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1

The possibility of application of the acoustic emission method for monitoring friction processes

Dudzik K., Ziegler B.

Journal of KONES

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2018

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Vol. 25, No. 2

113--119

EN

This article presents the methodology and research results of monitoring friction processes between couple of cooperating elements by acoustic emission method. The research was carried out at the lathing machine test stand of the Technische Hochschule Mittelhessen. The test stand included lathing machine Proxon PD 210, shaft, made of austenitic stainless steel X2CrNi18-9 and steel plate, made of S235. The Friction process was monitored by an acoustic emission set made by Physical Acoustics Corporation (PAC). The PAC system includes: preamplifier USB AE Node, type 1283 with bandpass 20 kHz – 1 MHz, AE signal measurement sensor type VS 150M, with a frequency range 100-450 kHz, computer with AE Win for USB Version E5.30 software. During the study, the acoustic emission (AE) generated by friction between shaft and steel plate was recorded. The load of the plate was 0, 1, 2, 3, 4, 5 and 10 N. The following parameters were determined: amplitude, number of events – hits, the effective value of the signal (RMS). The use of grease between the cooperating elements caused a significant reduction in friction and thus the power of the generated signal (10 to 30 times). In the case of dry friction, without grease, the maximum RMS value was recorded at 4 N load and at the lubricant between the pair cooperating at 1 N load. The research has shown that it is possible to monitor the friction process between cooperating elements using the acoustic emission method.

2

The possibility of application the acoustic emission method for monitoring flow of water within a ball valve

Dudzik K., Ziegler B.

Journal of KONES

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2016

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Vol. 23, No. 4

87--92

EN

Acoustic emission method (AE) can be used for the diagnosis of machine parts or apparatus such as, for example, ball valves. This paper presents the methodology and research results of ball valve in fresh water systems. The opening angle of the valve was changed during the research. The flow of water was measured by a magnetically inductive flowmeter. The research was carried out on a laboratory test stand using an acoustic emission set made by Vallen Inc. This set included: 4 channel signal recorder AMSY 6, two measurement modules ASIP-2/S, preamplifier with a frequency range 20 kHz – 1 MHz and the strengthening of 34 dB and AE signal measurement sensor type VS 150M, with a frequency range 100 – 450kHz. The obtained from the AE-System made by Vallen were compared with the results of the AE-System made by Physical Acoustics (PAC). The PAC system includes preamplifier USB AE Node, type 1283 with bandpass 20 kHz – 1 MHz, AE-Sensor R6D, computer with AE Win for USB Version E5.32 software. During the study, the acoustic emission (AE) generated by flowing water was recorded. The following parameters were determined: amplitude, number of events – hits, the effective value of the signal (RMS). Analysis of the results showed that within a specific range of opening angle of the valve the value of the generated acoustic emission in flowing water increases. This is probably associated with the occurrence of cavitation within the valve. This is an undesirable phenomenon and that these opening angles of ball valve should be avoided in the normal operation.

3

Boundary layer controlin transonic compressor flows

Ziegler B.

Journal of Mechanical and Transport Engineering

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2015

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Vol. 67, No. 3

53--68

EN

This article presents a novel concept for coupled boundary layer control in transonic axial compressors. Proposed control scheme utilizes two steady active methods and couples them creating compact and in principle passive boundary layer control method. Both presented methods (steady suction and steady tangential blowing) are known since many years. In this article they are presented in the context of coupling them on two neighbouring stages. Presented analysis shows that the proposed solution allows for very high stage loadings and pressure ratios. The concept is presented on the set of transonic cascades, where it shows to prevent separation in regions of high adverse pressure gradients (associated both with occurrence of shockwaves and high aerodynamic loading).

PL

W artykule zaprezentowano nowatorską koncepcję sprzężonej kontroli warstwy przyściennej w transonicznych sprężarkach osiowych. Koncepcja ta jest oparta na dwóch znanych metodach aktywnych (stacjonarnym odsysaniu i stycznym nadmuchu), z których utworzono pasywną metodę kontroli warstwy przyściennej. Metoda ta polega na wykorzystaniu strumienia odsysanego z jednego stopnia sprężarki wielostopniowej jako źródła nadmuchu na stopniu poprzednim. Analiza wykazała, że proponowane rozwiązanie pozwala osiągać duże obciążenia i duży spręż stopnia sprężarki osiowej. Koncepcję zaprezentowano na przykładzie przepływów przez dwie transoniczne palisady sprężarkowe – kontrola warstwy przyściennej zapobiega separacji przepływu (zarówno indukowanego faląuderzeniową, jak i związanego ze znacznym obciążeniem aerodynamicznym).

