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Wyszukujesz frazę "-determination" wg kryterium: Temat


Wyświetlanie 1-8 z 8
Tytuł:
Determination of pseudo-viscosity coefficients for visco-elastic lubricants
Autorzy:
Wierzcholski, K.
Powiązania:
https://bibliotekanauki.pl/articles/247504.pdf
Data publikacji:
2010
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
pseudo elastic coefficients
method of determination
Opis:
In this paper we assume determination of pseudo-viscosity coefficients of visco-elastic non-Newtonian fluid flow directly near the cooperating micro-bearing surface. We show the constitutive stress-strain dependencies of non-Newtonian visco-elastic media with regard to the content of addition of nano-particles. The greater content of nano-particles and influences of superficial layer of cooperating surfaces on the dynamic oil viscosity, the more distinct non-Newtonian properties. The non-Newtonian properties create non-linear dependencies between strain and stress. Moreover the dynamic viscosity or apparent dynamic viscosity of oil often decreases along with shear rate increasing during motion. dynamic viscosity of oil inside very thin boundary layers depends on Young's modulus of the cell body being in contact with the oil. Considered visco-elastic oils with nano-particles have non-Newtonian pseudo-plastic properties, described in the beginning by means of Rivlin-Ericksen constitutive relations. Hence their stress-strain dependencies presented in this paper have the modified Rivlin-Ericksen form. Scientific efforts brought into this elaboration represent an impact to the considered domain by providing for some data on comparisons between boundary conditions for lubrication flow in super thin boundary layer lying on the external surface of biological cells of joint cartilage and boundary conditions for lubrication of micro-bearing of shaft diameter smaller than 2 mm.
Źródło:
Journal of KONES; 2010, 17, 2; 491-496
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research of the influence of marine diesel engine Sulzer AL 25/30 load on theTDC position on the indication graph
Autorzy:
Pawletko, R.
Polanowski, S.
Powiązania:
https://bibliotekanauki.pl/articles/247411.pdf
Data publikacji:
2010
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
kinematic TDC determination
load influence on TDC position
Opis:
The article presents the research results of load influence on errors of the piston Top Dead Centre (TDC) position determined on indication graph with combustion. For TDC determination the method proposed by Polanowski is applied. This method is based on least-squares approximation with model of thermodynamic compression using apolynomial exponent. So, designated TDC are kinematics. This method make possible determination the TDC on the indicator diagram with combustion, as well as the total compression ratio and the dynamic error of pressure (offset). Research were done on the laboratory engine Sulzer 3AL25/30 for load range of 50-250 kW and rotational speed 750 rpm, which corresponds to 15-90% nominal load. Cylinder pressures were recorded with a resolution ofn O.5 OWK by means of multichannel recorder UNITEST 205. For pressure measurements were applied strain gauge pressure sensors Spais Company. For the analysis of indicator diagrams used its own specially developed algorithm and program for the automatic determination of TDC, based on the model of the compression process with the exponent of the polynomial. Simultaneously three parameters were determined: the position of TDC, the total compression ratio and offset the pressure. Additionally set the position of the zeros of the second order derivatives, which are sometimes considered as reference points to TDC of pistons. For smoothing of indicator diagrams their own algorithms and programs of moving approximation by polynomials of 3rd degree was used. The results of research have shown the essential load influence on the errors of TDC positions on indicator diagrams.
Źródło:
Journal of KONES; 2010, 17, 3; 361-368
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Increasing the accuracy of the mean indicated pressure determination by appointment of the TDC cylinder position
Autorzy:
Pawletko, R.
