Ivan Volodymyrovych Pavlenko

Static and Dynamic Analysis of the Closing Rotor Balancing Device of the Multistage Centrifugal Pump

In this paper the methods of static and dynamic analysis of the closing rotor balancing device of the multistage centrifugal pump are represented. On an example of the feed pump PE 600-300 static and dynamic characteristics are determined. Defined the resonance frequencies and investigated stability of the system “pump rotor – automatic balancing device – pressure difference regulator”. The dependence for the pressure difference and conditions to ensure reliable operation of the locking rotor balancing device are determined.

Scientific and Methodological Approach for the Identification of Mathematical Models of Mechanical Systems by Using Artificial Neural Networks

The article is aimed at developing the scientific and methodological approach of using artificial neural networks (ANN) for solving applied problems in the field of mechanical engineering. This approach is based on the comprehensive implementation of ANN with the modern methods of numerical analysis (e.g., the finite element method) and analytical methods of the research with the use of mathematical modeling of the dynamic state for mechanical systems. Conceptual schemes for the implementation of the abovementioned approach are proposed for solving a number of interdisciplinary problems, such as investigation of the dynamics for rotary machines and hydroaeroelastic interaction of gas-liquid mixtures with deformable structural elements, as well as the dynamic analysis of fixtures. The main advantages of the proposed approach in comparison with the traditional regression analysis are the ability to learn and improve the ANN architecture, and to solve nonlinear problems of the parameters’ identification for mathematical models by using data of the results of physical experiments and numerical simulations. This approach allows refining parameters of the linear and nonlinear mathematical models describing the complicated mechanical and hydro-mechanical interactions under the impossibility of determination of an absolutely precise solution of the equations describing the process, as well as the incompleteness of the initial data.

Fundamental Approach for Analysis of Dynamic Characteristics of Fixtures

Present work is aimed at research of locating and clamping process of prismatic parts in fixtures during the machining on drilling-milling-boring machines. The fundamental approach for developing mathematical modeling of the system “fixture – workpiece” has been proposed. It allows to determine critical frequencies of functional elements oscillations and amplitude-frequency response characteristics, as well as dynamic component of fixture deformations at operating frequency of the machining process. The developed mathematical model is evaluated by numerical calculations of spectrum of critical frequencies considering the stiffness of cutting tool. The further researches are directed on the development of the methodology of calculation of the system “fixture – workpiece” by computer means of numerous realization and development of practical recommendations regarding its use during fixture design.

Modelling of Liquid’s Distribution and Migration in the Fibrous Filter Layer in the Process of Inertial-Filtering Separation

The obtained solution of the mathematical model of liquid’s distribution and migration in the filter layer as flow model in the fibrous environment, which describes the non-pressure filtration motion in the gravity field of the separated liquid film from the gas-drop flow, allows to determine the saturation conditions of the free volume of the filter layer, distribution of speed and pressure under the conditions of free liquid’s movement in the filter layer, as well as to calculate the required cross-sectional area of the thin-layer fibrous filter element and the optimum height of the location of the overflow chutes for draining the separated liquid from the inertial-filtering to the drainage channels in order to avoid the secondary removal of droplets with the turbulent gas flow. As a result, the application rate of the separated liquid which falls from the filter element of the inertial-filtering separation channel to the drainage channels is obtained, as well as the dependence for the overflowed gutter of diverting the separated liquids from the inertial-filtering to the drainage channels is presented.

Granulation Process of the Organic Suspension: Fluidized Bed Temperature Influence on the Kinetics of the Granule Formation

The authors of the article present and prove the possibility of reducing the economic and environmental indicators in the processes of mineral fertilizers granulation by means of recycling and using organic agricultural waste. It is shown that such waste products are in the form of very moist suspensions, therefore, in order to minimize energy consumption for their processing, the optimal technology for granular product preparation is granulation in the fluidized bed apparatus. For this purpose there has been conducted the physical modelling of the granule formation process and one found out the conditions of suspended layer formation, which determine the nature of the dispersed suspension and dispersed solid phase interaction. One has experimentally established the temperature regimes of organic suspensions granulation and determined the operating parameters of the process. The kinetics of coarsening of granules was studied depending on the temperature of dehydration of organic suspensions. Analytical dependencies that are determined by the heat transfer coefficient are obtained to determine the time and temperature of granule heating.

Application of Artificial Neural Network for Identification of Bearing Stiffness Characteristics in Rotor Dynamics Analysis

In this article the implementation of the mathematical model for rotor oscillations on non-linear bearing supports for the multistage centrifugal compressor is considered by using the computer program “Critical frequencies of the rotor”. It realized the finite element mathematical model, which allows taking into account the non-linear dependence of bearing stiffness on the rotor speed, as well as gyroscopic moments of inertia of impellers and shell-type parts. The artificial neural network “Virtual Gene Developer” software is proposed for evaluating the operating parameters of the approximating curve “bearing stiffness – rotor speed” by the dataset of numerical simulation results in the abovementioned software. Actual parameters of non-linear bearing stiffness are obtained by the results of the experimental research of rotor critical frequencies for the multistage centrifugal compressor 295GC2-190/44-100M on the experimental accelerating-balancing stand “Schenck”. The main advantages of the proposed approach and methodology for application of Artificial Neural Networks are stated.