KR102399733B1 - Drone nozzle for agriculture - Google Patents

Abstract

The present invention relates to an agricultural drone nozzle, and more specifically, in spraying water and pesticides in the air using a drone, in order to improve the effective spray width, droplet size and spray uniformity, An inlet 110 is provided, a spray outlet 130 is provided on the other side, and an air channel 111 having a reduced cross-sectional area in the direction from the air inlet 110 to the spray outlet 130 is formed, and the air channel 111 is formed. a nozzle body in which a nozzle part 120 is formed from the end of the spray outlet 130; a feedback channel 140 interconnecting the nozzle part inlet 121 and the nozzle part outlet 122 and disposed in parallel with the nozzle part 120; a water inlet 150 connected to the nozzle outlet 122; It relates to an agricultural drone nozzle comprising a.

Description

Drone nozzle for agriculture

FIELD OF THE INVENTION The present invention relates to drone nozzles for agriculture, and more particularly to drone nozzles for agricultural use with a feedback channel, mounted on a drone for effectively spraying water and pesticides on crops in the air.

In general, a drone is an unmanned aerial vehicle that can be controlled by radio waves, and is equipped with a camera, sensor, and communication system. varied up to

Although early drones were developed for military purposes and to support search and rescue operations, since then drones have been developed for a variety of civilian purposes, such as transportation and fire suppression. An aerodynamic analysis method to improve durability by maintaining

Recently, aerial spray technology using drones is being used. This method reduces labor costs and at the same time eliminates the risk of physical damage to crops and soil caused by wheels or tracks of machines. are receiving

The spray performance of agricultural drones can be evaluated through various factors such as effective spray width, spray uniformity, droplet size, spray droplet adhesion rate, and scattering characteristics. However, existing research on agricultural drones mainly focuses on improving the spray direction or range are aligning

As an example, in the Republic of Korea Patent Registration No. 10-2155527 (Patent Document 1), a drone body equipped with a rotary blade and a chemical liquid container; A spray nozzle that is mounted on the drone body from a lower portion than the rotor blade, receives the chemical solution from the chemical solution container and sprays it downwardly; the injection nozzle is made to include, but the jet nozzle is the flight direction of the drone body with respect to the drone body There have been proposed agricultural drones that are disposed obliquely to the spray nozzle so that the chemical liquid sprayed from the injection nozzle is sprayed obliquely with respect to the drone body in the flight direction of the drone body. However, it does not suggest spray width, spray uniformity, droplet size, spray droplet adhesion rate, scattering characteristics, etc. that can evaluate the spray performance of drones.

1. Korean Patent Registration No. 10-2155527 Patent Publication

1. Foundation of Agri. Tech. Commercialization & Transfer, "Comprehensive test of agricultural unmanned aerial spreader", 22 (2016) 2. LEE, Sang. Woo, "Study on the Structures of the Nozzle for the Spray", Korean Society for Agricultural Machinery, Vol. 18, No. 2, 100-109, 22 (1993).

The present invention is to solve the problems inherent in the prior art, and in spraying water and pesticides in the air using a drone, an agricultural drone nozzle that can improve effective spray width, droplet size and spray uniformity The purpose is to provide

In the agricultural drone nozzle of the present invention for achieving the above object, an air inlet is provided on one side, a spray outlet is provided on the other side, and an air flow path with a reduced cross-sectional area in the direction of the spray outlet from the air inlet is formed, and the air flow path a nozzle body formed with a nozzle part from the end of the to the spray outlet; a feedback channel interconnecting the nozzle inlet and the nozzle outlet and formed in parallel with the nozzle; a water inlet connected to the nozzle outlet; It is characterized in that it includes.

As a preferred embodiment, the cross-sectional area of the spray outlet may be gradually expanded in the air outlet direction.

As a more preferred embodiment, a pair of the feedback channels may be disposed symmetrically with the nozzle unit interposed therebetween.

Accordingly, when the fluid is supplied to the nozzle unit and the feedback channel connected in parallel with the nozzle unit, a Coanda effect occurs in which an airflow ejected close to the wall of the feedback chamber is attached to the wall. This creates a cross flow through the feedback flow path inside the nozzle, causing the fluid to vibrate at the outlet.

