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Experimental research and CFD analysis of flow parameters in a SCR system for the original part and WALKER’s replacement

Kurzydym Damian, Klimanek Adam, Żmudka Zbigniew

Combustion Engines

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2019

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R. 58, nr 4

13--20

EN

The article presents the results of experimental research and their comparison with CFD simulations for the original selective catalytic reduction system and WALKER replacement. The research was performed to develop the WALKER universal mixer. The SCR prototype without mixer and with the proposed mixer were tested and compared with the original VW part. The next step was reverse engineering, which consisted in scanning the tested parts with a laser and processing their point cloud in Leios2 program. Reverse engineering has allowed the reconstruction of 3D geometry of the tested parts in the Catia v5 program and then preparation their models for computational fluid dynamics. Numerical simulations were carried out in the Ansys Fluent program, thanks to which several quantities were determined e.g. uniformity index of gas flow through the monolith and coefficient of variation as a measure of mixing degree, which have a significant impact on the design of the mixer and the SCR system.

2

Random strength parameters of steel corrugated webs and their influence on the resistance of SIN plate girders

Basiński W., Kowal Z.

Architecture Civil Engineering Environment

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2018

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Vol. 11, no. 3

65--77

EN

In the study, the results of statistical investigations into random strength parameters of steel used to manufacture corrugated webs of SIN plate girders were discussed. The investigations were conducted on samples randomly collected from twenty SIN girders. The corrugated web of the girders was 2, 2.5 and 3 mm in thickness. The girders had been examined before statistical investigations were conducted. Based on the analysis, coefficients of variation of yield strength VRe=D(Re)/E(Re) and partial factors of yield strength γm were identified. The results were compared with factors γm obtained from investigations into thin flat sheets [10]. The impact of yield strength and random cross-sectional area of folded web on the quantile of girder web resistance was shown. Taking into account random character of yield strength and web thickness offers a sensible approach to SIN girder design and computations.

3

Robust estimation of variance coefficient with excess of observation errors distribution (VRy-estimation). Part 1. Theory

Wiśniewski Z.

Technical Sciences / University of Warmia and Mazury in Olsztyn

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2002

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nr 5

73-92

EN

A method of estimation which allows to obtain robust, efficient, invariant and unbiased estimator of the variance coefficient [formula] is derived in the work. The coefficient [formula] occurs in the model of covariance matrix of observation results [formula]. It is assumed that the class of square estimators of the following general form [formula]. The method presended in the paper is the development of proposal described by the author in another paper (Wiśniewski 1999). It consists in searching for such a matrix [formula]. The estimator obtained in such a way, is the most effective for given matrices [formula]. The first part of the paper presents the theory of the proposed method of estimation (called VRy-estimation), where as the, fundamental content of the second part of the paper are empirical analyses of the method, including proposals concerning the creation of the functions [formula].

PL

W pracy wyprowadzono metodę estymacji pozwalającą na uzyskanie odpornego na błędy grube, najefektywniejszego, niezmienniczego i nieobciążonego estymatora współczynnika wariancji [wzór], występującego w modelu macierzy kowariancji wyników pomiaru [wzór]. Zakłada się, że estymator ten należy do klasy estymatorów kwadratowych o ogólnej postaci [wzór]. Wyprowadzona w pracy metoda jest rozwinięciem propozycji przedstawionej przez autora w innej pracy (Wiśniewski 1999). Rozwinięcie to polega na poszukiwaniu takiej macierzy [wzór], która zabezpiecza niezmienniczość i nieobciążoność estymatora, ale minimalizuje wariancję formy kwadratowej [wzór]. Uzyskany w ten sposób estymator jest najefektywniejszy dla ustalonych [wzór] macierzy.. W I części pracy wyprowadzono teorię estymacji (nazwanej VRy-estymacją). Główną treścią II części są przedstawione analizy empiryczne, w tym także propozycje dotyczące tworzenia funkcji [wzór].

4

Robust estimation of variance coefficient with excess of observation errors distribution (VRy-estimation). Part 2. Analysis

Wiśniewski Z.

Technical Sciences / University of Warmia and Mazury in Olsztyn

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2002

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nr 5

93-119

EN

The paper presents basic properties of the VRy-estimation. Some forms of the correcting function and gain functions were proposed. These functions influence substantially the course and properties of the proposed estimation method.

PL

W pracy przedstawiono analizę podstawowych właściwości VRy-estymacji. Zaproponowano także pewne postaci funkcji korygującej i funkcji wzmocnienia. Funkcje te mają istotny wpływ na przebieg i właściwości proponowanej metody estymacji.