Powiązania:
https://bibliotekanauki.pl/articles/243489.pdf
Data publikacji:
2014
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
Top Dead Centre determination
Mean Indicated Pressure accuracy
indicator diagram analysis
Opis:
The paper describes the problems of mean indicated pressure determination and the piston TDC (Top Dead Centre) position impact on this parameter in marine diesel engines. Mean indicated pressure Pi is one of the most important diagnostic parameters of marine engines. On the basis of its parameter, the assessment of the technical condition of each cylinder as well as the regulation of injection equipment can be made. Most of the available electronic indicators enable automatic calculation of mean indicated pressure on the basis of progress indicator diagram. As the research shows the greatest impact on the accuracy of the designation mean indicated pressure has errors of piston TDC position. These errors can be significant and therefore this may lead to engine misdiagnosis. The actual piston TDC correction methods were discussed, and they justified the need of their use in marine engines, despite the wide use of methods of determining the angular position of the crankshaft. The original method of TDC correction based on the model of curve of the compression with the exponent of a polynomial was introduced. The proposed method of TDC correction has been verified for a different types of marine engines.
Źródło:
Journal of KONES; 2014, 21, 2; 251-258
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Increasing the accuracy of the mean indicated pressure determination by appointment of the TDC cylinder position
Autorzy:
Pawletko, R.
Powiązania:
https://bibliotekanauki.pl/articles/245110.pdf
Data publikacji:
2014
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
Top Dead Centre determination
Mean Indicated Pressure accuracy
indicator diagram analysis
Opis:
The paper describes the problems of mean indicated pressure determination and the piston TDC (Top Dead Centre) position impact on this parameter in marine diesel engines. Mean indicated pressure Pi is one of the most important diagnostic parameters of marine engines. On the basis of his parameter, the assessment of the technical condition of each cylinder as well as the regulation of injection equipment can be made. Most of the available electronic indicators enable automatic calculation of mean indicated pressure on the basis of progress indicator diagram. As the research shows the greatest impact on the accuracy of the designation mean indicated pressure has errors of piston TDC position. These errors can be significant and therefore this may lead to engine misdiagnosis. The actual TDC piston correction methods were discussed, and were justified the need of their use in marine engines, despite the wide use of methods of determining the angular position of the crankshaft. The original method of TDC correction based on the model of curve of the compression with the exponent of a polynomial was introduced. The proposed method of TDC correction has been verified for different types of marine engines.
Źródło:
Journal of KONES; 2014, 21, 4; 397-404
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The dynamic TDC assigning on the marine four stroke engines indication diagram
Autorzy:
Kowalak, P.
Powiązania:
https://bibliotekanauki.pl/articles/243233.pdf
Data publikacji:
2007
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
transport
marine diesel engines
combustion processes
power estimation
determination of piston's TDC
Opis:
Determination of the internal combustion piston engine 's indicated power is a complex task. A number of difficulties lead to lots of solutions utilized to increase the accuracy of the result. This paper reports on the experiments concerned with a four stroke engine's piston dynamic position determination. Although the paper is mostly concerned with the piston's TDC definition, the experimental methodology can be utilized in the entire piston movement determination. A specially developed measuring assembly and its working principle utilized in the experiment have been presented too. It allows the acquiring of a set of time-position coordinates. Based on the coordinates, the mathematical algorithm for dynamic piston positioning can be developed. As the piston movement was being observed from the crankcase side, the methodology proved to be relatively cheap and easier for installation, compared to proximity sensors installed in the cylinder head. The advantage of optical sensors and light pipes being used was reduction of the explosion risk in oil mist environment inside the crank case.
Źródło:
Journal of KONES; 2007, 14, 2; 259-266
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of TDC determination methods on mean indicated pressure errors in marine diesel engines
Autorzy:
Pawletko, R.
Polanowski, S.
Powiązania:
https://bibliotekanauki.pl/articles/242218.pdf
Data publikacji:
2011
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
TDC determination
coordinate of zero value of second derivative
TDC position influence on MIP errors
Opis:
The paper presents the results of comparative analysis of influence of different methods of TDC determination for the calculation errors of mean indicated pressure (MP). Lemag method based on zero point of first order derivative, used in PREMET pressure analyzers, was compared to the method based on a polynomial model of the compression process. Comparisons were made on the operating measurement data obtained on the low speed marine engine RTA96C which forms the main propulsion of the vessel and the medium speed engine MAN L28/32A. Measurements were made with onboard combustion PREMET analyzer. It was found that the method based on zero point of first order derivative can give the deviations of position of TDC in excess of 2°CA which is caused by disturbances associated with the measurement of pressure and interference associated with the generation of the angular axis. These errors are related to the accuracy of the methods of determining of the first derivative and the availability of a sufficient range of pure compression after TDC. The best results of determining the TDC position was obtained from the original method based on a polynomial model of the compression process. It should be emphasized that the proposed method enables individual adjustment of TDC for each cylinder and can be used even when the combustion begins before TDC. The conducted research proved the existence of significant influence of indicator graph TDC location on the mean indicated pressure calculation errors.
