Device Substantiation for Generating Artificial Rain Drops by Pneumohydraulic Liquid Spraying

The authors studied the pneumohydraulic device indicators for spraying liquids for irrigation, nutrition and protection of agricultural plants, taking into account the principles of water and energy conservation, based on preliminary gas saturation of sprayed water and the use of a cavitation effect in the design of the aerator unit during ejection and supply of air under pressure. (Research purpose) To determine the technological parameters of a pneumohydraulic device for spraying liquids to obtain controlled dispersive artificial rain and substantiate the choice of its optimal technical parameters depending on the operating modes. (Materials and methods) The authors used an algorithm for calculating parameters in EXCEL or WPS spreadsheet processor and mathematical expressions. (Results and discussion) The authors theoretically determined the minimum and maximum calculated parameters of the constructive solution geometry for spraying the liquid phase: water nozzle, air nozzle channel, mixing cell, middle annular gap, outlet nozzle. They changed indicators of operating water pressure – 0.20; 0.25; 0.30 and 0.35 megapascals; air – 0.25 and 0.30 megapascals, provided the water flow rate from 0.002 to 0.010 liter per second and air – from 0.0005 to 0.0090 kilogram per second. With an increase in the water flow rate within the specified limits and the ejection coefficient from 0.5 to 0.9, a linear increase in the average annular gap diameter from 2 to 15 millimetres was revealed, as well as a nonlinear dependence of the increase in the sprayer mixing cell diameter from 5 to 20 millimetres. The authors showed the possibility of reducing the mixing cell diameter if the water pressure was increased from 0.25 to 0.35 megapascal's and the air pressure was from 0.20 to 0.30 megapascals. They obtained the parameters values for the designed and experimental samples development, which turned out to be significantly less than when operating in the air ejection mode: the outlet nozzle and the middle annular gap – by 16 percent, the air nozzle – by 23, the diameter of the mixing cell – by 50 percent or more. (Conclusions) The authors obtained calculated data to optimize technological parameters and design solutions, which would speed up the manufacture of designed and model samples of the device and its experimental testing for the generation of dispersive artificial rain drops.

A Quantitative Analysis of Point Clouds from Automotive Lidars Exposed to Artificial Rain and Fog

Light Detection And Ranging sensors (lidar) are key to autonomous driving, but their data is severely impacted by weather events (rain, fog, snow). To increase the safety and availability of self-driving vehicles, the analysis of the phenomena of the consequences at stake is necessary. This paper presents experiments performed in a climatic chamber with lidars of different technologies (spinning, Risley prisms, micro-motion and MEMS) that are compared in various artificial rain and fog conditions. A specific target with calibrated reflectance is used to make a first quantitative analysis. We observe different results depending on the sensors, and unexpected behaviors in the analysis with artificial rain are seen where higher rain rates do not necessarily mean higher degradations on lidar data.

Swinging-Pulse Sprinkling Head for Rain Simulators

Rainfall simulators are research devices that can be used for studying runoff and sediment transport on the plot scale. This technical note introduces a new solution that combines the two most commonly used methods for generating artificial rain—swinging and pulse jet systems. Reasons for developing this device are its universal use, simple construction, and reduction of water consumption, with better spatial distribution of rain and rainfall kinetic energy close to that of natural conditions. Routine operations of this device are expected for plots of 1 × 1 m, with a height 2–2.5 m. The rained surface could be extended to 2 × 2 m with lower spatial distribution. The sprinkled area in this case was limited by the drain box that also collected the remaining water. The principle of the presented single-nozzle simulator can be extended to multi-nozzle simulators for larger experimental plots.

Experimental Investigation on Influence of Shed Parameters on Surface Rainwater Characteristics of Large-Diameter Composite Post Insulators under Rain Conditions

The discharges of water columns and droplets between the sheds make the leakage distance not effectively used, which is one of the main reasons for flashover of composite post insulators under heavy rainfall. To study the influence of shed parameters on surface rainwater characteristics, artificial rain tests were carried out on the large-diameter composite post insulators under the rainfall intensity of 2–15 mm/min. Lwc (the length of water columns at the edge of large sheds), Nwc (the number of water columns at the edge of large sheds), Nwde (the number of water droplets at the edge of large sheds) and Nwds (the number of water droplets in the space between two adjacent large sheds) were proposed as the parameters of surface rainwater characteristics. The influences of large shed spacing, large shed overhang and rod diameter on the parameters of surface rainwater characteristics under different rainfall intensities were analyzed. The experimental results show that, under the same rainfall intensity, with the rise in large shed spacing, large shed overhang or rod diameter, Lwc, Nwc, Nwde and Nwds all increase. Under different rainfall intensities, the trends of the parameters with the change in shed parameters are basically invariant; however, the change ranges of the parameters are different. The increases in the parameters with the rises in shed parameters and rainfall intensity are mainly attributed to the change in the rainfall on the insulator surface. The experimental results can provide references for the quantitative description of surface rainwater characteristics and the design of large-diameter composite post insulators for DC transmission systems.

