Modeling and diagnostics of vertical axis rotary system driven by multi gear drive

R & D work related to the technical condition assessment and unexpected failure prevention of the bearings and gearings of vertical rotor system, characterized by particularly large dimensions and mass. Theoretical studies are based on the gear meshing modeling in terms of determined contact stresses. Experiments were carried out by measuring the rotors displacements and vibrations amplitudes, as well as measuring absolute vibrations of bearings. On the basis of experimental and theoretical studies defects on contact surfaces of the gear teeth were determined. Theoretical model of gear’s teeth contacting was created and solved by finite element method. The theoretical model enables to assess the disadvantages of vertical gearing teeth contacting process in terms of defected powered gear bearings and to predict development mechanism of defect in order to avoid unexpected failures

The comparison of diagnostic features between the vertical and horizontal axis rotors

The development of modern rotating machines requires design of effective defect diagnostics methods for evaluation of technical conditions not only for the entire rotating system, but for each damaged element, e.g. journal and antifriction bearings, couplings, gears, etc. Optimization of rotating system goes through theoretical modeling based on FEM, bond graph theory, prototyping and experimental vibration testing rotating kits in labs and machines in situ. Nodal defects must be observed in early stage of their development. This article presents faults diagnostic for the vertically and horizontally oriented rotor rolling bearings. Studies were carried out at the original research setup. The research stand is composed of a rotor with a disc with the excitation mass fixed on it, rotor, driven by asynchronous AC motor controlled by frequency inverter. Rotor mounted in supports using single row deep groove ball bearings SKF 6004 – 2Z, class C3. During the research, the second non defected rolling bearing was replaced with rolling bearing with inner and outer ring race defects. Experiments were performed by changing the rotor axis of rotation from vertical to horizontal. Experiments were carried out with permissible imbalance (according to ISO 1940-1) and with more than 2 times higher than permissible, assessing the level of allowable imbalance magnitude, according to standard G6.3 class for rotary systems with flywheel impeller. Measurements of mechanical vibration acceleration are taken with 4 acceleration transducers, mounted on each of the supports. This article is focused on analyzing the second support y direction (gravity direction) transducer data: velocity spectrums, waterfall plots and cascades. Analysis of horizontally and vertically oriented rotor dynamics, characteristics of diagnostics and statistical analysis of measurement data was performed. New statistical parameter, “Defect visibility ratio (DVR)” was presented. This parameter helps in quantifiably assessing the influence of excitation characteristics of differently oriented rotors to dynamics diagnostics. The statements listed in conclusions are formulated according to results obtained during experiments only

Diagnostic research of rotor systems with variable inertia moment

The main reason of a breakdown for bearings, operating in rotor systems with dynamic loads, is rotor unbalance causing heavy loads especially during the rotational resonance speeds at run ups and coast downs when operation speed of a rotor system exceeds the resonance speed. Dynamic loads of rotor systems with rotor variable inertia moment affecting bearings, when the rotor‘s rotation speed is constant as well as during the run up and coast down periods, are significantly lower in comparison to instant inertia moment rotors. Experimental research of a flexible rotor with variable inertia moment performed by measuring rotor’s vibration displacements with proximity probes at large rotation speed interval exceeding resonance. The analysis of results allowed determining the optimal acceleration-deceleration modes and variable dynamic stiffness of rotating system. Experimental research has been carried out with an original rotor system testing facility and a high speed multi-channel vibration signal analyzer unit

Modeling and simulation of variable inertia rotor

This article presents experimental and theoretical research of a rotor system with variable inertia moment. A mechanical system model was designed using SimMechanics toolbox in Matlab Simulink. Experimental and simulation results of the test rig are presented in the article. In order to compare the obtained results, model parameters were chosen based on actual parameters of the test rig. Results obtained from the analysis of the developed dynamic model enable to propose a rotor design with a variable inertia moment which, under certain initial conditions, would maximally reduce forces exerted on bearings during the operation

Modeling and simulation of variable inertia rotor

This article presents experimental and theoretical research of a rotor system with variable inertia moment. A mechanical system model was designed using SimMechanics toolbox in Matlab Simulink. Experimental and simulation results of the test rig are presented in the article. In order to compare the obtained results, model parameters were chosen based on actual parameters of the test rig. Results obtained from the analysis of the developed dynamic model enable to propose a rotor design with a variable inertia moment which, under certain initial conditions, would maximally reduce forces exerted on bearings during the operation

