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1

Metoda wyznaczania stałej czasowej termopary na podstawie pomiaru szybkozmiennej temperatury spalin wylotowych silnika o ZS

Puzdrowska P.

Zeszyty Naukowe Akademii Morskiej w Gdyni

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2018

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nr 108

115--133

PL

W niniejszym artykule przedstawiono problematykę wyznaczania stałej czasowej termopary. Wskazano na wagę właściwości dynamicznych termopar podczas eksperymentów. Przedstawiono stanowisko laboratoryjne, na którym przeprowadzono badania, mające na celu wyznaczenie stałych czasowych dwóch rodzajów termopar. Zaprezentowano trzy metody obliczania tego parametru. Określono wartość stałej czasowej, wyznaczonej metodą symulacji numerycznej wymiany ciepła między spoiną termopary a spalinami ją otaczającymi, przy założeniu wolnozmienności procesu, czyli przejścia z jednego stanu ustalonego do drugiego. W kolejnym kroku obliczono ten parametr również dla takiego przejścia, jednak dokonano tego na podstawie rzeczywistej szybkozmiennej temperatury spalin, zarejestrowanej podczas badania na stanowisku laboratoryjnym. Jako trzecią metodę przedstawiono określanie wartości stałej czasowej dla warunków chwilowych, dla szybkozmiennej temperatury rejestrowanej podczas eksperymentu, dla przebiegu pseudookresowego w obrębie trwania jednego cyklu roboczego silnika. Dokonano porównania i oceny uzyskanych wyników obliczeń, a co za tym idzie, użyteczności metody wyznaczania stałej czasowej termopar.

EN

The article presents issue of determining the time constant of thermocouple. The importance of dynamic properties of thermocouples during experiments was indicated. This paper presents the laboratory stand where experiments were made to determine the time constants of two types of thermocouples. Three methods of calculating this parameter were presented. The value of the time constant was determined by the numerical simulation of heat transfer between thermocouple’s weld and the surrounding exhaust gases, assuming the slow – changing of the process, namely transition from the steady state to the other. In the next step this parameter was calculated for the same transition but it was based on real and quick – changing temperature of exhaust gases, recorded during the experiment on laboratory stand. As the third method there was shown determining the value of time constant for the temporary conditions, for quick – changing temperature, recorded during the experiment, for the pseudo-periodic process within the duration of the cycle of engine. At the end, a comparison and evaluation of the calculation results was made, and the usefulness of the method of determining the time constant of thermocouples.

2

Wykorzystanie metody linearyzacyjnej do wyznaczania stałych czasowych modeli łuku elektrycznego z wymuszeniem prądowym prostokątnym

Sawicki A., Haltof M.

Przegląd Elektrotechniczny

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2017

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R. 93, nr 4

99--103

PL

Opisano trudności w eksperymentalnym wyznaczaniu stałych czasowych modeli matematycznych łuku elektrycznego. Rozważono przebiegi napięcia w obwodzie z wymuszeniem prądowym prostokątnym i modelem Pentegowa łuku. Zastosowano metodę linearyzacyjną do wyznaczania stałych czasowych uproszczonych modeli liniowych, stanowiących szczególne przypadki modelu Pentegowa. Na podstawie symulacji komputerowych procesów w obwodzie z parametrami modeli, wskazano na możliwość stosunkowo dokładnego wyznaczania stałych czasowych tych modeli.

EN

Difficulties in experimental determination of time constants of electric arc models were described. There have been taken under consideration voltage time series in circuit with forced rectangular current and the Pentegov arc model. The linearization method was applied for obtaining time constants of simplified linear arc models which are the particular variants of the Pentegov model. On the basis of computer simulations of processes in circuit with model parameters, it was indicated the possibility of a relatively precise determination of the time constants of these models.

3

The analysis of thermocouple time constants as a function of fluid velocity

Majdak M., Jaremkiewicz M.

