Volume 2, Number 1 (2016)
Myroslav Tykhan
Lviv Polytechnic National University, 12, S. Bandery str., Lviv, 79013, Ukraine
Received: April 18, 2016. Revised: December 12, 2016. Accepted: December 23, 2016
© 2016, Tykhan M. Published by Lviv Polytechnic National University
Abstract
Nowadays, industrial development creates new and more complex processes leading to emergence of specific conditions for use of sensors and therefore specific measurement tasks. These circumstances lead to new requirements both for the methods of measurement and for sensors that implement these methods. Developments in microelectronic technologies and materials science have led to a significant number of types of pressure sensors. However, in recent years, despite the growing number of sensors range, it is in high-tech industries that the need for pressure sensors with fundamentally new features and characteristics has increased dramatically. This is caused by the need to rapidly measure unsteady pressure in real time, with a normalized error mostly within the static one. Taking this into account, the features of non-stationary pressure measurement in real time are analyzed in this paper and the necessary and sufficient requirements for sensors that allow their effective use are outlined. Thus, the goal of this work is the analysis of the process of measuring the non-stationary pressure in real time, aimed at identifying the peculiarities of the measurement problem and development of ways of its solution.
Keywords: peculiarities; measurement; unsteady; pressure; real time; sensor.
References – 18
Algorithmic Method for Precision Enhancement
of Paper Pulp Blade Consistometer
Oleksandr Romaniuk , Bohdan Kril, Oleksandr Kril
Lviv Polytechnic National University, 12, S. Bandery str., Lviv, 79013, Ukraine
Received: November 07, 2016. Revised: December 12, 2016. Accepted: December 23, 2016
© 2016, Romaniuk O., Kril B., Kril O. Published by the Lviv Polytechnic National University
Abstract
The article deals with the algorithmic method for precision enhancement of paper pulp blade consistometers . In the said method, the current strength in the winding of a moving coil of a magnetoelectric transducer in the steady regime of sensor`s blade motion condition is measured during its movement in downstream and upstream directions. Thus, we can minimize the error resulting from the impact of changes in flow velocity relative to paper pulp measuring blade of the consistometer. Schematic diagram of a paper pulp consistometer with paper pulp flow velocity compensation is presented. Dependence of voltage and current versus time on the outputs of the main blocks of presented paper pulp consistometer with compensation of paper pulp flow velocity influence is considered. Influence of paper pulp flow velocity and consistency on the dependencies of current versus time for the coil of a magnetoelectric transducer of a paper pulp consistometer is described.
Keywords: blade consistometer; blade consistency meter; paper pulp; consistency; non-Newtonian fluid.
References – 10.
Preparation of Papers for the Journal EECS
Investigation of Differential Pressure Flowmeters
Accuracy in Pulsating Flows
Roman Fedoryshyn , Fedir Matiko, Ihor Kostyk, Yevhen Pistun
Lviv Polytechnic National University, 12, S. Bandery str., Lviv, 79013, Ukraine
Received: November 16, 2015. Revised: March 09, 2016. Accepted: December 23, 2016
© 2016, Fedoryshyn R., Matiko F., Kostyk I., Pistun Y. Published by Lviv Polytechnic National University
Abstract
This work deals with the investigation of influence of flow pulsation on the accuracy of gas flowrate and volume measurement by means of the differential pressure flowmeters. Experimental studies of the step response curves of an impulse line with a pressure transducer (PT) were carried out with application of a high-frequency analog-to-digital converter of the pressure signal in the PT chamber. Mathematical model of an impulse line with a PT was built. This model provides simulation and investigation of the transient processes with high accuracy. The influence of the impulse line design (length, diameter) on the step response curves and on the frequency response curves as well as on the resonant frequency of the oscillating system (an impulse line with a PT chamber) was studied. The systematic errors of flowrate and volume measurement due to the resonance in the impulse lines which was caused by flow pulsation were simulated and studied for an acting differential pressure natural gas metering system. On the basis of the calculation results, it was defined that amplification of the amplitude of the oscillating signal of the differential pressure due to the resonance may lead to a negative systematic error of gas volume measurement. The systematic errors of gas flowrate and volume measurement caused by the flow pulsation can be reduced by choosing the correct design of the impulse lines in order to avoid the resonance.
Keywords: flowmeter; flow pulsation; measurement; pressure transducer; natural gas.
References – 9.
Determination of Wood Fractional Composition Effect on Gasification Process
Stepan Lys , Yosyph Mysak, Taras Kravets
Lviv Polytechnic National University, 12, S. Bandery str., Lviv, 79013, Ukraine
Received: October 01, 2016. Revised: October 07, 2016. Accepted: December 23, 2016
© 2016, Lys S., Mysak Y., Kravets T. Published by Lviv Polytechnic National University
Abstract
The heating value of synthesis gas derived as a result of the fuel gasification can vary depending on various factors. The main factors that affect the process of gasification is the fractional composition of wood; the amount of air fed to the gasification chamber; the height of the active layer and a series of other factors, dependent on fuel which is gasified and parameters of the gasifier. Any type of wood has to be to ground up for subsequent thermal processing. Depending on the production necessity, wood is ground up to technological chips of different fractions by chipping machines (also called wood chippers, shredder). The choice of chippers type depends on the need. Modern chipping machines allow making fine tuning of the source material by wood size. Considering the deficit and cost of energy carriers to the forefront using waste of wood chippers as fuel for gas-generator installations and solid fuel boilers.
Keywords: calorific value of synthesis gas; gas-generators installation; wood gasification process; fractional composition of wood.
References – 8.
Controlled Switched Reluctance Motors with Energy Capacitor
Vasyl Tkachuk, Lidiya Kasha , Ihor Bilyakovskyy, Mykhajlo Haj
Lviv Polytechnic National University,12, S. Bandery str., Lviv, 79013, Ukraine
Received: June 30, 2016. Revised: November 28, 2016. Accepted: December 23, 2016
© 2016, Tkachuk V., Kasha L., Bilyakovskyy I., Haj M. Published by Lviv Polytechnic National University
Abstract
One of the most simple in terms of construction, the most practically feasible and reliable motors is a switched motor with salient-pole stator, concentrated coils and its winding and toothed passive rotor. Such motor is simpler, cheaper and more practically technical than asynchronous motor and by control characteristics does not concede to DC motors. The basic electrical scheme of a commutator with capacity buffers of energy of switched reluctance motor and circumscribed, the new phase-width mode by regulating frequency of reversion of such drives is offered. The width-phase speed control, where there is a functional relationship, is described in this paper.
Keywords: switched reluctance motor; width-phase control; energy capacitor; electronic commutator.
References – 8.
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