VIDAUS DEGIMO VARIKLIŲ VIRPESIŲ TYRIMŲ SPECIFIKA IR PROBLEMATIKA

Vibration investigation and defects’ diagnostics of variety industrial machinery (the technical condition evaluation, identification ofdefects and protection against unexpected failures) are increasingly being applied in practice in nowadays. These diagnostic investigationsare inevitably related to the desire to ensure reliability of the machinery. Meanwhile, the vibration investigations of the internalcombustion engine are carried out very rarely, because they are very complex and difficult. Therefore, this article provides vibrationinvestigation and the specifics of the problems of a high-power internal combustion engines and gives practical examples ofvibration measurement. In the article is provided the comparative vibration investigation example of the electric motor in order tobetter understand the differences of the internal combustion engine diagnostic investigation.KEYWORDS: internal combustion engines, electro motors, vibration analysis, technical condition evaluation, defects’ diagnostic

Investigation of pressure pulsations in centrifugal pump system

This article presents the results obtained on vibration measurements of the centrifugal pumps together with the measurements of pressure pulsations, generated in the pipeline system. The main task of the current investigation, developed based on previously conducted substantiated experimental investigations, is to identify the main source of pressure pulsations in the pipeline system. More than 9 different operating modes were set for high capacity (up to 1000 m3/h) centrifugal pumps during the vibration and pressure pulsation measurement processes. Throughout the measurements, the high capacity pumps, connected in series or parallel, were transferring fluids to a pipeline, in a length of more than 350 meters. Having conducted the experimental investigation, the main source of pressure pulsations, generated in the pipeline system, was identified

VERTIKALIŲ ROTORINIŲ MAŠINŲ DIAGNOSTIKOS SPECIFIKA JŪRINIAME TRANSPORTE

Theory and experiment – based diagnostic research of industrial machines is widely conducted by researchers and scientists of Lithuanianand foreign universities as well as scientific research institutes complying with measured parameters of vibrations, caused byrunning machines. Researchers focus on assessment of technical condition of the industrial machines themselves, diagnostic of defects,and implementation of preventive measures for unexpected breakdowns. However, a majority of conducted diagnostic researchis related to machinery, mounted onshore, having a solid and rigid foundation structure, which does not cause any issues, pertainingto vibration damping, and decrease in level of vibration or vibration interference. As revealed by the practical experimental research,conducted by the scientists of this group in the sea – going vessels, vibration diagnostic research is far more complicated andcomplex, as majority of various ship machinery is mounted on the same foundation structure. For this reason, the aim of the presentresearch is to design a smart acceleration transducers signal identification algorithm intended for mechanical vibrations, which wouldallows to use of acceleration transducers in monitoring systems of rotor machines, having a common foundation structure.Experimental research carried out on a marine transport under actual working conditions using modern vibration research equipmentand analyzing research data using specialized software. Acquired experience will be used during a course of studies as well as infuture continuing with the initiated research. The designed algorithm for mechanical vibration signal identification will be installed insmart monitoring equipment, which, with the help of IT and electronic engineers, will be developed having received an additional orparallel financing. Research data will also be used to design systemsof combined damping.KEY WORDS: rotor dynamics, diagnostics, vertical rotors, rotor systems with shared foundation

LAIVO VAROMOSIOS SISTEMOS REDUKTORIAUS IR VELENO LINIJOS VIRPESIŲ TYRIMAS

The main part of the ship, which ensures the movement of the ship is the ship's propulsion system. A typical ship's propulsion system consistsof a main engine, gearbox and propellers shaft line. Typically on ships are not installed permanent vibration monitoring systems Typicallyon ships are not installed permanent vibration monitoring system, there are installed only the bearing oil temperature, pressure, shaftspeeds, the powers of diesel engine continuous measurement systems. Therefore, to ensure the reliability and safety of the ship's propulsionsystem the monitoring of technical condition based on the vibration signals measurements is highly recommended. In this paper are investigatedship's propulsion systems gearbox and shaft line vibration and identified the main sources of vibration. Experimental of vibrationsmeasurements are performed when ship moves at sea from one port to another at its normal loading.KEYWORDS: The ship's propulsion system, gearbox, shaft line, vibration measurement, diagnostics, maritime transpor

KINATAMO MASĖS INERCIJOS MOMENTO ROTORINĖS SISTEMOS TYRIMAI

This article present experimental and theoretical studies of variable mass moment of inertia rotor system. The mechanical model ofthe system was developed by using Matlab Simulink Simmechanics software. The experiment and simulation results are comparedand presented in this article. For Validation of Model, parameters were chosen adequately to test rig according real test rig parameters.Based on the dynamic model and experimental comparisons, can be said that the model complies with the experimental test rig,and it can be used for research of variable mass moment inertia rotor systems.KEY WORDS: Variable moment of inertia, modelling, diagnostic