Volume 3, Number 2 (2017)
Reduction of Hydrodynamic Flow Measurement Error of
Chordal Ultrasonic Flowmeter
Fedir Matiko, Vitalii Roman , Ivanna Kovalchuk
Lviv Polytechnic National University, S. Bandery St., 12, Lviv, 79013, Ukraine
Received: November 08, 2017. Revised: November 20, 2017. Accepted: December 06, 2017.
© 2017 The Authors. Published by Lviv Polytechnic National University.
Abstract
In this work, ways of reducing the hydrodynamic flow measurement error of chordal ultrasonic flowmeter for the distributed location schemes of their acoustic paths are investigated. The method of calculating optimal location coordinates of the acoustic paths of ultrasonic flowmeters is considered in detail, using 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 arrangement of acoustic paths for chordal schemes of two- and three-path ultrasonic flowmeters. It was established that optimization of the location scheme of the acoustic paths of chordal ultrasonic flowmeters allows reducing the hydrodynamic flow measurement error to the value of 0.05 % (for two-path flowmeters) and 0.1 % (for three-path). The developed approach is convenient when designing multipath ultrasonic flowmeters and their research in laboratory conditions.
Keywords: ultrasonic flowmeter; hydrodynamic error; power law; acoustic paths; chordal scheme.
Література – 10.
Energy Efficiency of Refrigerating Ejector Systems for the Condensation
of Oil Product Liquid Hydrocarbons
Iegor Butovskyi , Volodymyr Kogut, Volodymyr Bushmanov, Mykhailo Khmelniuk
Odessa National Academy of Food Technology, Educational and Scientific Institute of Refrigeration, Cryotechnology and Ecoenergy, 1/3, Dvorianskaya Str., Odessa, 65082, Ukraine
Received: September 30, 2017. Revised: October 31, 2017. Accepted: November 10, 2017
© 2017 The Authors. Published by Lviv Polytechnic National University
Abstract
The oil processing enterprises are the largest consumers of fuel and energy resources, heat and electrical energy. Efficiency, rationality of their use in oil refining processes in many respects is defined by overall performance of processing equipment. Feature of processes for processing a hydrocarbon raw material is that technology processes are imperfect. One of the priority directions of increase in efficiency of energy saving of oil processing productions is the maximum use of recuperation of warmth and optimization of operating modes of technology installations. The article focuses on the use of refrigerating ejector systems at the solution of the most important problems of the oil processing industry. The offered systems allow resolving effectively issues of energy saving and rational consumption of fuel and energy resources of the oil industry enterprises. The scheme solutions in the industry are the priority direction of energy saving policy.
Keywords: refrigerating ejector systems; liquid hydrocarbons; energy efficiency; energy saving; hydrocarbon raw material.
Література – 9.
Modern Wind Turbines Capacity Utilization in Real Conditions
Kostiantyn Pokrovskyi , Olgerd Mavrin, Andriy Muzychak, Volodymyr Oliinyk
Lviv Polytechnic National University,12, S. Bandery str., Lviv, 79013, Ukraine
Received: October 20, 2017. Revised: November 09, 2017. Accepted: November 23, 2017
© 2017 The Authors. Published by Lviv Polytechnic National University
Abstract
The development of the national wind power industry in Ukraine faces a number of problems because of the lack of sufficient information on the peculiarities of the operating modes of wind farms under real-life conditions. This applies to wind load indices in different regions, estimates of the performance of wind power plants with different types of wind turbines. One of the important characteristics of the potential capabilities of a wind power plant in the grid is the time and rate of utilization of installed capacity (installed capacity utilization factor – ICUF), which are widely used in the design of power plants. The paper presents the results of calculating the characteristics of the production potential of wind power plants with generators of different types and capacities, which are defined in terms of time and coefficient of utilization of the installed capacity. It is shown that such characteristics of the wind power station uniquely characterize the efficiency of the application of a specific wind generator in real conditions for use in design calculations.
Keywords: wind turbine; wind station; time of use of installed capacity; coefficient of utilization of installed capacity.
Література – 11.
Microwave Device for Obtaining Extracts from Plant Materials
Natalia Volgusheva, Kateryna Heorhiiesh , Leonid Boshkov
Odessa National Academy of Food Technologies, Ukraine, 65082, Odessa, Dvoryanska St., 1/3
© 2017 Authors. Published by Lviv Polytechnic National University.
Received: October 11, 2017. Revised: November 02, 2017. Accepted: November 13, 2017.
Abstract
A method for obtaining biopesticides from plant materials based on application of a microwave electromagnetic field in the process of extraction is being studied. The article presents results of an experimental study of the efficiency of microwave extracts. The expediency of extracting biologically active substances in a microwave field is shown. The application of the method makes it possible to proceed to the production of large volumes of preparations and to reduce the volumes of chemical agents. A device is proposed for implementing this method. In order to increase the productivity, it is reasonable to develop an extractor of continuous action, and for this purpose the input and output channels should be designed so that their length corresponds to the length of the below cutoff waveguide that provides operation safety of the personnel working with the microwave device. For transfer of electromagnetic energy, it is rational to use horn antennas, and diameter of the channel through which raw materials with extractant pass should not exceed two depths of penetration taking into account the effect of thermal conductivity.
