Wyniki wyszukiwania - BazTech

1

Failure analysis of a high-speed induction machine driven by a SiC-inverter and operating on a common shaft with a high-speed generator

Breńkacz Łukasz, Bagiński Paweł, Adamowicz Marek, Giziewski Sebastian

Eksploatacja i Niezawodność

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2022

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Vol. 24, no. 1

177--185

EN

Due to ongoing research work, a prototype test rig for testing high speed motors/generators has been developed. Its design is quite unique as the two high speed machines share a single shaft with no support bearings between them. A very high maximum operating speed, up to 80,000 rpm, was required. Because of the need to minimise vibration during operation at very high rotational speeds, rolling bearings were used. To eliminate the influence of higher harmonics of supply voltage and current on the formation of torque oscillations on the shaft and excessive losses in the form of heat, a voltage source inverter with high switching silicon carbide (SiC) power transistors characterizing high precision of the output voltage generation with a fundamental harmonic frequency of several kilohertz has been used. During the first start-ups, it turned out that the system was not stable, and a failure occurred. The paper presents the consequences that may arise when a machine operating at a speed of about 70,000 rpm fails. The article contains pictures of a generator failure that occurred at a high rotational speed.

2

Vibration analysis of a turbocharger with an additively manufactured compressor wheel

Andrearczyk Artur, Bagiński Paweł

Zeszyty Naukowe. Transport / Politechnika Śląska

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2020

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z. 107

05--17

EN

This article presents the vibration analysis of a turbocharger, whose compression wheel was manufactured using a high-precision additive manufacturing technology. Currently, there are advance studies around the world for the development of parts of innovative fluid-flow machines using additive manufacturing techniques. The experimental research was carried out under conditions of reduced flow temperatures. The tests and the analysis were performed on a wheel manufactured using a 3D printing technology and on a conventionally used aluminium wheel. Apart from an FFT analysis of the vibration signal during machine operation, a machine run-up test was conducted (up to a speed of 105,000 rpm). The results showed the positive impact of the use of a plastic wheel on the dynamics of the system at a certain speed range, which might contribute to the development of a new method to optimise the geometry of flow systems in small high-speed turbomachines. A modified automotive turbocharger was subjected to experiments on a test stand.

3

The Use of Additive Manufacturing Technology to Manufacture Slide Bearing Sleeves – a Preliminary Study

Andrearczyk Artur, Bagiński Paweł

Tribologia

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2020

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nr 3

7--14

EN

The paper presents the application of an unconventional method of manufacturing bearing sleeves as well as the carrying out of preliminary research in which the manufactured components were used on a real object. Additive manufacturing methods are increasingly being used, which leads to the rapid development of technologies and their applications. The MultiJet Printing technology was used in the research, which allows precise 3D printing of sleeves made of polymeric materials. The first part of the article deals with the selected manufacturing method and the preparation of a model. The study aimed at evaluating the usefulness of bearings manufactured using the 3D printing technology to support slow-speed rotors. The preliminary research described focuses on the study of operating parameters such as the moment of friction and the bearing node temperature as a function of rotational speed during operation. Experimental tests were carried out at low rotational speeds. This paper presents and determines the scope of the application of bearings manufactured using 3D printing technology.

PL

W pracy przedstawiono zastosowanie niekonwencjonalnej metody wytwarzania panwi łożysk wraz z przeprowadzeniem badań wstępnych z użyciem wykonanych elementów na obiekcie rzeczywistym. Metody wytwarzania addytywnego stosowane są na coraz większą skalę, co wiąże się ze znacznym rozwojem technologii i ich aplikacjami. Do badań wykorzystano technologię MultiJet Printing, pozwalającą na precyzyjny wydruk 3D panwi z materiałów polimerowych. Pierwsza część pracy poświęcona jest wybranej metodzie wytwarzania i przygotowaniu modelu. Celem pracy było określenie przydatności łożysk wykonanych technologią wydruku 3D do podparcia wolnoobrotowych wirników. Opisywane badania wstępne obejmują poznanie takich parametrów pracy jak moment tarcia oraz temperatura węzła łożyskowego w funkcji prędkości obrotowej podczas pracy. Część eksperymentalną przeprowadzono w warunkach niskich prędkości obrotowych. W niniejszej pracy przedstawiono i określono zakres zastosowań łożysk wytworzonych omawianą w artykule metodą wydruku 3D.

4

Research of the Influence of Long-Lasting Cyclic Loading on the Geometry of the Bump Foil of a Gas Foil Bearing

Bagiński Paweł, Żywica Grzegorz

Tribologia

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2019

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nr 2

5--13

EN

The article describes the research aimed at checking the effect of a long-lasting pulsating load on the geometry of the bump foil of a foil bearing. The tested foil was made of Inconel 625, which is one of the most popular alloys used to manufacture components of foil bearings. The foil was tested both before and after its heat treating in an electric furnace. The foil was subjected to loading using an electromagnetic vibration exciter, whose exciting force and frequency were appropriately selected. The height of the individual bumps of the foil was the basic parameter controlled after each measurement series. In addition, wear of the foil at the contact points with the plates of the test rig was checked. The materials of which the elements of the tested system were made are the same as the ones used in a real bearing. The article presents graphs that show how the geometry of the bump foil changed during the research. The wear of the elements mating with the bump foil was also evaluated.

PL

W artykule opisano badania, których celem było sprawdzenie wpływu długotrwałego obciążenia tętniącego na geometrię folii podpierającej łożyska foliowego. Testom poddano folię wykonaną z jednego z najbardziej popularnych stopów stosowanych na elementy łożysk foliowych (Inconel 625). Najpierw badano ją w stanie surowym, a następnie po wygrzaniu jej w piecu. Obciążanie badanej folii było realizowane za pomocą elektromagnetycznego wzbudnika drgań, który pracował z dobraną siłą i częstotliwością. Podstawowym parametrem, który był kontrolowany po każdej serii pomiarowej, była sztywność poszczególnych wypukłości folii. Dodatkowo sprawdzano zużycie folii w miejscach jej styku z płytami stanowiska badawczego. Materiały, z których wykonane były elementy badanego układu, zostały dobrane tak, jak w rzeczywistym łożysku. W artykule przedstawiono charakterystyki, które opisują zmianę geometrii folii falistej w czasie badań. Oceniono także zużycie elementów współpracujących z folią podpierającą.

5

Investigation of gas foil bearings with an adaptive and non-linear structure

Żywica Grzegorz, Bagiński Paweł

Acta Mechanica et Automatica

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2019

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Vol. 13, no. 1

5--10

EN

The article discusses the results of simulation-based and experimental research carried out on gas foil bearings. Owing to the use of a set of flexible thin foils in such bearings, they exhibit certain beneficial features that cannot be found in other types of bearings. They have nonlinear operational characteristics and allow the dissipation of excess energy, thus reducing the vibration level. Moreover, gas foil bearings can self-adapt themselves to the current operating conditions by changing the shape of the lubrication gap. Therefore, they can be used to improve the dynamic performance of rotors, in particular, those operating at very high rotational speeds. This article explains the mechanisms for changes of stiffness and vibration damping in compliant components of a foil bearing. The results of the analysis of the bearing’s subassemblies using advanced numerical models are presented. They are followed by conclusions that were drawn not only from these results but also from the results of the experimental research. It has been proven that the rotor supported on carefully designed foil bearings is capable of maintaining a low vibration level, even if it operates at a high rotational speed.