Measurement Automation Monitoring

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2016

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Vol. 62, No. 9

284--287

EN

In steady-state conditions when the fluid temperature is constant, there is no damping and time lag so the temperature measurement can be performed with a high accuracy. But when the fluid temperature is varying rapidly as during the start-up, quite appreciable differences occur between the exact and measured temperature because of the time required for the transfer of heat to the thermocouple placed inside a thermometer pocket. The temperature of the fluid is one of the key parameters affecting the proper operation of thermodynamic cycles, so the precise determination of its value is very important. The speed of the response of control systems to a temperature change is closely related to the time constant of the used thermocouples. The paper presents a significant impact of fluid velocity changes (in this case air) on the value of time constants of thermometers. For this purpose, the experimental study was carried out using sheathed thermometers with different diameters and hot junctions. The time constants determined for various thermometers are compared.

4

Analysis of dynamic properties of flat plate and heat pipe solar collectors

Obstawski P., Bakoń T., Tulej M.

Measurement Automation Monitoring

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2016

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Vol. 62, No. 3

105--108

EN

The paper presents an analysis of dynamic properties of two flat plate solar collectors differing in the design of coil and vacuum tube liquid-vapour (heat-pipe) collector. The collector identification experiment was carried out under field conditions based on the methodology described in PN-EN ISO 9806: 2014-2 standard. The results of the field experiment were compared with those obtained under laboratory conditions.

5

Metoda wyznaczania parametrów modelu Pentegowa opisującego łuk elektryczny o charakterystyce statycznej typu Ayrton

Sawicki A., Haltof M.

Przegląd Elektrotechniczny

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2015

|

R. 91, nr 5

117-120

PL

Opisano podstawowe trudności modelowania łuków elektrycznych w szerokim zakresie amplitud wymuszeń prądowych. W celu ich pokonania zaproponowano wykorzystanie modelu matematycznego Pentegowa łuku z charakterystyką statyczną podaną przez Ayrton. Opisano sposób eksperymentalnego wyznaczania parametrów modelu z wymuszeniem sinusoidalnym. Zbudowano makromodel łuku w programie MATLABSimulink i drogą symulacyjną sprawdzono poprawność „metody trzech pomiarów”. Ponadto zbadano jej odporność na zakłócenia działające w obwodzie zasilającym.

EN

Fundamental difficulties in modeling of electrical arcs in wide range of current enforcement amplitudes have been described. To overcome it, usage of Pentegov mathematical model with characteristics provided by Ayrton has been proposed. A method for experimental parameters determination of model with sinusoidal enforcement has been described. Arc macromodel has been built in MATLAB-Simulink application and correctness of "three measurements method" has been checked using simulation. Its tolerance for noise in supply circuit has also been researched.

6

Zmienność stałej czasowej w czasie pomiaru czujnikiem pneumatycznym

Rucki M.

Mechanik

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2015

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R. 88, nr 3CD

228--237

PL

Pomiar bezstykowy czujnikami pneumatycznymi wciąż znajduje zastosowanie w przemyśle, głównie w układach kontroli czynnej. W tych warunkach bardzo istotne są ich właściwości dynamiczne, zależne od geometrii elementów przepływowych oraz od aktualnego ciśnienia w komorze pomiarowej. Badania wykazały, że przy mniejszych ciśnieniach odpowiadających szerszym szczelinom pomiarowym, stała czasowa wzrasta, w niektórych przypadkach nawet o 100%. Nieuwzględnienie tego faktu może doprowadzić do zwiększenia błędów pomiaru właśnie w końcowej fazie obróbki.

EN

Non-contact measurement with the air gauges still takes place in industry, mainly in the in-process inspection. In such work conditions, their dynamic characteristics shaped by geometry of the air gauge and dependent on the actual measuring pressure become of great importance. The investigations proved that when the pressure in the chamber is lower, which corresponds with larger measured slots, the time constant increases, sometimes even up to 100%. If this phenomenon is neglected, the final stage of the machining could bear much larger error than expected.

