Wyniki wyszukiwania - Biblioteka Nauki

1

Determination of transient fluid temperature using the inverse method

100%

Jaremkiewicz M.

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tom Vol. 35, no. 1

61--76

EN

This paper proposes an inverse method to obtain accurate measurements of the transient temperature of fluid. A method for unit step and linear rise of temperature is presented. For this purpose, the thermometer housing is modelled as a full cylindrical element (with no inner hole), divided into four control volumes. Using the control volume method, the heat balance equations can be written for each of the nodes for each of the control volumes. Thus, for a known temperature in the middle of the cylindrical element, the distribution of temperature in three nodes and heat flux at the outer surface were obtained. For a known value of the heat transfer coefficient the temperature of the fluid can be calculated using the boundary condition. Additionally, results of experimental research are presented. The research was carried out during the start-up of an experimental installation, which comprises: a steam generator unit, an installation for boiler feed water treatment, a tray-type deaerator, a blow down flashvessel for heat recovery, a steam pressure reduction station, a boiler control system and a steam header made of martensitic high alloy P91 steel. Based on temperature measurements made in the steam header using the inverse method, accurate measurements of the transient temperature of the steam were obtained. The results of the calculations are compared with the real temperature of the steam, which can be determined for a known pressure and enthalpy.

2

Intelligent velocity picking and uncertainty analysis based on the Gaussian mixture model

84%

Wang X. , Gao Y. , Chen C. , Yuan H. , Yuan S.

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2022

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tom Vol. 70, no 6

2659--2673

EN

The stacking velocity is often obtained manually. However, manually picking is inefficient and is easily affected by subjective factors such as the priori information and the experience of different processors. To enhance its objectivity, efficiency and consistency, we investigated an unsupervised clustering intelligent velocity picking method based on the Gaussian mixture model (GMM). This method can automatically pick the stacking velocity fast, and provide uncertainty analysis as a quality control. Combined with the geometry feature of energy clusters in velocity spectra, taking advantages of the geometric diversity of energy clusters, GMM can ft the energy clusters with different distributions more appropriately. Then, mean values of the final several submodels are located as the optimal velocity, and the multiples are avoided under the expert knowledge and geological rules. In addition, according to the covariance of submodels, we can derive the uncertainty analysis of the final time-velocity pairs, so as to indicate the reliability of picking velocity at different depths. Moreover, the automated interpreted velocity field is used for both normal moveout (NMO) correction and stacking. The comparison with the manual references is adopted to evaluate the quality of the unsupervised clustering intelligent velocity picking method. Both synthetic data and 3D field data have shown that the proposed unsupervised intelligent velocity picking method can not only achieve similar accuracy with manual results, but also get rid of multiples. Furthermore, compared with manual picking, it can significantly improve the efficiency and accuracy in identifying pore and cave structures, as well as indicating the uncertainty of time-velocity pairs by variance.

3

Uncertainty analysis of the kinetic model of natural gas combustion in IC Engine

84%

Mansha M. , Naqvi J. H.

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tom Vol. 14, nr 1

1-4

EN

The purpose of this analysis is to determine the uncertainties originating due to the kinetic parameters of the rate of a reaction proposed kinetic model. A kinetic model consisting of 208 reaction steps and 73 species was adopted for analysis. In the required uncertainty analysis, the accuracy of approximate models, generated by the Chemkin 4.1.1 for pollutant species, is determined. The reactions which contribute the uncertainty in the output concentrations of the pollutnats species formed in the combustion chamber were identifi ed. The percentage contribution to the uncertainty in the output concentrations of pollutants were also determined.

4

Niepewność pomiaru impedancji metodą dopasowania do elipsy

84%

Augustyn J.

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tom R. 57, nr 2

180-183

PL

W artykule przedstawiono porównawczą ocenę niepewności pomiaru impedancji, wyznaczonej za pomocą algorytmu dopasowania do elipsy oraz algorytmu DFT z oknem Hanninga. Wykorzystując metodę Monte Carlo, przeanalizowano wpływ niekoherentnego próbkowania na rozkład prawdopodobieństwa błędu składowych impedancji w układzie współrzędnych biegunowych.

EN

In this paper there is presented comparative evaluation of the result uncertainty of impedance component measurement with use of the ellipse-fitting algorithm and DFT algorithm with Hanning's window under the non-coherent sampling conditions. Impedance compo-nents in both cases are determined on the grounds of pairs of signal samples collected simultaneously, in accordance with the model described by equation (1). After elimination of time, it can be presented as conic curve equation (2). Under asynchronous sampling conditions, the dependence between sampling period Ts and unknown signal period T can be described as (5), in which is a window desinchronisation factor. Then, in order to decrease the influence of the spectral leakage effect, time window w(n) should be used and the values of complex spectrum components should be determined from equation (7), while the unknown impedance components from equation (4). The ellipse-fitting algorithm determines the values of ellipse equation coefficients (8) with use of the least squares method, calculating the eigenvector a corresponding to the least positive eigenvalue . On the basis of the known values of vector a elements, the impedance component values are calculated from equation (12). Characteristics of the compared algorithms have been examined with use of the Monte Carlo method, analysing the influence of non-coherent sampling on the probability distribution of the impedance component error, for two impedances Z1 and Z2 with different values of phase angle. The results of this experiment in the form of bivariate histograms of the resultant relative measurement error of impedance components ?|Z| and ? are presented in Figs. 2-4. The influence of the desinchronisation factor value on random characteristics of the impedance relative measurement error in the form of empirical distribution curves are shown in Figs. 5 and 6.