Agricultural drone nozzles with a feedback channel as in the present invention generate a vibrating jet flow through the interaction between the nozzle unit and the feedback channel without additional external equipment, and this vibration can generate a uniform spray compared to conventional nozzles.

In addition, agricultural drone nozzles with feedback channels have a droplet size that is reduced by at least 6 to 8 times, making them suitable for use as sprays and have improved spraying uniformity than commercial nozzles.

Besides, agricultural drone nozzle with feedback channel can reduce the consumption of water and pesticide in addition to spray performance including droplet size and uniformity, so that the agricultural drone nozzle of the present invention can not only improve spray performance but also agricultural field It has effects such as contributing to the expansion of the drone market of

1 is a front view of an agricultural drone nozzle according to an embodiment of the present invention.
Figure 2 is a cross-sectional view taken along line AA of Figure 1;
Figure 3 is a cross-sectional view taken along line BB of Figure 2;
Figure 4 is an experimental design of the agricultural drone nozzle according to an embodiment of the present invention.
5 is a set of experimental equipment for measuring spray performance of agricultural drone nozzles.
6 is a diagram showing changes in flow rate and pressure according to various loads.
7 is a diagram sequentially showing an image processing procedure.
Fig. 8 is representative images from positions 1 and 2 of Fig. 5 for various loads.
9 is a diagram showing the spray area contour according to load change for commercial nozzles and feedback nozzles.
FIG. 10 is a plot of the spray area measured as a function of load change at position 1 in FIG. 5 for a feedback nozzle; FIG.
11 is a line profile showing the nozzle injection amount in the z-axis 5.
12 is a graph comparing the average particle size distribution and total droplet diameter along the radial direction for a commercial nozzle and a feedback nozzle according to a load change.
13 is a diagram showing the change in spraying amount according to the radial position (a) and the corresponding FWHM (b).
14 is a diagram showing the normalized standard deviation of the spray volume at various radial positions.
15 is a graph comparing the average particle size distribution along the radial direction (a) and the total droplet diameter of the non-feedback nozzle (b).
16 is a diagram showing the change of injection amount according to the radial position (a) and the corresponding FWHM (b) for the non-feedback nozzle.

Since the present invention can have various modifications and can have various embodiments, preferred embodiments of the present invention will be exemplified below, and the present invention will be described in detail based thereon. However, this is not intended to limit the present invention to only the illustrated embodiments, and the spirit and scope of the present invention includes ordinary modifications or equivalents to substitutes of the illustrated forms.

In addition, throughout the specification, that a part is 'connected' to another part includes a case in which it is 'directly connected' or 'indirectly connected' with an element, and 'includes' a certain element is specifically opposed. Unless otherwise stated, it means that other components may be added, rather than excluding other components.

1 is a front view of an agricultural drone nozzle according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line A-A of FIG. 1, and FIG. 3 is a cross-sectional view taken along line B-B of FIG.

1 to 3, the agricultural drone nozzle of the present invention is mounted on a drone to spray water and pesticides together with air in the air, and includes a nozzle body 100 mounted on the drone.

An air inlet 110 through which air is introduced at a predetermined pressure is provided on one side of the nozzle body 100 , and a spray outlet 130 is provided on the other side of the nozzle body 100 , while the air inlet 110 is An air passage 111 having a reduced cross-sectional area is formed in the spray outlet 130 direction, and a nozzle unit 120 is formed from an end of the air passage 111 to the spray outlet 130 .

A feedback channel 140 installed in parallel with the nozzle part 120 is provided inside the nozzle body 100, and one end of the feedback channel 140 is connected to the nozzle part inlet 121 and the feedback channel ( The other end of 140 is connected to the nozzle outlet 122 .

The water inlet 150 for injecting water into the nozzle body 100 is connected to the nozzle part outlet 122 .

At this time, the spray outlet 130 has a predetermined length, and its cross-sectional area may be gradually expanded in the air discharge direction.

In addition, a pair of the feedback channels 140 may be disposed symmetrically with the nozzle unit 120 interposed therebetween.

Hereinafter, the spray performance test of the agricultural drone nozzle according to the present invention will be described in detail, and the present invention will be further embodied through this.