The methodological approach for the determination of the pressure of artificial raindrops as a question of the theory of splash soil erosion

To the article the results of the theoretical and experimental researches are given on questions of estimates of the dynamic rate effect of raindrop impact on soil. The aim of this work was to analyze the current methods to determine the rate of artificial rain pressure on the soil for the assessment of splash erosion. There are the developed author’s method for calculation the pressure of artificial rain on the soil and the assessment of splash erosion. The study aims to the justification of evaluation methods and the obtaining of quantitative characteristics, prevention and elimination of accelerated (anthropogenic) erosion, the creation and the realization of the required erosion control measures. The paper considers the question of determining the pressure of artificial rain on the soil. At the moment of raindrops impact, there is the tension in the soil, which is called vertical effective pressure. It is noted that the impact of rain drops in the soil there are stresses called vertical effective pressure. The equation for calculation of vertical effective pressure is proposed in this study using the known spectrum of raindrops. Effective pressure was 1.4 Pa for the artificial rain by sprinkler machine «Fregat» and 5.9 Pa for long distance sprinkler DD-30. The article deals with a block diagram of the sequence for determining the effective pressure of rain drops on the soil. This diagram was created by the author’s method of calculation of the effective pressure of rain drops on the soil. The need for an integrated approach to the description of the artificial rain impact on the soil is noted. Various parameters characterizing drop erosion are considered. There are data about the mass of splashed soil in the irrigation of various irrigation machinery and installations. For example, the rate (mass) of splashed soil was 0.28…0.78 t/ha under irrigation sprinkler apparatus RACO 4260–55/701C in the conditions of the Ryazan region. The method allows examining the environmental impact of sprinkler techniques for analyzes of the pressure, caused by raindrops, on the soil. It can also be useful in determining the irrigation rate before the runoff for different types of sprinkler equipment and soil conditions.

К ВОПРОСУ ПОВЫШЕНИЯ ЭФФЕКТИВНОСТИ ИСПОЛЬЗОВАНИЯ ДОЖДЕВАЛЬНЫХ МАШИН ПОЗИЦИОННОГО ДЕЙСТВИЯ

Внедрение кассетной технологии выращивания рассады требует совершенствования мобильных дождевальных машин для обеспечения необходимого качества дождя, эффективности полива и требуемых эксплуатационных показателей. Мобильная дождевальная машина имеет крылья с насадками для орошения. Вращение дождевальных крыльев и осуществление полива центральной части круга обеспечивается за счет сил струй двух насадок секторного действия, работающих по принципу сегнерова колеса. Для полива внешней части круга и исключения попадания дождя на стенки теплицы на концевых частях крыльев установки монтируются дождевальные насадки кругового действия. Расход насадок определяется как сумма объёмов воды, попавшей в дождемеры при орошении. Значение дальности полета капель в середине сектора орошения в направлении факела принималось за радиус орошения насадки. Средний диаметр капель искусственного дождя определялся путем улавливания их в начале, середине и конце факела насадок на предварительно тарированной фильтровальной бумаге. Равномерность распределения искусственного дождя по площади орошения, т.е. коэффициенты полива насадок определялись статистическим методом как отношение числа случаев эффективного, недостаточного и избыточного поливов к общему числу случаев. На основе полученных данных получена столбчатая диаграмма, отражающая уровень осадков зоны полива в соответствии с расположением дождемеров. На основании полученного уравнения регрессии построена поверхность распределения слоя осадков по площади полива с учетом сглаживания. Для обеспечения равномерности полива задавались величиной полива. Просуммировав уровни осадков на соседних позициях, можно задаться требуемым уровнем осадков при перекрытии. Полученное уравнение решается методом итераций, для заданного радиуса полива можно определить величину перекрытия, то есть расстояние между соседними позициями. Рациональное расстояние между соседними позициями дождевальной установки определяется радиусом полива и функцией распределения осадков по площади полива.To introduce cassette technology for growing seedlings, mobile irrigation machines should be improved to ensure the necessary rain quality, irrigation efficiency, and required performance indicators. The mobile sprinkler has wings with irrigation nozzles. The rotation of the sprinkler wings of the installation and the irrigation of the central part of the circle is ensured by the jet forces of the two nozzles of sectorial action, working on the principle of a segner wheel. To irrigate the outer part of the circle and to prevent rain from entering the walls of the greenhouse, sprinkler nozzles of circular action are mounted on the end parts of the wings of the installation. The nozzle flow rate is defined as the sum of the volumes of water that fell into the rain gauges during irrigation. The value of the flight range of the droplets in the middle of the irrigation sector in the direction of the torch was taken as the radius of irrigation of the nozzle. The average diameter of the artificial rain droplets was determined by trapping them at the beginning, middle and end of the nozzle torch on precalibrated filter paper. The uniform distribution of artificial rain over the irrigation area, i.e. nozzle irrigation coefficients were determined by the statistical method as the ratio of the number of cases of effective, insufficient and excessive irrigation to the total number of cases. Based on the data obtained, a bar chart is obtained that reflects the level of precipitation in the irrigation zone in accordance with the location of the rain gauges. Based on the obtained regression equation, a surface is constructed for the distribution of the sediment layer over the irrigation area, taking into account smoothing. To ensure uniform watering, we set the amount of watering. Having summed up the precipitation levels at neighboring positions, you can set the required precipitation level at overlapping. The resulting equation is solved by the iteration method, for a given irrigation radius, you can determine the amount of overlap, that is, the distance between adjacent positions. The rational distance between adjacent positions of the sprinkler is determined by the radius of irrigation and the distribution function of precipitation over the irrigation area. Key words: irrigation, sprinkler, sheltered soil, cassette method, seedlings.