4

Transonic axial compressor active boundary layer control concept and its evaluation

Ziegler B.

Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika

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2014

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z. 86 [290], nr 1

143--150

EN

The article presents a concept of boundary layer control in transonic axial compressors. Two methods for obtaining boundary layer control are presented. It is proposed that by combining those two methods, an efficient way of preventing turbulent boundary layer separation in transonic compressor passages can be obtained without the loss of the compressor flux. The concept, is based on the idea of removing boundary layer flows at one stage, and using this removed flux as a blowing type boundary layer control, at previous stage where lower pressures occur. This creates a loop of secondary flow between those stages preventing the boundary layer separation (especially the shock induced separation) on both stages. Two dimensional numerical analyses are performed to assess the possible passage performance (especially the diffusion factor). On the basis of two dimensional analyses, the possible performance of such compressor stage is estimated. The aerodynamic possibility of greatly increasing the axial compressing stage loadings and pressure ratios without increasing blade velocities and passage flow Mach numbers is shown. This possibility has a growing importance as the overall pressure ratio of turbojet engines and tends to rise with every next engine generation. Main conclusions are drawn, showing the possibilities for further research in the scope of this concept.

PL

Artykuł prezentuje koncepcję dwóch metod kontroli warstwy przyściennej w kanałach transonicznych sprężarek. Zaproponowano aby przez połączenie tych dwóch metod, skuteczny sposób zapobiegania turbulentnego oddzielenia warstwy granicznej w transonicznych kanałach sprężarek można uzyskać bez straty strumienia sprężarki. Koncepcja opiera się na idei usuwania przepływów w warstwie brzegowej w jednym etapie oraz wykorzystaniu strumienia jako kontroli warstwy brzegowej we wcześniejszym etapie, gdy występuje niższe ciśnienie. To tworzy wtórną pętlę przepływu pomiędzy tymi etapami uniemożliwiających rozdzieleniu warstwy granicznej (zwłaszcza rozdzieleniu wywołanemu wstrząsem) na obu etapach. Dwuwymiarowa analiza numeryczna została przeprowadzona w celu oceny możliwej wydajności przejściowej (zwłaszcza współczynnika dyfuzji). Na podstawie dwuwymiarowej analizy określono możliwość wykonania takiego stopnia sprężarki. Przedstawiono aerodynamiczną możliwość znacznego zwiększenia obciążeń stopnia sprężania osiowego i wskaźników ciśnienia bez zwiększania prędkości łopat i liczb Macha podczas przepływu. Możliwośćta ma coraz większe znaczenie jako wskaźnika całkowitego ciśnienia silników turboodrzutowych i wykazuje tendencję do wzrostu w każdej następnej generacji silnika. Nakreślono główne wnioski, pokazując możliwości dalszych badań w tym zakresie.

5

A new measurement method of friction forces regarding slide journal bearings by acoustic emission

Ziegler B., Wierzcholski K., Miszczak A.

Tribologia

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2010

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nr 1

149-156

EN

The present paper describes the new results of measurements performed at University of Applied Sciences Giessen between 2008 and 2009. A new measurement method for the determination of friction conditions within journal slide bearings by using the Acoustic Emission Method is presented. The measurements were taking out using basic oil SN 500. Hardness and roughness of the cooperating surfaces are the same as in the measurements which were presented in papers [L. 4, 5] a year ago. During the measurements the temperature is taken into account. The Acoustic Emission Analysis is (in opposite to the aforementioned friction power measurement) a relative method, which means that the absolute amount of a RMS-Value depends on the measuring chain. The results are compared and discussed with other results obtained during experiments performed at the Maritime University Gdynia.

