Wyniki wyszukiwania - BazTech

1

Structural modelling of throttle diagrams for measuring fluid parameters

Pistun Y., Matiko H., Krykh H., Matiko F.

Metrology and Measurement Systems

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2018

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Vol. 25, nr 4

659--673

EN

In the paper there are presented tools for structural modelling of throttle diagrams that are developed as a basis to building transducers used for measuring fluid parameters. The definitions of throttle diagrams are improved and their classification is developed. Dependences are obtained to calculate the number of measuring channels in a throttle diagram and the number of possible variants of measuring transducers using the combinatory apparatus. A procedure for mathematical description of throttle diagrams in the form of graphs is proposed which makes it possible to obtain all diagrams with different measuring channels on the basis of certain throttle diagram. The model is developed in the form of a graph. A schematic diagram and a mathematical model of a transducer measuring physical and mechanical parameters of Bingham plastic fluid are developed based on a throttle diagram.

2

Effect of flow pulsations on the accuracy of differential pressure flowmeters

Kostyk I., Matiko F., Fedoryshyn R.

Challenges of Modern Technology

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2017

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Vol. 8, no. 1

23--31

EN

This work deals with investigation of influence of flow pulsation on the accuracy of gas flow rate and volume measurement by means of the differential pressure flow meters. 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 flow rate 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 flow rate 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.

3

CFD simulation and experimental study of ultrasonic flowmeters

Roman V., Matiko F., Fedoryshyn R.

Challenges of Modern Technology

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2017

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Vol. 8, no. 1

37--43

EN

This paper deals with CFD simulation and experimental study of ultrasonic flowmeters. A mathematical model of an ultrasonic flowmeter (USM) was built for studying the errors of flow measurement in disturbed flows. The method of defining the position coordinates of the acoustic paths and their weighting factors was improved based on the Gauss-Jacobi method of integration (i.e. the weighting function was improved) which provided the possibility to raise the accuracy of the turbulent flow velocity integration. The effectiveness of the improved method was verified using the Salami functions. New methodology for improving the mathematical model of USM is proposed. According to this methodology the dependence of the calibration factor on the Reynolds number is introduced into the model. A technique for studying the errors of USM in disturbed flows was developed on the basis of the proposed methodology. The developed technique was verified by comparing the CFD simulation results for a 3D model of an acting USM with the experimental results for this meter obtained by means of a reference test rig. The deviation of the simulation results from the obtained experimental data is not more than 1 %. Recommendations on defining the pipe straight lengths for the double-path chordal flowmeters were developed on the basis of the investigation results.