The difficult operating conditions during the pumping of abrasive solid mediums lead to the rapid wear of the mechanical parts of the pumps. The use of jet pumps can significantly increase the reliability and durability of pumping equipment. However, direct-flow jet pumps have low efficiency. The use of the centrifugal force led to the creation of new jet pumps - vortex chamber pumps. Their performance indicators are better than direct-flow jet pump ones. The geometric parameters of the flow channel of the vortex chamber pumps were optimized. The study was carried out experimentally and numerically. Numerical simulation is based on solving the RANS equations with the shear stress transport turbulence model. The geometrical dimensions of the vortex chamber pump with the best performance indicators such as pressure and flow are found. The maximum achievable operating parameters of the vortex chamber pump are analyzed. The comparison of simulation results with experimental data is made.
An analysis of the condition of implementation of projects in agricultural production is carried out. The disadvantages of existing methods and models of planning of the content and time of execution of works in the projects, which mostly do not take into account the changing components of their project environment, are substantiated. The proposed methodology for justifying the models of a changing project environment for harvesting grain, oilseed and legume crops is based on the analysis of official statistics of agrometeorological stations and involves the implementation of production experiments, which makes it possible to increase the accuracy of the results. It has been established that the dewy periods of time in the projects for the collection of early oilseeds, cereals and legumes are characterized by a probabilistic distribution of the time of occurrence of dew and its duration. The indicated regularity and the established correlation relationship between the occurrence of dew and its duration are the main components of the model. The substantiated model of the pink period of time allows to take into account the changing events of the project environment and to improve the quality of the content management process and the time of performance of the harvesting work. It is established that the deficit of humidity in the air, in which the performance of harvesting is effective, changes over the course of the day by parabolic dependence. Its maximum value depends on the agrometeorologically acceptable duration of the works in the projects of harvesting early oilseeds, grain and legume crops, which is the basis for substantiating the model of the air humidity deficit and taking into account its impact on the implementation of works in these projects. The obtained results of the research are the basis of development of simulation models of projects for the collection of early oilseeds, grain and legume crops to improve the accuracy of determining the use indicators and resource requirements for the implementation of these projects. The obtained models increase the quality of management decision making in the projects of harvesting early oilseeds, grain and legume crops.
Introduction. To represent our national goods at the Western market it is necessary to ensure, first of all, the competitiveness of local products through complex mechanization of technological processes, labour costs reduction, increasing yields and quality of received products. The aim of the research is to provide the comparative analysis of technology and machines for potato harvesting, to determine the main factors that influence the agricultural technical indicators of harvesting equipment, to develop technological process patterns and to examine the strategies for improving the potato root-and-harvest machines. Methods and methodology. The research was carried out on the basis of technological and constructional analysis of technology and machines for potato harvesting. The methods of comparison and mathematical modelling of technological processes were used in the study. The research studies of Ukrainian and foreign scientists on technology and machines for potato harvesting were used as information base of our paper. Results. A comparative analysis of technology and machines for potato harvesting made it possible to determine the main factors that influence the agricultural performance of harvesting machinery and to develop the technological process for a digger, a double-loader digger and a harvester (harvesting machines). A theoretical model of the technological processes of harvesting machines includes both uncontrolled and controlled factors that influence the choice of a potato harvesting technology of a digger, a double-loader digger and a harvester. Nevertheless, the first factors are connected, primarily, with the conditions of potato growth and its biological properties, and the second factors deal with the organizational and technical measures, including the improvement of the working bodies of machines (cutting, dirt digging through, top separation, longitudinal hump with cut roller and other constructive and kinematic parameters), quality of received products, length and terms of potato storage, available farming human resources, free vehicle in the period of harvesting, farm potato storage, farm equipment for potato cleaning and sorting.
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