7

Method for Determining the Parameters of the Pentegov Model Describing an Electric Arc with Hyperbolic-Linear Static Characteristic

Sawicki A., Haltof M.

Biuletyn Instytutu Spawalnictwa w Gliwicach

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2015

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Vol. 59, No. 3

55--60

EN

The article presents reasons for nonlinear static voltage-current characteristics of an electric arc; the characteristics consist of an initial voltage drop followed by a voltage rise in the range of strong currents. The article suggests that overcoming difficulties in mathematical modelling of electric processes in circuits with arcs requires the use of Pentegov assumptions and the building of an arc model utilising a static hyperbolic-linear characteristic. The article also presents a method for the experimental determination of arc model parameters with sinusoidal excitation as well as describes a macromodel built using the MATLAB-Simulink programme. The correctness of analytical expressions specifying mathematical model parameters was verified through simulation. The study also involved testing the resistance of the proposed method to arc length random disturbances.

PL

Opisano przyczyny występowania nieliniowości charakterystyk statycznych napięciowo-prądowych łuku elektrycznego, polegających na ich początkowym opadaniu, a następnie narastaniu napięcia w zakresie silnych prądów. W celu pokonania trudności matematycznego odwzorowania procesów elektrycznych w obwodach z łukami, zaproponowano wykorzystanie założeń Pentegowa i budowę modelu łuku wykorzystującego charakterystykę statyczną hiperboliczno-liniową. Opisano sposób eksperymentalnego wyznaczania parametrów modelu łuku z wymuszeniem sinusoidalnym. Zbudowano makromodel łuku w programie MATLAB-Simulink i drogą symulacyjną sprawdzono poprawność wyrażeń analitycznych określających parametry modelu matematycznego. Ponadto, zbadano odporność proponowanej metody na działające zaburzenia losowe długości łuku.

8

Analytical description of the functioning of electromagnetic pulser of pairwise action

Lavryk Yu., Nishchenko I.

ECONTECHMOD : An International Quarterly Journal on Economics of Technology and Modelling Processes

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2014

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Vol. 3, No 4

17--22

PL

The article analyses the distribution of forces in statical equilibrium on the example of electromagnetic pulser of pairwise action. It views specifications of two stable states of equilibrium corresponding to the cycles of sucking and compression in the operation of the milking unit. The research suggests the way of determining durations of transition states of a pulser which directly impacts the quantities of technical characteristics of a milking unit and the nature of machine milking of cows.

9

Testing the Effect of Column Length Disturbances on the Method used for Determining the Pentegov Model Describing the Electric Arc of the Ayrton Type Static Characteristics

Sawicki A., Haltof M.

Biuletyn Instytutu Spawalnictwa w Gliwicach

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2014

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Vol. 58, No. 6

39--44

EN

The research involved the determination of physical factors affecting the generation of arc column length disturbances in electrotechnological devices. The article contains a justification related to the selection of the Pentegov model for representing the dynamic characteristics of a sinusoidal current powered arc. The research also included the modification of the Ayrton formula approximating static voltage-current characteristics by taking into consideration arc column length random disturbances as well as the development of an arc macro-model and simulations of processes in a simple circuit using MATLAB-Simulink software. The research demonstrated the efficiency of the three measurement method for determining the Pentegov model parameters in conditions arc column length disturbances.

PL

Określono czynniki fizyczne wpływające na powstawanie zaburzeń długości kolumny łukowej w urządzeniach elektrotechnologicznych. Podano uzasadnienie wyboru modelu Pentegowa do odwzorowania charakterystyk dynamicznych łuku zasilanego prądem sinusoidalnym. Dokonano modyfikacji wzoru Ayrton, aproksymującego charkterystyki napięciowo-pradowe statyczne, przez uwzględnie zaburzeń losowych długości kolumny łukowej. Zbudowano makromodelel łuku i wykonano symulacje procesów w prostym obwodzie z wykorzystaniem programu MATLAB-Simulink. Wykazano efektywność metody trzech pomiarów wyznaczania parametrów modelu Pentegowa w warunkach występowania zaburzeń długości kolumny łukowej.

