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1

Determination of kinematic parameters of the compressor unit applied to low-pressure petroleum gas

Aliyev Alesker M.

Nafta-Gaz

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2023

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R. 79, nr 4

252--256

EN

The collection and transportation of low-pressure gas released into the atmosphere from the oil fields is important in increasing gas production. This issue, which differs in its actuality, has both economic and pollution preveniton benefits. One such project, led by the UN Development Fund, was successfully implemented in the city of Siyazan, Azerbaijan. An electrically driven compressor unit of NQK-7/1-5 type with two oscillating cylinders is commonly used for such work. On visual inspection of the compressors undergoing repair, it was found that the seals in the pneumatic part and the elements of the cylinder-piston group are completely out of order, the gear teeth in the transmission part are broken, worn, the bearings are destroyed, the belts are torn, etc. Compressors sent for repair are almost always reassembled. A structural-kinematic analysis of the compressor installation was carried out to find out the causes of the existing malfunctions. For this purpose, a kinematic diagram of the conversion mechanism of the compressor – a slider-crank linkage mechanism was drawn up using the method of closed contours from projection equations relative to the X and Y axes, and based on the condition that the rotation angles of the piston and cylinder axes are equal, the instantaneous rotation angle, angular velocity and angular acceleration of the cylinder rotation, as well as instantaneous values of displacement, speed and acceleration of the piston inside the cylinder were found. It was shown that the designer's decision on the selection of the design scheme and determination of the product dimensions, which are one of the main issues in the design of the mechanism, should be made based on the results of the kinematic and dynamic analysis.

PL

Gromadzenie i transport gazu LPG uwalnianego do atmosfery z pól naftowych są istotnymi kwestiami jeśli chodzi o zwiększenie wydobycia gazu. Zagadnienie to, zróżnicowane pod względem realiów, niesie za sobą korzyści z punktu widzenia ekonomicznego jak i zapobiegania zanieczyszczeniu środowiska. Jeden z takich projektów, prowadzony przez Fundusz Rozwoju ONZ, został zrealizowany, z pozytywnym wynikiem, w mieście Siyazan w Azerbejdżanie. Podczas wykonywania takich prac najczęściej stosowany jest agregat sprężarkowy z napędem elektrycznym typu NQK-7/1-5 z dwoma cylindrami oscylacyjnymi. Dokonując oględzin sprężarek trafiających do remontu okazało się, że uszczelnienia w części pneumatycznej oraz elementy grupy cylinder-tłok są całkowicie niesprawne, zęby kół zębatych w części przekładniowej są połamane i zużyte, łożyska zniszczone, a pasy rozerwane itp. Sprężarki kierowane do remontu są prawie zawsze ponownie montowane. W celu poznania przyczyn powstałych usterek, przeprowadzono analizę konstrukcyjno-kinematyczną instalacji sprężarkowej. W tym celu sporządzono schemat kinematyczny mechanizmu przekładniowego sprężarki, czyli mechanizmu korbowo-wodzikowego, metodą zamkniętych konturów z równań projekcyjnych względem osi X i Y, a opierając się na założeniu, że kąty obrotu osi tłoka i cylindra są równe, znaleziono wartości chwilowego kąta obrotu, prędkości kątowej i przyspieszenia kątowego obrotu cylindra oraz chwilowe wartości przemieszczenia, prędkości i przyspieszenia tłoka wewnątrz cylindra. Wykazano, że wyniki analizy kinematycznej i dynamicznej powinny stanowić podstawę przy wyborze przez konstruktora schematu konstrukcyjnego i określaniu wymiarów produktów, co zwykle stwarza największe problemy podczas projektowania mechanizmu.

2

Mass Moment Determination Using Compound Pendulum

Pluta Z., Hryniewicz T.

International Letters of Chemistry, Physics and Astronomy

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2013

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Vol. 3

85-100

EN

This work has been performed to verify the existent knowledge on determination of the mass moment. For the experiment, a compound pendulum was used. The motivation to undertake these studies were experimental results indicating a big discrepancy in mass moments between the values coming from calculations using the definition formula and these obtained from the experiment. In relation to the axial moment the relative error equals 23.6%, whereas regarding the polar moment the error reached 56.4%. Considering the reason of that discrepancy we could find the existent theory not to be adequate. The theory is then considered in view of verifying first the mathematical pendulum and next the physical/ compound pendulum theory. The consideration has been focused on the description of accelerated motion cycle of both pendulums as it was enough to solve the problem. A source differential equation, which serves to solve any quantum phenomena, was used in the study. Then the course of creation of detailed characteristics of the phase of mathematical pendulum accelerated motion is presented as the basis to derive formula on the mass moment of a compound pendulum. At the end this new adequate theory was verified showing the relative error to be less than one per cent.

3

Analysis of diagnostic utility of instantaneous angular speed fluctuation of diesel engine crankshaft

Dereszewski M., Charchalis A., Polanowski S.

Journal of KONES

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2011

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Vol. 18, No. 1

123-128

EN

Frequent crew rotation, a shorthand, and various levels of technical crew skills, are the facts with the ship-owners has to cope very often. Having the proper level of engine exploitation as a main objective is necessary to implement a constant engine monitoring system, in order to obtain quick and reliable diagnostic information. One cannot omit the financial aspect of monitoring system implementation, created by its price and costs of service. In this paper, the analysis of diagnostic utility of the signal deriving from a propulsion shaft fluctuation during its one revolution is presented. The angular speed of the shaft was measured using a laser sensor of torque meter ETNP-10. Diagnostic utility validation has been verified on a basis of combustion quality, in cylinders of two-stroke, turbocharged Marine Diesel Engine. Test was carried out on board of a container vessel during its sea passage. In order to evaluate the effectiveness of the method, the crew simulated engine’s malfunction by fuel injection cut-off in various cylinders (only one in the same time).The interference signals decomposition was carried out using the method of synchronous averaging and moving approximation with polynomial of 3rd exponent.