1. Experimental method

- Spraying performance

The spraying performance of agricultural drones is evaluated using parameters such as spray uniformity, droplet size and velocity, adhesion rate of spray particles, and scattering properties, the parameters chosen may vary depending on the target and the rater. The Korean government is using spray uniformity as a standard for agricultural drone certification (see Non-Patent Document 1).

Accordingly, the spraying performance of the agricultural drone nozzle of the present invention and the conventional drone type was compared based on the spray uniformity and droplet size. These parameters can evaluate the unique effect of nozzle design on spray performance without the influence of external factors such as wind and temperature.

FWHM (full width at half maximum), which will be described later, is a value indicating the width of a curve between points at half the maximum value and is used to indicate the size of a function for distribution. The present inventors calculated the spray width using the FWHM, and compared the spraying uniformity in terms of the spray amount and droplet size according to the radial position.

- Experimental nozzle

The injection performance of the drone nozzle of the present invention was compared with that of the other two nozzles.

First, the agricultural drone nozzle according to the present invention was designed as shown in FIG. 4 and manufactured by 3D printing technique (hereinafter referred to as 'feedback nozzle'). The dimensions of the main part are, the diameter of the air inlet 110 is 8 mm, the diameter of the water inlet 150 is 1 mm, the air passage 111, the width of each of the nozzle unit 120 and the spray outlet 130 is 2 mm, the air passage 111 ) was reduced from 10mm to 3.2mm in height, and the spray outlet 130 was extended from 3.2mm to 10mm.

As a comparative material, one is a fan-shaped commercial nozzle (TEEJET XR11002, spray system) (hereinafter referred to as 'commercial nozzle'), which is currently used in commercial and agricultural drones, and the other is to check the feedback channel effect of the feedback nozzle. It is a nozzle without a feedback channel (hereinafter abbreviated as 'non-feedback nozzle'). The dimensions of the non-feedback nozzle are the same as those of the feedback nozzle of FIG. 4 except for the feedback channel. The flow rate for the nozzle test was set to 500mL/min, which is similar to the conditions actually used in agricultural drones.

- Measurement of injection performance

5 schematically shows the experimental setup structure used to measure the injection performance, and the amount of oil was injected using an air pump (Wob-L Piston Gas Pump WA80DC, YLKTECH), and the water supply through the water inlet is through hydrostatic pressure. Controlled. After generating an oil flow of 8.1L/min at the inlet using an air pump, hydrostatic pressure was applied to spray. To change the hydrostatic pressure, a weight was added to the upper part of the water piston and the weight was changed from 0 kg to 50 kg in 10 kg increments to check the injection performance. The static pressure was measured at positions 1 to 4 shown in FIG. 5 , and the pressure and flow rate corresponding to various loads of the water piston are illustrated in FIG. 6 . In the case of no load, the pressure and flow rate were 0.05 bar and 50 mL/min, and the pressure and flow rate were found to increase with increasing load. The rate of change was found to increase more at a load greater than 30 kg, and when the load exceeds 30 kg, both pressure and flow increase as the load increases.

Images of the spray particles were captured at 2000 frames per second with a high-speed camera (Fastcam Mini UX50, Photron, USA). The obtained images were analyzed using digital image processing techniques, the origin was set at the center of the nozzle exit in the analysis, and the x-axis and z-axis in Fig. 5 represent the radial and jetting directions, respectively.

As shown in FIG. 5 , spray droplets were visualized in four areas to confirm the particle distribution in a wide range, and the camera was moved ±50 mm in the x-axis and 50 mm in the z-axis to take pictures.

- Data analysis

7 shows an image processing procedure, (a) is the original image, (b) is threshold correction, (c) is noise reduction, (d) is particle tracking.

The processed images were obtained by sequentially performing threshold correction and noise reduction on the original image using Image J software, and the particle tracking function of Image J software was used to extract the spray droplet information including position and size. Used with images.

FIG. 8 shows representative processed images of the feedback nozzles obtained at positions 1 and 2 of FIG. 5 , wherein (a) of FIG. 8 is obtained at position 1, (b) is obtained at position 2.

