Усовершенствованный экспериментально-теоретический метод расчёта траектории частиц в пневмосепарирующем канале А.И. Б у р к о в , А.Л. Г л уш к ов , В.А. Л а зы к и н ФГБНУ «Федеральный аграрный научный центр Северо-Востока имени Н.В. Рудницкого», г. Киров, Российская Федерация Представлен усовершенствованный экспериментально-теоретический метод (ЭТМ) расчёта траектории частиц в пневмосепарирующем канале (ПСК). Особенностью данного метода является то, что математическое моделирование поля скоростей воздушного потока в зоне сепарации производится на основе измерения их факти ческих значений при номинальной зерновой нагрузке, а расчёт и построение траекторий частиц выполняется с учётом их рикошета от стенок канала. Усовершенствованный метод включает в себя три этапа. На первом эта пе экспериментально измеряется векторное поле скоростей воздушного потока в центрах равновеликих прямо угольников, расположенных в зоне сепарации по всей высоте и глубине ПСК, при номинальной зерновой нагрузке. На втором этапе на основании определённых значений векторов скоростей в центрах прямоугольников составля ются математические выражения, описывающие вертикальные и горизонтальные составляющие этих скоростей в соответствующих сечениях по осям координат. На третьем этапе составляется система дифференциальных уравнений движения частицы в ПСК относительно декартовой системы координат, и рассчиты ваются их траек тории. Усовершенствованный ЭТМ повышает точность расчета траектории частиц в ПСК и аэродинамических параметров частиц на выходе из него, что ускоряет процесс оптимизации конструктивных параметров канала и присоединённых к нему элементов пневмосистемы.

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The article presents the comparison testing of particle trajectories in the pneumatic separation channel (PSC) of the pneumatic seed separator SP-2F and its bend, calculated using computer simulation method and two experimental-theoretical methods. They are based on taking into account the real airflow velocity field. In the first variant, the velocity field was measured in an idle mode, in the second at the nominal grain load. The studies were carried out in a vertical PSC with a supporting grid divided into two parts by a partition wall. In the variant with the theoretical velocity field the trajectories of light and grain impurities in the first part of the PSC are shifted closer to the outer wall. In the second part of the channel, particles with hovering speed of 8.0...10.0 m/s are carried upwards, and with hovering speed of 11.0 m/s they fall down into the purified material. In the variant of the experiment in an idle mode, particles with the hovering speed of 7.0...10.0 m/s rise up in the second part of the PSC. In the variant with grain load, particles with the hovering speed of 7.0...9.0 m/s rise upward and ricochet off the inner walls of the PSC and a bend wall, and particles with the hovering speed of more than 10.0 m/s fall down into the purified material. In the variant of the experiment with the grain load, the particle velocity with the hovering speed of 5.0...9.0 m/s at the exit of the PSC bend is more evened as compared to other options - 2.3...2.7 m/s, and the velocity vector of most particles is directed at a lower angle to the horizontal: from 4 up from the horizontal to 17 down from the horizontal. The most accurate is the calculation of particle trajectories using the velocity field in the PSC at the nominal grain load. The results of the study can be useful in the theoretical substantiation of the design parameters of pneumatic systems of grain cleaning machines.

The paper analyzes the separation of heaps in the separation chamber of the pneumatic system in a fractional grain pretreatment machine. The finding is that the components of feed grain may reach the sedimentation chamber. A reflective partition must be in place to fully capture them in the separation chamber. The paper analyzes the estimated trajectories of grain particles of various grains to optimally position the front edge of this partition. The Selma feed oats are found to be moving the closest to the outer wall, which is why their trajectories define where the front edge of the reflective partition must be. When placing the front edge of the reflective partition at 0.25 m off the outer wall of the pneumatic system, the vertical setpoint is 0.515 m. To confirm the theoretical findings, the research team conducted experiments to find out the exact vertical and depthwise distribution of grain components in the separation chamber. The experiments used a laboratory bench version of the pneumatic system like those used in grain pretreatment machines. For experiments, the team prepared a grain mix that comprised Abava barley grains (50 % large-particle grains, 45 % small-particle grain) + 5 % of light impurities. The experiments showed that to prevent the grain from infiltrating in the dust exhaust located between the reflective partition and the outer wall, the front edge of the partition must be set at 0.47 to 0.55 m vertically, 0.25...0.30 m off the outer wall, which confirms the estimates.

The article studies the separation chamber of the pneumatic seed separator including the definition of its key design parameters and determining the best position of its rotary valve edge during wheat seed sorting. The experiment planning method helped us consider the effects the vertical X (x1) and horizontal Y (x2) positions of the rotary valve edge relative to the inlet edge in the separation chamber wall have on the distribution of grain material components in Fractions II and III. We established that it was possible to obtain Fraction II wheat, consistent with RSC commercial reproduction seed purity category with Fraction I seeds consistent with ES elite seed category and permissible loss levels. The required purity of Fraction II is achieved with the separation chamber minimum length of LR.K = 0.55 m and the rotary valve length of LK = 0.28 m. The separation chamber partition edge with the rotary valve is located 0.40 m away from the inlet edge of the front wall and 0.30 m below its level. The highest purity of Fraction II PII = 98.4% is achieved when the rotary valve edge is set in position х1 = -1 (ХK = 0.25 m) and х2 = -1 (YK = -0.10 m). The highest purity of Fraction III with permissible levels of sound seed loss (Fraction IV) is achieved when the outlet edge in the separation chamber wall is positioned at the same level as the inlet edge (the duster inlet height HV = 0.21 m). The results of the research can be used in the development of pneumatic systems for seed-purifying machines.