10

Influence of quasi-static gas pressure changes on electric arc modelling in electrotechnological devices

Sawicki A.

Biuletyn Instytutu Spawalnictwa w Gliwicach

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2014

|

Vol. 58, No. 2

39--49

EN

The article presents exemplary applications of devices with electric arc in gases of varying pressure used in industry practice and variants of the approximation of static arc characteristics. The article also contains an analysis of the influence of pressure changes on an arc damping factor function and presents mathematical arc models with a quasi-statically variable pressure parameter. The tests also involved simulations of processes in a simple circuit with an arc. The article also contains the results of calculations in the form of the evolution of dynamic voltage-current arc characteristics influenced by pressure changes.

PL

Podano przykłady zastosowania w praktyce przemysłowej urządzeń z łukiem elektrycznym w gazach o różnym ciśnieniu. Przedstawiono różne warianty aproksymacji charakterystyk statycznych łuku. Przeanalizowano wpływ zmian ciśnienia na funkcję współczynnika tłumienia łuku. Opracowano modele matematyczne łuku z quasi-statycznie zmiennym parametrem, jakim jest ciśnienie. Wykonano symulacje procesów w prostym obwodzie elektrycznym z łukiem. Zaprezentowano wyniki obliczeń w postaci ewolucji charakterystyk dynamicznych napięciowo-prądowych łuku pod wpływem zmian ciśnienia.

11

Damping Factor Function in AC Electric Arc Models. Part. 4. Criteria for Selection of Arc Models and Determination of Low-current Arc Time Constant

Sawicki A., Haltof M.

Biuletyn Instytutu Spawalnictwa w Gliwicach

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2014

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Vol. 58, No. 3

46--55

EN

Causes of problems in strict classification of arcs into two categories: low and high current have been described. Assumption has been taken that processes in column can be approximated with one of two models: Mayr or Cassie. A new criterion of arc classification has been proposed, based on minimal deviation of harmonic relation of real voltage on arc column comparing to theoretically estimated data. Using MATLAB-Simulink program, errors in determining time constant value have been analyzed in Mayr model of arc described with different mathematical models with and without random noise.

PL

Opisano przyczyny trudności w ścisłej klasyfikacji łuków na dwa rodzaje słabo- i silnoprądowe. Przyjęto, że procesy w kolumnie mogą być aproksymowane jednym z dwóch modeli albo Mayra, albo Cassiego. Zaproponowano nowe kryterium klasyfikacji łuków. Za jego podstawę uznano minimalne odchylenia relacji harmonicznych rzeczywistego napięcia na kolumnie łukowej od danych przewidzianych teoretycznie. Na podstawie przeprowadzonych symulacji w programie MATLAB-Simulink przeanalizowano błędy wyznaczania wartości stałej czasowej modelu Mayra łuków opisanych różnymi modelami matematycznymi bez i w obecności zakłóceń losowych.

12

Analysis of chromite processing plant data by first order autoregressive model

Tasdemir A.

Physicochemical Problems of Mineral Processing

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2013

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Vol. 49, iss. 1

157--174

EN

Many mineral processing data can be monitored by a time series model. This research presents results of analysis and simulations of a chromite processing plant data determined by time series model. The plant data obtained by shift to shift include feed grade, concentrate grade, tailing grade, Cr/Fe ratio in concentrate. All the chromite processing data were found stationary over time. The autocorrelation was high for feed grade and Cr/Fe ratio. Weaker autocorrelation was observed for concentrate grade and tailing grade. Autoregressive integrated moving average (ARIMA, 1,0,0) or first order autoregressive (AR, 1) model, was found to fit all data very well. The models obtained have been also shown to be used for the near future estimation of these data. The time constant which is an indicator of sampling frequency of the data sets were determined. It was found that sampling frequency was enough for concentrate and tailing grade and their original values can be used in process control charts for monitoring. On the other hand, the sampling frequency should be reduced for feeding grade and Cr/Fe ratio for the same aims hence ARIMA residual charts were more suitable to monitor their values.