For statistical analysis, spray images were captured for 1 second, final droplet information was summed and averaged, and various parameters such as FWHM for radial position and droplet distribution were calculated from the droplet information to compare spray performance.

2. Results

- Spray distribution

9 is a comparison of the outline of each spray distribution of the commercial nozzle and the feedback nozzle, (a) of FIG. 9 is a commercial nozzle, (b) to (e) are 0kg, 30kg, 40kg, respectively, the load in the feedback nozzle, Indicates the state in which 50 kg is applied.

10 is to more clearly compare the outline of the spray area through the spray distribution of the feedback nozzle at position 1 of FIG. , indicates the state in which 40 kg and 50 kg are applied.

In all cases, a large amount of water droplets were ejected along the center line of the nozzle, and the amount of water droplets decreased as the distance from the nozzle tip increased.

In addition, for quantitative comparison, the line profile of the injection amount for each load when z = 5 is shown in FIG. 11 . The injection width increases as the load increases, as shown in FIG. 10 . The jetted water is concentrated near the nozzle tip, but the feedback nozzle has an intrinsic value further away from the nozzle tip. As the load increased, both the spray volume and the effective spray angle increased, meaning that it was easier to produce a uniform spray when a higher load was applied from the feedback nozzle.

- droplet size

Fig. 12 (a) shows the average particle size distribution along the radial direction for a commercial nozzle and a feedback nozzle to which various loads are applied, and (b) is a comparison of the total droplet diameter. The left and right axes are for feedback nozzles and commercial nozzles, respectively.

As for the average droplet size distribution at the radial position from the nozzle center, a larger droplet is observed at the nozzle center in all cases as shown in Fig. 12(a). Compared with the feedback nozzle, the commercial nozzle showed a sharp peak distribution, and the droplet size of the commercial nozzle decreased from x/D = 1.5 to 10%. The feedback nozzle had a much smaller droplet size than the commercial nozzle and gradually decreased in size as the radial position increased, and this distribution shows that the feedback nozzle can produce a more uniform droplet size over a wider range than the commercial nozzle.

Figure 12 (b) shows the average droplet size in all positions, and according to "Study on the Structure of Nozzle for Sprayer" of Non-Patent Document 2, the diameter of the spray particles is 150 ~ 440㎛, and When the optimum diameter is 250 ~ 500㎛, good spray effect can be obtained.

Commercial nozzles have a droplet size of 1.70 mm, which exceeds the range suitable for sprayers, while feedback nozzles have a drop size of 226 μm at 30 kg load conditions suitable for agricultural applications. Under the load conditions of 40 kg and 50 kg, the diameters of the droplets are 265 μm and 280 μm, respectively, which is sufficient to prevent scattering. The reduction in droplet size indicates that feedback nozzles can improve the performance of agricultural drones.

- Spray uniformity

13 (a) shows the average droplet size distribution along the radial direction, and (b) compares the total droplet diameters of the non-feedback nozzle and the feedback nozzle.

In (a) of FIG. 13 , the spray amount was obtained by summing the area of the particles at all z positions having the same radial position. The maximum amount of unloaded commercial nozzles and feedback nozzles is about 30470 mm 2 and 1784 mm 2 respectively. The amount of spray increases according to the load and reaches 28705mm2 under the 50kg load condition. Fig. 13(b) shows that the FWHM (0.233D) of the commercial nozzle is much smaller than that of the feedback nozzle even without the load condition (1.017D). At a load of 30 kg or more, the FWHM is similar regardless of the load condition.

Considering that uniform spray is a key parameter for effective spraying and extending the flight time of drones, the FWHM result shows that the feedback nozzle is superior in terms of spray uniformity despite the large amount of spraying of commercial nozzles. In addition, feedback nozzles can reduce pesticide usage compared to commercial nozzles.

14 shows the standard deviation for the injection amount at various radial positions normalized to the average value of the total injection amount. All graphs show a similar trend in which the standard deviation decreases along the radial direction from the center of the graph to x/D = ± 1.5. The standard deviation of the developed nozzle increases with the applied load, and the maximum standard deviation of a commercial nozzle with a load of 50 kg and a feedback nozzle is about 17 and 11.5, respectively, confirming that the distribution of the feedback nozzles is more uniform.