PL

Niniejsza praca przedstawia nowe rezultaty badań eksperymentalnych związanych z pomiarami sił tarcia w łożyskach ślizgowych metodą emisji akustycznej przeprowadzonych w okresie od 2008 do 2009 roku na Uniwersytecie Nauk Stosowanych w Giessen. Opisane zostały kolejne kroki pomiarów wartości tarcia hydrodynamicznego metodą emisji akustycznej na odpowiednio dostosowanym stanowisku badawczym w Giessen z uwzględnieniem pomiarów w zakresie tarcia mieszanego. W badaniach tych uwidoczniony został wpływ obniżającej się temperatury na wzrost sił tarcia w trakcie eksploatacji łożyska ślizgowego. Twardość i chropowatość współpracujących powierzchni w obecnych badaniach jest identyczna z twardością i chropowatością występującą w poprzednich badaniach, które zostały szczegółowo opisane w pracach [L. 4, 5]. Siły tarcia oraz ich warunki brzegowe zostały szczegółowo pomierzone na stanowisku badawczym dla niewielkich obciążeń. Dokonano pomiaru zależności pomiędzy siłami tarcia a różnymi wartościami liczb Sommerfelda. Podczas pomiarów metodą emisji akustycznej została szczegółowo uwzględniona temperatura. Stroną korzystną metody dokonywanych pomiarów jest fakt, że można pomierzyć absolutne wartości siły tarcia. Pomiar sił tarcia dokonany metodą emisji akustycznej uzewnętrznia zależność pomiędzy wysokimi częstotliwościami oscylacji mierzonych wartości powodowanych przez tarcie hydrodynamiczne pomiędzy molekułami oleju. Korzystną stroną tej metody jest fakt, że oscylacje mogą być wyznaczone bezpośrednio od źródła do czujnika, a ten fakt umożliwia pomiary "online". Analiza emisji akustycznej w przeciwieństwie do pomiarów mocy tarcia wykonywanych na stanowisku badawczym w Akademii Morskiej w Gdyni pokazuje, że wartości pomocnicze RMS wyrażone w mV zależą od kolejności pomiarów. Rezultaty badań wartości sił tarcia zostały przedyskutowane oraz porównane z innymi wartościami uzyskanymi na drodze ekspe- rymentalnej przy wykorzystaniu innego stanowiska badawczego zbudowanego w Akademii Morskiej w Gdyni.

6

A new method of measuring the operating parameters of slide journal bearings by using acoustic emission

Ziegler B., Wierzcholski K., Miszczak A.

Tribologia

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2009

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nr 6

165-174

EN

This paper determines the new results of experimental research due to the hydrodynamic friction forces identification using acoustic emission method The results are connected with the dependences between hydrodynamic friction forces in slide journal bearings, angular velocities of the journal, bearing load and Sommerfeld numbers. These measurements were performed by using the Acoustic Emission Method for basic oil and for Lotos oil on the test stand at Gdynia Maritime University. After Authors knowledge the presented results obtained for basic oil and Lotos oil are similar with the analogous own results which were presented for Castrol oil in papers of the author’s which are published one year ago. The results are discussed and compared with other new results obtained in experiments performed at the University of Applied Sciences Giessen / Germany.

PL

Niniejsza praca przedstawia nowe rezultaty badań doświadczalnych autora, wykonanych na stanowisku badawczym w Akademii Morskiej w Gdyni a dotyczących identyfikacji sił tarcia występujących w tarciu płynnym łożyska ślizgowego metodą emisji akustycznej. Badania te polegają na doświadczalnym wyznaczeniu zależności pomiędzy siłami tarcia występującymi w poprzecznym łożysku ślizgowym podczas jego eksploatacji a prędkością kątową wału łożyskowego, obciążeniem łożyska, a także liczbami Sommerfelda. Takie pomiary zostały przeprowadzone przy wykorzystaniu emisji akustycznej dla oleju bazowego oraz dla oleju Lotos. Według informacji autorów niniejsze rezultaty badań uzyskane dla oleju bazowego oraz dla oleju Lotos są porównywalne z analogicznymi wynikami pomiarów uzyskanych i opublikowanych przez autorów rok temu przy użyciu oleju Castrol. Niniejsze rezultaty badań zostały również porównane z wynikami badań przeprowadzonymi przez autorów w Uniwersytecie Nauk Stosowanych w Giessen w Niemczech.

7

Test stand in university of applied science giessen for friction forces measurements in slide bearing using the acoustic emission method

Ziegler B., Wierzcholski K., Miszczak A.

Journal of KONES

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2008

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Vol. 15, No. 3

591-595

EN

The present paper shows particularly description of the construction of the test stand for experimental research performed in University of Applied Science Giessen and connected with the measurements of hydrodynamic friction forces in journal slide bearings by using the Acoustic Emission Method. The test stand is adapted for the friction force measurements for the low bearing load and for the high bearing load. For such test stand in the case of low and high loads the dependencies between friction forces and time can be exactly obtained. During the measurements the temperature changes are expected. The advantage of this method is the fact that oscillations of measured friction values can be executed directly from the source to the sensor, what enables us to do an "online-measurement". The Acoustic Emission Analysis is (in opposite to the aforementioned Friction Power measurement) a relative method, which means, that the absolute amount of a RMS-Value depends on the measuring chain.

8

Friction forces measurements for slide bearing test stand in maritime university Gdynia using the acoustic emission method

Ziegler B., Wierzcholski K., Miszczak A.