Keywords: biopesticides; microwave field; plant materials; efficiency; microwave screw extractor.
Література – 8.
Model of Biomineralization of Ferrum Compounds by Gallionella Cells Immobilized on Contact Loading of Bioreactor
Oleksandr Kvartenkoa, , Iryna Gryukb, Larysa Sabliyc
aNational University of Water Environmental Engineering, 11, Soborna St. Rivne, 33028, Ukraine
bRivne State Humanitarian University, 12, Stepana Bandery St., Rivne, 33028, Ukraine
cNational Technical University of Ukraine " Igor Sikorsky Kyiv Polytechnic Institute",
37, Peremohy Ave., Kyiv, 03056, Ukraine
Received: November 21, 2017. Revised: December 03, 2017. Accepted: December 06, 2017.
© 2017 The Authors. Published by Lviv Polytechnic National University.
Abstract
In the underground waters not polluted by organic compounds the bivalent iron occurs in the form of hydrocarbonates. An inseparable part of ferrum ions are ferrum bacteria. As a result of the literature review carried out it is determined that up till present no mechanism of the impact of additional source of non-organic carbon on the processes of in-cellular metabolism of Gallionella type bacteria had been established. The aim of the paper is the determination of the effect of the additional source of non-organic carbon in the form of Na2CO3 on processes of metabolism and the rate of biochemical oxidation of iron compounds by bacteria Gallionella sp. and the development of the possible mechanism of the assimilation of non-organic carbon in the recovered pentose phosphate cycle. The comprehensive scheme of activating bacteria metabolism developed by us testifies to the possibility of increasing the energy capacity of recovered pentose phosphate cycle, the acceleration of metabolism cycles and the rate of pumping electrons via the fermentative cell system. The totality of presented processes results in speeding up the fermentative oxidation of Fe2+ on the surface of a cell with the final formation of matrix structures of biominerals and the increased efficiency of bioreactors operation.
Keywords: biomineralization of iron compounds; iron bacteria; electrons; respiratory chain.
Література – 14.
Improvement of Pulse-Width Modulation Algorithm
for Thermal Plant Control
Roman Fedoryshyn , Sviatoslav Klos, Volodymyr Savytskyi, Sergiy Kril
Lviv Polytechnic National University, 12 Stepan Bandera St., Lviv, 79013, Ukraine
Received: November 08, 2017. Revised: November 29, 2017. Accepted: December 06, 2017.
© 2017 The Authors. Published by Lviv Polytechnic National University.
Abstract
The results of the pulse-width modulation algorithms analysis are presented in the paper. The following two algorithms are analyzed: pulse-width modulator (PWM) based on the sawtooth waveform generator and PWM based on an integrator and a switch element. Mathematical formulae for designing the tuning parameters of PWM algorithms are presented. An improved PWM algorithm is suggested for a programmable logic controller (PLC) operating with integer variables without a filter of the input signal. The improved algorithm provides elimination of the influence of the input signal’s noise on the PLC output signal. PLC output relay contact bouncing is eliminated by means of the improved algorithm. The reliability of PLC is improved and the operation time of PLC output relay contact is prolonged thanks to the improved PWM algorithm. The example of PWM application in an automatic controller for controlling a thermal plant is presented. The advantages of the improved PWM algorithm application are demonstrated. The technique for PWM pulses period defining with taking into account the dynamical properties of the controlled plant is presented.
Keywords: pulse-width modulator; algorithm; duty cycle; integrator; comparator; switch.
Література – 9.
Element in Rotational Paper Pulp Consistometer
Yevhen Pistun, Bohdan Kril, Oleksandr Romaniuk , Oleksandr Kril
Lviv Polytechnic National University, 12 Bandery St., Lviv, Ukraine, 79013
Received: November 16, 2017. Revised: November 30, 2017. Accepted: December 06, 2017.
© 2017 The Authors. Published by Lviv Polytechnic National University.
Abstract
This paper presents the results of theoretical and experimental testing of an optical rotation angle sensor of rotational paper pulp consistency meter. It is suggested that a specialized device consisting of two discs with the diameter as large as possible should be applied in the rotational consistency meters. There are holes in the disks. One more optocoupler should be applied for registering the beginning of the signal processing of separate measurements in order to reduce the root-mean square error. The measurement cycle of the sensitive element rotation angle is conducted within a predetermined number of full turns of the main shaft. The research results can be applied during development of the paper pulp rotation consistency meters based on the compensation of the viscous friction torque and based on the direct measurement of the viscous friction by defining the rotation angle of the sensitive element.
Keywords: paper pulp consistency; measurement; rotation consistency meter; optical sensor; magneto-electric transducer.
Література – 9.
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