- Effects of feedback channels

To check the effectiveness of the feedback channel, an experiment was performed on a non-feedback nozzle with a setting similar to that of the feedback nozzle. The no-load test was excluded due to insufficient injection amount as observed in the feedback nozzle test. Fig. 15 (a) shows the change in droplet size according to the radial position and average droplet diameter of the non-feedback nozzle. The size change is similar to that of the feedback nozzle, a larger droplet is observed at the nozzle center, and the radial distance is It decreases in size as it increases. As shown in (b) of FIG. 15 , the diameters in all cases exceeded the appropriate range, and this result shows that the feedback channel is effective in generating droplets of an appropriate size and a uniform spray.

Fig. 16 shows the injection amount according to the radial position and the FWHM for the non-feedback nozzle. That is, (a) of FIG. 16 shows the change in the injection amount according to the radial position, and (b) shows the corresponding FWHM for the non-feedback nozzle. Similar to the feedback scenario, the injection amount increases at a higher load, and the maximum amount is 20036.8㎟ at 50kg load. The FWHM was 1.329 at 30 kg, 1.375 at 40 kg, and 1.375 at 50 kg, which showed that the non-feedback nozzle showed less injection amount and FWHM value than the feedback nozzle, confirming that the feedback channel is more effective for uniform injection.

In order to further confirm the effect of the feedback channel, the jetting performance of the nozzle without the feedback channel was further reviewed. The diameter of the non-feedback nozzle was smaller than that of the commercial nozzle, but the droplet size increased as the feedback channel was removed regardless of the load condition. The droplet diameter of the non-feedback nozzle was not suitable for use in the nebulizer. In addition, the spray uniformity of the non-feedback nozzle was lower than that with feedback, and when both droplet size and spray uniformity were considered, the FWHM was almost independent of the load exceeding 30 kg, whereas the droplet size increased as the load increased. , therefore, it was confirmed that the 30 kg load condition was optimal. In addition, in addition to spray performance including droplet size and uniformity, feedback nozzles can reduce water and pesticide consumption, for example, when a 50 kg load is applied, the feedback nozzle's flow rate is 150 mL/min, which is equivalent to that of commercial nozzles (500 mL/min). min), which means that the consumption of water and pesticides can be significantly reduced.

On the other hand, the same experiment was performed on the feedback nozzle smaller than the standard of the feedback nozzle illustrated in FIG. 4 , and as a result, an effect similar to the above experiment result was obtained up to a nozzle range that was 33% smaller than the standard nozzle of FIG. It was confirmed that appeared, therefore, the agricultural drone nozzle of the present invention is not limited to the standard illustrated in FIG.

As such, the above description has been described according to limited embodiments showing the technical spirit of the present invention, but the present invention is not limited to specific embodiments or shapes and figures, and by changing, mixing, etc., some of the components of the embodiments. Various modifications and variations can be made by those of ordinary skill in the art to which the invention pertains without departing from the gist of the invention, and such modifications and variations are not to be individually understood from the technical spirit or prospect of the present invention. it won't be

100... nozzle body
110... air inlet
111... Air Euro
120... Nozzle
121... Nozzle inlet
122... Nozzle part outlet
130... spray outlet
140... Feedback Channel
150... water inlet

Claims (3)

a nozzle body having an air inlet on one side and a spray outlet on the other side, an air passage having a reduced cross-sectional area in a direction from the air inlet to the spray outlet, and a nozzle unit formed from an end of the air passage to the spray outlet;
a feedback channel interconnecting the nozzle inlet and the nozzle outlet and disposed in parallel with the nozzle;
a water inlet connected to the nozzle outlet; As an agricultural drone nozzle comprising a,
The cross-sectional area of the spray outlet gradually expands in the air discharge direction,
A pair of the feedback channels are disposed symmetrically with each other with the nozzle unit interposed therebetween,
The agricultural drone nozzle is, the diameter of the air inlet is 8mm, the diameter of the water inlet is 1mm, each width of the air passage, the nozzle part and the spray outlet is 2mm, the height of the air passage is reduced from 10mm to 3.2mm, and the spray Agricultural drone nozzle, characterized in that the outlet is extended from 3.2mm to 10mm. delete delete

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