Journal of KONES

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2008

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Vol. 15, No. 2

571-577

EN

The present paper determines the results of experimental research performed in Gdynia Maritime University and connected with the measurements of hydrodynamic friction forces in slide journal slide bearings by using the Acoustic Emission Method. A new method for mechanical friction force measuring was carried out at this test stand, simultaneously the friction force will be indicated by an optimized Acoustic Emission System. The friction conditions at the test were measured by two different methods. At the one hand the friction power measurement and at the other hand the Acoustic Emission Analysis. One characteristic of the friction power measurement is the rather inert reaction to the oscillations of the slide bearing. The advantage of the method is the fact that one can measure absolute values of the friction power. In opposite to that, the Acoustic Emission Analysis measures the high frequency oscillations caused by the hydrodynamic friction between the oil molecules. The advantage of this method is the fact that this oscillations can be executed directly from the source to the sensor, what enables us to do an "online-measurement". The Acoustic Emission Analysis is (in opposite to the aforementioned friction power measurement) a relative method, which means, that the absolute amount of a RMS-Value depends on the measuring chain. The results are compared and discussed with other results obtained in experiments performed in University of Applied Science Giessen.

9

Friction forces measurements by the acoustic emission for slide bearing test stand in uni of applied science Giessen

Ziegler B., Wierzcholski K., Miszczak A.

Journal of KONES

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2008

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Vol. 15, No. 4

627-633

EN

The present paper describes the results of measurements performed in University of Applied Science Giessen and determined hydrodynamic friction forces in journal slide bearings by using the Acoustic Emission Method. It describes the use of the Acoustic Emission Analysis as an indicator of the bearing friction at slide bearings. The investigations were made at two different test stands. The test stand at Maritime University Gdynia covers the hydrodynamic operation range, the test stand at University of Applied Science Giessen the mixed friction area. The successive steps of measurements of the hydrodynamic friction forces are presented in this paper. Hardness and roughness of cooperating surfaces is in this paper particularly described. The friction values and its boundary conditions at the test were measured for the low bearing load and for the high bearing load. In both cases, the dependencies between friction forces and time are exactly obtained. During the measurements, the temperature is taken into account. The advantage of this method is the fact that these oscillations can be executed directly from the source to the sensor, what enables us to do an "online-measurement". The Acoustic Emission Analysis is (in opposite to the aforementioned friction power measurement) a relative method, which means, that the absolute amount of a RMS-Value depends on the measuring chain. The results are compared and discussed with other results obtained in experiments performed in Maritime University Gdynia.

10

Contribution of acoustic emission into optimal bearing lubrication

Ziegler B.

Journal of KONES

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2007

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Vol. 14, No. 4

571-578

EN

This article describes the bases of the acoustic emission analysis to make successful applications in the range of the tribological problems, especially at machinery slide journal bearings. Acoustic emission differs from ultrasonic testing, which actively probes the structure; Acoustic emission listens for emissions from active defects and is very sensitive to defect activity when a structure is loaded beyond its service load. During detecting and analysing the generated acoustic emission we earn information about the behaviour, state or quality of these acoustic emission sources. A lot of different sources are generating acoustic emission (e.g. corrosion processes, fluid friction, cracks, cutting processes). This paper shows the acoustic emission sources, the wave propagation, the mode conversion, the damping, the design of a typical transducer and the whole measurement chain. The piezoelectric disc, the "heart" of a typical acoustic emission transducer, converts the incoming mechanical wave into a corresponding electrical signal. Every transducer has its own characteristic, if this is unknown we can test it with difficult methods e.g. so called reciprocal method. On the end of this paper the signal parameters (burst-count, rise-time, signal-duration, signal peak amplitude, signal energy and root-mean-square) will be discussed.

11

Acoustic emission as friction force indicator after test stands experiments

Ziegler B., Miszczak A.

Journal of KONES

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2007

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Vol. 14, No. 4

579-586

EN

This paper describes the use of acoustic emission measurement as an indicator of friction force into hydrodynamic journal bearings. The parameters load, speed, friction force, oil-temperature as well as the displacement of the sleeve are mainly measured in mutual dependence in journal plain bearing test stands. The friction force can not be measured directly, it must be calculated from the reaction force of the sleeve. Many different constructions are in use with the aim to load the bearing with a minimized influence of friction force measurement. Because of the huge influence to the friction force it is desirable to have parameters that are corresponding with it and are independent of the bearing load. We investigate the applicability of the acoustic emission analysis to indicate the friction force at an existing plain bearing test stand. The adoption of the acoustic emission measurement system (the diversion of the waves from the sleeve, the wave propagation through the AE transducer, the measurement chain and the damping of the mechanical and electrical disturbance) onto the test stand is described.