13

Vertical Fall of a Body Under Free Motion

Pluta Z., Hryniewicz T.

International Letters of Chemistry, Physics and Astronomy

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2013

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Vol. 4

56-72

EN

The paper aims at the kinetics of a body under free fall, especially free body motion, the motion occurring in the Earth environs space, that is in the range of the gravity action. A new adequate theory of such a motion, opening new not known kinetic magnitudes, has been elaborated. This theory has its source, which is the dependence of the way length on time. That is the way characteristics created in this work. The worked out theory has been verified by experiment, referred to two different realities. One of them was the body motion in the air environment of the Earth environs space, with the second one occurring in a determined machining space-time. The adequate earth acceleration/gravity has been calculated taking advantage of the theory elaborated; and its value, as indicated, is equal 3.85 mźs-2. Two kinds of accelerations have been separated: inertial and gravitational. The relations occurring between their values on the neighbouring potential fields, unstable, and stable, have been discovered. That discovery indicates on the existence of quantum nature of gravitation.

14

Quantum Nature of Vehicle Motion

Pluta Z., Hryniewicz T.

International Letters of Chemistry, Physics and Astronomy

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2013

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Vol. 8, iss. 1

37--48

EN

The paper presents a new adequate look on the character of motion of any material body, such as moving vehicle. It has been proved, that motion of material bodies has a quantum character. Due to this their consecutive energetic states are obtained by a jump. The phenomenon of quantum in the reference to vehicle kinetics has been derived by indicating its place on the background of characteristics of whole mechanics. The length of vehicle way in particular phases of its motion is that source characteristics the derivatives of which form the development of motion description of a material solid/body. It has been indicated that the quantum nature of body motion does not depend on its magnitude. Thus, as has been noticed, there is an analogy between the macro-body motion and electron motion which change its energy also by jump, by getting from one orbit (energetic level) to another.

15

On the Groundless Use of Mathematics Concerning the d’Alembert’s Rule

Pluta Z., Hryniewicz T.

International Letters of Chemistry, Physics and Astronomy

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2013

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Vol. 7, iss. 2

85--101

EN

The paper discusses the groundless use of mathematics. This question has been explained mainly based on example of the so called d`Alembert’s rule which unfortunately still functions in science none the less it has been based on a fiction, contrary to the truth cognition as the fundamental purpose of science. That pejorative feature of the mentioned paradigm is marked very clearly in the paper to evaluate it negatively as the only one possible note. Next the adequate characteristics of variable body motion has been presented and the description of Atwood device given in view of explaining the essence of a real equilibrium of the system of material bodies where their real inertia is of importance. In conclusion the characteristics of real inertia force being the measure of this inertia is presented. The erroneous up-to-date view concerning the measure of body inertia, assuming mass as the measure of this magnitude enabling free manipulation of the acceleration value, has been revealed. At the end it is stressed that acceleration is always positive in its nature and is existent in each condition of the material reality.

16

Novel Modeling of the Phenomenon of Air-Cooled Solid

Pluta Z., Hryniewicz T.

International Letters of Chemistry, Physics and Astronomy

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2013

|

Vol. 1

1-16

EN

The paper turns the attention to the thermal problems of the solid cooling in air. The physical aspect of mathematic approach has been underlined. The analysis and critical evaluation of Newton's Law concerning the solid air-cooling have been performed. The cognitive path leading to the solution is presented with the result being the body temperature dependence on time of cooling down in the air. Then the course of solution concerning the result of the adequate dependence of temperature of the cooled body on time has been presented. In the study, the stress is put on constant magnitudes chich characterize the susceptibility of solid to the cooling in the air. In the end, the synthetic formulation of all functional characteristics of the thermal phenomenon discussed in the paper, have been presented.

