors that have great influence on the direction of water flow jetted from the spray nozzle as well as the jet flow speed at the outlet; the elevation angle γ of outlet has influence on the sprinkling range of the spray nozzle by affecting the direction of the jet flow from the outlet.
Step 4: Based on the design experience on spatial flow passages of low-pressure even spray nozzles, the value range of the deflection angle α of flow passage is usually 4°˜7°. The value range of the radius r of flow passage contour is determined as 22˜24 mm. In order to allow the movement of the water flow in the flow passage to develop fully, the arc length L of flow passage contour is increased slightly on the basis of the dimension determined in the empirical design, and is set to 26˜30 mm. The value range of the elevation angle γ of outlet is set to 28°˜32°, which can ensure a maximum sprinkling range of the spray nozzle.
Step 5: Three-dimensional structural diagrams of spatial flow passage are plotted according to empirical design values of the parameters described in the step 4 and the six different given cross-sectional shapes; thus, combinations of different structural parameters of the spray nozzle shown in Table 1 are obtained; then, schematic structural diagrams of the flow passage are plotted with three-dimensional modeling software.
Step 6: Preselecting Optimization Solution
Numerical simulation and calculation is carried out for the different spatial flow passages plotted according to the Table 1, and the simulation results are analyzed with an orthogonal test method, to obtain a preselected optimization solution: the deflection angle α of flow passage in the circumferential direction is 5.5°, the radius r of flow passage contour is 23 mm, the arc length L is 28 mm, the elevation angle γ of outlet is 30°; an optimal structural shape of the cross section of the outlet is a shape A as shown in
Step 7: Experimental Verification
Spatial flow passages obtained with a number of typical parametric combinations are machined and tested, to verify accuracy of simulation. The results are in line with the results obtained in numerical simulation, i.e., the optimal structural dimensions are: the deflection angle α of flow passage in the circumferential direction is 5.5°, the radius r of flow passage contour is 23 mm, the arc length L is 28 mm, and the elevation angle γ of outlet is 30°; the cross-sectional shape of the outlet is the shape A as shown in
Step 8: Values of diameter D of outlets of different models of spray nozzles are selected, i.e., 4.8 mm, 5.2 mm, 6.0 mm, and 6.4 mm, and corresponding values of cross-sectional area Sa of outlet are selected respectively, i.e., 16.7 mm2, 18.1 mm2, 20.9 mm2, and 22.3 mm2; in view of product uniformity and machining difficulty, the cross-sectional area of outlet is no longer treated as a variable parameter in this step, i.e., the shape A is still employed; the above-mentioned steps are repeated, to determine optimal combinations of structural parameters of spatial flow passages of different spray nozzle models. In the case of the diameter of the inlet is 4.8 mm, the optimal structural parameters of the spatial flow passage are: the deflection angle α of flow passage in the circumferential direction is 5.2°, the radius r of flow passage contour is 22 mm, the arc length L is 25.5 mm, the elevation angle γ of outlet is 28°, the area S1 in the first quadrant is 3.5 mm2, the area S2 in the second quadrant is 4.7 mm2, the area S3 in the third quadrant is 4.2 mm2, and the area S4 in the fourth quadrant is 4.3 mm2. In the case of the diameter of the inlet is 5.2 mm, the optimal structural parameters of the spatial flow passage are: the deflection angle α of flow passage in the circumferential direction is 5.4°, the radius r of flow passage contour is 22.5 mm, the arc length L is 27 mm, the elevation angle γ of outlet is 32°, the area S1 in the first quadrant is 3.8 mm2, the area S2 in the second quadrant is 5.1 mm2, the area S3 in the third quadrant is 4.6 mm2, and the area S4 in the fourth quadrant is 4.6 mm2; in the case of the diameter of the inlet is 6.0 mm, the optimal structural parameters of the spatial flow passage are: the deflection angle α of flow passage in the circumferential direction is 5.6°, the radius r of flow passage contour is 23.5 mm, the arc length L is 28.5 mm, the elevation angle γ of outlet is 30°, the area S1 in the first quadrant is 4.3 mm2, the area S2 in the second quadrant is 5.9 mm2, the area S3 in the third quadrant is 5.3 mm2, and the area S4 in the fourth quadrant is 5.4 mm2. In the case of the diameter of the inlet is 6.4 mm, the optimal structural parameters of the spatial flow passage are: the deflection angle α of flow passage in the circumferential direction is 5.8°, the radius r of flow passage contour is 24 mm, the arc length L is 28.5 mm, the elevation angle γ of outlet is 28°, the area S1 in the first quadrant is 4.6 mm2, the area S2 in the second quadrant is 6.3 mm2, the area S3 in the third quadrant is 5.7 mm2, and the area S4 in the fourth quadrant is 5.7 mm2. By means of data fitting, finally optimal design parameters of the spatial flow passage of spray nozzle are obtained, which shall meet:
Wherein, D is the diameter of the inlet, in unit of mm, D0 is an initial value set for the diameter D of inlet in the step 1, and D0=5.6 mm; α is the deflection angle of the flow passage, in unit of degree (°); Sa is the cross-sectional area of the outlet, in unit of mm2, and Sa0 is an initial value set for the cross-sectional area Sa of outlet in the step 1, and Sa0=19.5 mm2.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201610103841.4 | Feb 2016 | CN | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CN2016/085231 | 6/8/2016 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2017/143694 | 8/31/2017 | WO | A |
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| 20080004846 | Onozuka | Jan 2008 | A1 |
| 20110077925 | Vander Griend | Mar 2011 | A1 |
| 20130246011 | Nikolayev | Sep 2013 | A1 |
| 20140200837 | Blair | Jul 2014 | A1 |
| 20140367499 | Odenthal | Dec 2014 | A1 |
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| 101799841 | Aug 2010 | CN |
| 103962257 | Aug 2014 | CN |
| 104268313 | Jan 2015 | CN |
| 105160096 | Dec 2015 | CN |
| 2009073226 | Jun 2009 | WO |
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| International Search Report for International Application PCT/CN2016/085231, dated Nov. 14, 2016, four (4) pages. |
| Number | Date | Country | |
|---|---|---|---|
| 20190251229 A1 | Aug 2019 | US |
