Обґрунтування параметрів процесу і розробка пневмосепарувального каналу зернових сепараторів : автореф. дис. на здобуття наук. ступеня канд. техн. наук : 05.05.11 - Машини і засоби механізації сільськогосподарського виробництва

Abstract

У дисертації вирішене наукове завдання, яке направлене на підвищення ефективності процесу очищення зернових сумішей шляхом попереднього їх розшарування пристроєм пневмосепарувальних каналів барабанних зернових сепараторів. Запропоновано напрям інтенсифікації процесів очищення зернових сумішей, який ґрунтується на взаємодії фаз суцільних середовищ за реологічними законами з урахуванням їх попереднього розшарування розробленим пневмосепарувальним каналом. Розроблено математичні моделі динаміки розшарування зернових сумішей на повітропроникній лускатій поверхні та очищення у вертикальному каналі, в яких враховано вплив конструктивно-технологічних параметрів розробленого пневмосепарувального каналу, властивостей зернових сумішей. Розроблений пневмосепарувальний канал пройшов виробничу апробацію та впроваджений в серійне виробництво зернових барабанних сепараторів. Ефективність очищення зернових сумішей розробленим пневмосепарувальним каналом збільшена на 30…40%, що дозволило підвищити продуктивність зернових сепараторів на 23,5…29 %.

В диссертации решено научное задание, которое направлено на повышение эффективности процесса очистки зерновых смесей путем предварительного их расслоения устройством пневмосепарирующих каналов барабанных зерновых сепараторов. Предложено направление интенсификации процессов очистки зерновых смесей, которое основывается на взаимодействии фаз сплошных сред по реологическим законам с учетом их предварительного расслоения разработанным пневмосепарирующим каналом. Разработаны математические модели динамики расслоения зерновых смесей на воздухопроницаемой чешуйчатой поверхности и очистки в вертикальном канале, в которых учтено влияние конструктивно-технологических параметров разработанного пневмосепарирующего канала, свойств зерновых смесей. Разработанный пневмосепарирующий канал прошел производственную апробацию и внедрен в серийное производство зерновых барабанных сепараторов. Эффективность очистки зерновых смесей разработанным пневмосепарирующим каналом повышена на 30…40%, что позволило увеличить производительность зерновых сепараторов на 23,5…29 %.

In the thesis decided the scientific task, which is aimed at improving the efficiency of process of grain mixtures cleaning by pre-stratification on the pneumatic separating channels of drum grain separators. For this purpose in the pneumatic separating channel before the basic vertical channel device, representing the permeable scaly surface is established. Particles of light impurities under influence of delamiring device are redistributed in the grain mixtures layer, concentrating in its upper sublayers. The formed layer of grain mixture of a greater thickness is sent to the main vertical pneumatic separating channel, where it is cleaned by aerodynamic properties. This allows to increase the specific loading of the pneumatic separating channel, which intensifies the process of cleaning grain mixtures on grain separators. Mathematical modelling of grain mixes movement in working zones of developed pneumatic separating channel is based on interaction of phases of continuous mediums according to the rheological laws taking into account preliminary of grain mixes. The equations of motion of two-phase polydisperse medium were constructed with the help of which the regularities of particle velocity of grain mixtures and the coefficient of its stratification on the scaly air permeable surface were established. The conditions and parameters of fluidized of grain mixes, which determine the effectiveness of its stratification on the developed pneumatic separation channel are grounded. It has been established that the increase of the speed of blowing by air flow of grain mixture on the scaly surface of developed pneumatic separating channel, reduction of particle density of grain mixtures and the height of its layer, increase the stratification coefficients by 20...35%. For calculation and management of productivity of process of grain mixes cleaning the mathematical models are constructed: movements of the fluidized grain mix on a scaly air permeable surface; movement of pre-stratified grain mixture in vertical pneumatic separating channel of drum grain separators. The decision of models is obtained regularities of change of stratification coefficients and cleaning of grain mixes, trajectories of movement of impurities particles. It is determined that the use of pre-stratified grain mixtures increases the coefficients of its purification in the developed pneumatic separation channel for 18,3...47% to 0,68...1, compared to the base construction. The method of determination of speed and trajectory of grain mixture components in working zones of developed pneumatic separator channel, which is based on video shooting of particles of grain mixture with application of Pitot tube, micromanometer and anemonometer Testo 416 is offered. According to the set speed dependencies of "float" and the trajectory of particles the impurities experimentally confirmed its redistribution to the upper layers of grain mixture under the influence of air flow and scales, providing stratification. On condition of pseudo-liquefied grain mixture and its maximal strat ification the recommended ranges of variation of parameters of the developed pneumatic separator channel. Proposed methods with the developed software experimentally identified ranges variation of significant parameters of process of grain mixture cleaning: porosity and particle size of grain mixture components. According to the developed method the ranges of variation of grain mixture porosity were determined, which were investigated: wheat 0,48...0,56; corn 0,54...0,63; sunflower 0,57...0,65. The use of stratification device developed by pneumatic separator channel leads to increase of porosity of grain mixture for 12,2...17%, confirming the possibility of intensification of grain mixture purification process. The dependence of process of grain mixtures purification on condition of its preliminary bundles on the developed pneumatic separator channel is established. It is determined that the increase of air flow rate, in the explored ranges, increases the coefficient of bundle of grain mixtures by 9,3…21%. Established ranges of variation of coefficients bundle for grain mixtures: wheat 0,23…0,9; sunflower 0,12…0,22; corn 0,24…0,48. The increase of productivity of developed pneumatic separator channel at cleaning of prestratification grain mixture 3…42%, in comparison with the basic construction is established. The complex analysis of results of theoretical and experimental researches, conducted multifactorial experiment of process of grain mixes cleaning are established constructive and technological parameters of the developed pneumatic separating channel: angle of air permeable surface 41…430 ; length of air permeable surface 0,43…0,47 m; air flow rate on air permeable surface 2,3…2,7 m/s; speed of air flow in vertical channel 6,1…6,7 m/s; width of vertical channel 0,21…0,3 m. It was established that at the specified parameters the coefficient of stratification of wheat grain mixtures amounted to 30,53…31,75%, the coefficient of its purification developed by the pneumatic separating channel – 92,15…99,29 %. The production tests of the developed pneumatic separating channel on the grain processing plants have been established to increase the efficiency of process of corn grain mixtures cleaning, sunflower and wheat by 30…40% to 80…96%, which provides increased productivity of drum separators KBS 1270.4.00 for 23,5…29%. The developed normative-technical documentation on pneumatic separating channels with the delamifying device is introduced and used in serial production at KMZ Industries.