5

Modelowanie niepewności w opisie matematycznym układu dynamicznego

84%

Orłowski P.

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tom R. 53, nr 2

12-15

PL

W artykule przedstawiono źródła i typy zaburzeń oraz niepewności występujących w układach dynamicznych, oraz szczegółowo opisano sposoby wprowadzania jej do modelu matematycznego układu. W ramach niniejszej pracy przeanalizowano sześć struktur niepewności: addytywną, w sprzężeniu zwrotnym wokół obiektu oraz multiplikatywną i w sprzężeniu zwrotnym zarówno na wejściu jak i wyjściu układu.

EN

Mathematical modelling of uncertainty in dynamical systems is presented in the paper. Sources of uncertainties and perturbations are analysed. Perturbations are classified in four different classes. Uncertainty can be modelled using six different perturbation structures in the model: additive, subtractive, pre-, post- multiplicative, pre- and post- divisional. Properties of all analyzed structures are derived as well as upper bounds for analyzed perturbations.

6

Ocena niepewności rozwiązania w modelowaniu zmienności przestrzennej parametrów ośrodka za pomocą metody kosymulacji

84%

Pirowska K.

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tom R. 68, nr 12

1050--1054

PL

W publikacji poruszono problem analizy niepewności w przypadku stosowania metod symulacji czy kosymulacji. Posiadając zbiór alternatywnych realizacji otrzymanych w wyniku działania tych metod, nie jest możliwe wskazanie najlepszej realizacji, na której można by oprzeć dalsze interpretacje, obliczenia, a finalnie – wydać odpowiednie, strategiczne dla przemysłu nafty i gazu decyzje. Zachodzi potrzeba zastosowania narzędzi, które – uwzględniając wszystkie realizacje – są pomocne w ocenie wyników. Niezbędne jest obliczenie wartości średniej, wariancji warunkowej, przydatne może być też obliczenie rozkładów prawdopodobieństwa czy rozkładów kwantyli. Przy użyciu wymienionych rozkładów, na przykładzie modelowania porowatości metodą kosymulacji sekwencyjnej Gaussa, przedstawiono ocenę niepewności rozwiązania.

EN

In this paper the problem of uncertainty assessment was brought up. In the case of the application of simulation or co-simulation a set of realizations were received as the result. It is not possible to choose the best realization on which to base further interpertations, calculations and, what is most important, make strategic decisions for the oil and gas industry. It is necessary to use tools, which take into account all realizations and are helpful in results assessment. It is essential to calculate the mean values and conditional variance. It can be useful to calculate probability distribution or quantile distribution. In this paper application of these distributions was presented as the example of the uncertainty assessment in porosity modeling using Gaussian sequential co-simulation.

7

Badanie emisji ciepła i dymu z materiałów budowlanych metodą kalorymetru stożkowego według ISO 5660

51%

Kolbrecki A. , Konecki M. , Papis B.

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tom R. 38, nr 3

27-46

PL

W artykule podano podstawy metodyki badań z zastosowaniem kalorymetru stożkowego według ISO 5660. Wykonano analizę niepewności pomiarowych szybkości wydzielania ciepła. Przedstawiono i przedyskutowano wyniki badań otrzymane przy spalaniu wybranych materiałów budowlanych.

EN

The paper includes the test methodology for cone calorimeter using according to ISO 5660. The uncertainty analysis of obtained results was presented. The test results for selected buliding materials has been shown and discussed.

8

Badania parametrów emisji ciepła i dymu wybranych materiałów wykończeniowych metodą SBI

51%

Konecki M. , Kolbrecki A. , Papis B.

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tom R. 38, nr 3

47-59

PL

Przedstawiono wyniki badań emisji ciepła i dymu z wybranych materiałów budowlanych przy zastosowaniu metody SBI. Wykonano analizę niepewności pomiarowych mierzonych wielkości oraz przedyskutowano różnice w wartościach parametrów emisji ciepła i dymu materiałów lignocelulozowych.

EN

The paper presents the heat and smoke results obtained in tests of selected building materials using SBI method. The uncertainty analysis of obtained results was presented. The test results of heat and smoke emission for cellulosic based materials has been shown and discussed.