17

Mass Moment Determination Using Compound Pendulum

Pluta Z., Hryniewicz T.

International Letters of Chemistry, Physics and Astronomy

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2013

|

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.

18

Kinetics of Flexibly Fixed Operating Element of a Rotating Device

Pluta Z., Hryniewicz T.

International Letters of Chemistry, Physics and Astronomy

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2013

|

Vol. 3

67-84

EN

The work covers the adequate kinetics of the flexibly fixed working element of a rotating device. First the literature background of the problem has been presented, turning the attention on such systems where the phenomenon of centrifugal displacement of a body due to the rotating of the system occurs. Then the general characteristics of the complex motion of working element has been described. The core of the work is the description of the variable component motions, with the starting point of the description being the source differential equation, presenting this type of dependence of the path length on time. The accelerated angular motion and retarded radial motion have been separated, describing these component motions as the function of time. Based on these detailed descriptions, the trajectory equation of working element, the derivatives and further kinetic magnitudes, have been derived. In the conclusion, the cognitive and practical qualities of the presented solutions of the title problem, have been accented.

19

Adequate Theory of Vertical Motion of a Mass-Elastic System

Pluta Z., Hryniewicz T.

International Letters of Chemistry, Physics and Astronomy

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2013

|

Vol. 6

116-136

EN

The paper covers an adequate theory on vertical motion of the mass-elastic system. This system is an oscillator with the motion being a free harmonic motion. The first extended link of the consideration presents a critical analysis of the existent knowledge referred to this subject. Then the energetic states of the oscillator have been determined. Next the force characteristics of the free harmonic motion of the oscillator are presented. A general source equation of the path/way length and the resulting detailed forms, signalizing extensive possibilities to build up the characteristics, have been presented. Finally the connections between the characteristics of real and simulative motions were derived. It should be added that this first mentioned motion is the subject of adequate description presented here. The simulated motion is referred to the existent classical theory which has been subjected under a critical consideration.

20

Wyznaczanie stałej czasowej oraz chwilowej sprawności płaskiego cieczowego kolektora słonecznego w warunkach rzeczywistych

Zima W., Dziewa P.

Ciepłownictwo, Ogrzewnictwo, Wentylacja

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2012

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T. 43, nr 9

369-374

PL

Badania cieplne kolektorów słonecznych są przedmiotem normy PN-EN 12975-2:2007. Zakres normy obejmuje badania wykonywane z wykorzystaniem symulatora natężenia promieniowania słonecznego oraz wykonywane w warunkach rzeczywistych, a więc nieustalonych. W artykule przedstawiono wybrane wyniki badań cieplnych przeprowadzonych wg wyżej wymienionej normy na stanowisku badawczym, znajdującym się w laboratorium Katedry Maszyn i Urządzeń Energetycznych Politechniki Krakowskiej. Płaski, cieczowy kolektor słoneczny umieszczony jest na zewnątrz i pracuje w warunkach rzeczywistych. W ramach badań wyznaczono stałą czasową kolektora oraz jego chwilową sprawność. Stałą czasową wyznaczono także numerycznie za pomocą opracowanego modelu matematycznego kolektora, a uzyskane wyniki porównano z wynikami eksperymentu. Ponadto, obliczono kąt padania promieniowania słonecznego na powierzchnię kolektora w warunkach (dzień, godzina), dla których wyznaczono jego sprawność chwilową.

EN

The article presents selected results of thermal investigations conducted according to the PN-EN 12975-2:2007 standard on the laboratory stand located in the Faculty of Mechanical Engineering in Krakow University of Technology. The flat liquid solar collector working in real conditions has been placed outside. The study determined the time constant and the instantaneous collector efficiency. Time constant was also determined numerically by using the developed mathematical model of the collector. The results were compared with those of the experiment. We also calculated the angle of incidence of solar radiation on the collector surface corresponding to the time conditions (day, hour), for which it`s instantaneous efficiency has been determined.