Litteris et Artibus
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Item Analysis of coke gas properties at operation of its metering systems(Lviv Polytechnic Publishing House, 2016) Dzhyhyrei, Viktor; Matiko, Fedir; Lviv Polytechnic National UniversityThe generalization and analysis of coke oven gas composition using the data of literary sources and coke enterprises are carried out in the paper. The range of pressure and temperature of coke gas during transportation is defined. The physical properties of coke gas (density, compressibility factor, adiabatic index, dynamic viscosity) that are the part of the equation of gas flowrate by method of variable differential pressure are investigated in the defined range of pressure and temperature. 25 gas mixtures with different composition were synthesized in order to make the analysis of dependency of physical properties versus pressure, temperature and composition of the mixtures. According to the results of the research the recommendations for the development of simplified methods for calculating the physical properties of coke oven gas are made.Item Efficiency criterion of CFD-modelling for studying the ultrasonic flowmeters(Lviv Polytechnic Publishing House, 2016) Roman, Vitalii; Matiko, Fedir; Lviv Polytechnic National UniversityThe paper presents a efficiency criterion of CFD-modelling for the research of ultrasonic flowmeters. He is a relative error of reproduction of mass flow rate in the i-th section 3D layout measuring pipeline. The authors investigated the influence of this criterion of effectiveness various options CFD-modelling.Item Hydrodynamic flow measurement error of ultrasonic flowmeters(Видавництво Львівської політехніки, 2017-12-23) Roman, Vitalii; Matiko, Fedir; Kovalchuk, Ivanna; Lviv Polytechnic National UniversityIn this work the essence of hydrodynamic flow measurement error of ultrasonic flowmeter (USM). The methods of eliminating this error are analyzed. One of these methods is considered in detail – optimization of the location schemes of chordal acoustic paths (APs) of USM. The optimization is performed on the basis of the analytical-empirical power law of the distribution of the velocity of the undistorted flow. As a result of the work, the authors calculated the optimal location of the APs for chordal schemes of two- and three-path USMs. It was established that optimization of the location schemes of APs chordal USM allows to reduce the hydrodynamic flow measurement error to a value of 0.05 %(for USMwith two hordal APs) and 0.1 %(for USMwith three chordal APs). The developed approach is convenient when designing multipath USM and their research in laboratory conditions.Item Determining of volume of natural gas losses caused by damages of distribution networks(Lviv Polytechnic Publishing House, 2015) Dzhyhyrei, Viktor; Matiko, Fedir; Klymkovskyi, Dmytro; Lviv Polytechnic National UniversityThe algorithm of calculation of gas volume losses caused by damages of above-grounded pipelines is proposed in this paper. The mathematical model of natural gas movement in the pipeline is developed for the implementation of the algorithm. The model is used to determine the parameters of the gas flow at the leakage point. The equation for calculation gas flowrate through the holes in the pipeline wall is developed on the basis of the formula of Saint-Venant-Wentzel. The equation is valid for subcritical and critical regime of gas flow. The equation for determining discharge coefficient of the holes in the pipeline wall for gas pressure up to 1.2 MPa is proposed.Item Investigation of ultrasonic flowmeter error in conditions of distortion of flow structure(Lviv Polytechnic Publishing House, 2015) Roman, Vitalii; Matiko, Fedir; Lviv Polytechnic National UniversityUltrasonic flowmeter error caused by distortion of flow structure has been investigated in this paper. Minimum number of acoustic chordal paths of multi-channel ultrasonic flowmeter was determined that ensures the error caused by distortion of flow structure less than the specified limits ±0.3 %. The authors used Salami velocity function as a model of distortion of flow structure. Acoustic path configurations of ultrasonic flowmeter were determined using classical numerical methods of integration of Gauss-Jacobi. The authors improved the flow rate equation of ultrasonic flowmeter by introduction of calibration coefficient that was determined using symmetric component of Salami function.Item Mathematical modeling and experimental study of impulse lines of flowmeters(Lviv Polytechnic Publishing House, 2015) Fedoryshyn, Roman; Matiko, Fedir; Kostyk, Ihor; Stefurak, Khrystyna; Lviv Polytechnic National UniversityMathematical model of an impulse line with a pressure transducer (PT) was built. This model provides the possibility to simulate and analyze the transient processes in an impulse line. Experimental studies of the step response curves of an impulse line with PT were carried out with application of a high-frequency analog-to-digital converter of the pressure signal in the PT chamber. The simulated step response curves were compared to the experimental ones. Maximum relative deviation of the simulated step response curves from the experimental ones is 6.3 %.