Źródło:
Journal of KONES; 2011, 18, 2; 355-363
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wear process in successive time units described by first order recurrences
Autorzy:
Wierzcholski, K.
Powiązania:
https://bibliotekanauki.pl/articles/244485.pdf
Data publikacji:
2014
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
wear determination during slide bearings operating process
first order recurrence equation
class of variable coefficients
Opis:
The numerous tribology problems occurring in power-train and transport industry lead to wear bearing determination solutions. Especially the project designer demand the more and more information referring the slide bearing wear anticipation in succeeding years of machine operations. In this paper a perspective will be provided on what is known about various types of influences which are caused wear effects. Some machinery eventually fails or becomes uneconomical to operate because of single causes for example types of wear, but most mechanical devices succumb to combinations of causes. A direct parallel is seems in the human machine. Therefore this paper presents the methods of solutions of some specific class of ordinary non-homogeneous recurrence equations of first order with variable coefficients occurring in hydrodynamic theory of bearing wear problems. The various coefficients occurring in considered recurrent equations are determined from experimental measurements where the influence of various operating parameters on the wear effects is taking into account. The influence of numerous operating parameters on the wear effects is experimentally determined in the case if mentioned parameters are independent as well if are mutually connected. Moreover in this paper the theorems will be presented of the existence, determination and an algorithm construction of discrete solutions of non-homogeneous, linear, first order recurrent equations with variable coefficients. The Lemmas and Theorem are formulated and proved by means of the Unified Operator of Summation (UOS operator) with a unitary translation operator, where the operator properties and features are taking into account. In the case of the space of solution functions, the above mentioned wear problems determination are attributed to practical applications related to the non-homogeneous, linear, first order differential equations. The examples presented in this paper for various variable coefficients i.e. for various operating conditions determine the wear values of micro- bearing system during the indicated time units of operating time.
Źródło:
Journal of KONES; 2014, 21, 3; 285-292
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Statistical evaluation of propriety of measurements of ship’s movement parameters
Autorzy:
Charchalis, A.
Polanowski, S.
Powiązania:
https://bibliotekanauki.pl/articles/244984.pdf
Data publikacji:
2016
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
diagnostics
vessel’s propulsion systems
ship propulsion characteristics for ships with fixed propeller modelling
determination of power characteristics
Opis:
The paper presents some problems of carrying out measurements of energetic characteristics and vessel’s performance in the conditions of sea examinations. As the object of propulsion characteristic determination was selected the ship with fixed pitch propeller. In order to formulate models of power characteristics, in first, known physical aspect were taken and subsequently statistic theory was implemented. Models of propulsion performance were built basing on two theoretical methods of determination of required shaft power and torque at a hub, as the function of propeller’s revolutionary speed and sailing condition represented by dimensionless coefficients. Model number one, based on Silukov method presents function with variable power index, of shaft power in domain of revolutionary speed. The second one presents model of torque variations, based on Silovic – Fancev method. For verification of models were taken presented in available bibliography, results of researches of ship’s propulsion systems [6]. We also discuss the manner of reducing the results of measurements to the standard conditions. We present the way of preparing propulsion characteristics and the analysis of examination uncertainty for the measurement of torque. Statistical analysis of deviation of results, using three models, proposed in the paper. As a result of analysis, one point from primary data set was rejected due to its unreliability, what was resulting with higher adequacy of characteristics.
Źródło:
Journal of KONES; 2016, 23, 1; 83-89
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-8 z 8

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