Wyniki wyszukiwania - Biblioteka Nauki

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Wyznaczanie transmitancji z wykorzystaniem odpowiedzi skokowej w obecności zakłóceń

100%

Purczyński J. , Pęksiński J. , Mikołajczak G.

Poznan University of Technology Academic Journals. Electrical Engineering

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2013

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tom No. 73

51--56

PL

W pracy rozpatrzono zagadnienie identyfikacji układu dynamicznego opisanego równaniem różniczkowym zwyczajnym rzędu n bazujące na zmodyfikowanej metodzie momentów. Klasyczna metoda momentów wykorzystuje odpowiedź impulsową układu, natomiast w referacie, proponuje się sposób wykorzystania metody momentów dla odpowiedzi skokowej, bez konieczności różniczkowania numerycznego.

EN

The study examined the issue of identification of a dynamical system described ordinary differential equation of order n based on a modified method of moments. A classic method of moments uses impulse response of the system, and in this paper, it is proposed how to use the method of moments for the step response, without the need for numerical differentiation.

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Modelowanie i symulacja procesów w instalacjach przemysłowych z wykorzystaniem oprogramowania FLOWNEX SE

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Cieślakiewicz W.

Journal of Polish Safety and Reliability Association

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2011

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tom Vol. 2, No. 3

97--106

EN

The recent focus on reliability and safety of industrial systems has raised the need for system simulations and analysis. The intrinsic capabilities of modern computational software development have made it possible to predict trends in various system operations more exactly. The present simulation methodology also allows for the analysis of non-measurable numbers, like the Reynolds Number (Re), which hasn’t been taken so often into consideration during past analyses. The main purpose of this article is to overview the system simulation methodology, focusing primarily on System Computer Fluid Dynamic (SCFD) method as the most effective approach to simulate the flow-thermal networks. This article makes use of system simulation models, which depict real industry problems.

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Use of NaNiCl battery for mitigation of SOFC stack cycling in base-load telecommunication power system - a preliminary evaluation

75%

Kupecki J. , Motylinski K. , Ferraro M. , Sergi F. , Zanon N.

Journal of Power Technologies

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2016

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tom Vol. 96, nr 1

63–-71

EN

Fuel cells are among the most promising technologies for clean power generation. Solid oxide fuel cells (SOFC) are characterized by high efficiency, fuel flexibility and a wide range of operating conditions. SOFC are the preferred fuel cell technology for micro-combined heat and power (micro-CHP) units, but they are prone to rapid performance degradation when exposed to thermal and electrical cycling. To overcome this issue, alternative methods are sought to assure high durability and long-lasting operation by mitigating the cycling. This can be achieved by limiting the number of cycles and maintaining stable operating conditions. One of the proposed solutions is to create a hybrid system combining an SOFC stack with a molten salt (NaNiCl) battery module. The NaNiCl battery is well known for its high energy density, high durability and zero electrochemical self-discharge. This hybrid system is a solution in which the fuel cell stack and the battery module are thermally and electrically integrated and operate as a part of a cogenerator. Since both modules operate at elevated temperature, heat generated in the stack can be partially used to maintain a sufficient operating temperature of the battery pack. The SOFC/battery hybrid enables high operational flexibility which is achieved by proper selection of the power ratios between the two components. In this configuration the battery pack can be used to stabilize operation of the fuel cell stack and to allow for load-following operation of the hybrid. To evaluate the operation of a SOFC/battery, the dynamic models of the battery and fuel cell stack were developed in Aspen Hysys 8.5. The simulator enables predictive modeling of various operating conditions corresponding to the different power demand profiles. In the transitional states of the telecommunication system, the hybrid unit can either charge or discharge the battery without cycling the fuel cell stack. Simulations are needed to evaluate the performance of the SOFC/battery hybrid system, in particular to analyze the capability to follow the load profile during operation in island mode.

4

Identification of the ship's hull impact load on the base on the power transmission system's vibrations measurements

75%

Dąbrowski Z. , Grządziela A.

Journal of KONES

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2007

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tom Vol. 14, No. 4

67-74

EN

The following paper presents the results of an experiment in which an influence of underwater explosions on the ship's power transmission system dynamics was measured. The results, obtained for two different configurations of the object's position and the explosion's place, were compared. The experiment was conducted while the power transmission system was working, so that it was possible to define the relation between a hull's impact load and the vibrations ofpropeller shaft's bearings. As a result of this research, the methodology of measurements and signal analysis has been elaborated and, in consequence, the obtained data can be used to improve an vibroacoustic diagnostic system working on-line. Localisation of the explosives, the configuration of measurements points, measuring time before and after explosion, the comparing of the signal analysis using RMS and Peak value of the acceleration, the comparing of the signal analysis results in two frequency bands, the comparing of the signal analysis results, the comparing of the two explosion effects, the comparing of the two explosion effects are presented in the papers.

PL

W artykule przedstawiono wyniki eksperymentu w którym badano wpływ wybuchów podwodnych na dynamikę układu napędowego okrętu. Porównano wyniki dla dwóch różnych usytuowań obiektu w stosunku do miejsca eksplozji. Eksperyment wykonano podczas pracy układu napędowego, co pozwoliło określić wpływ impulsowego obciążenia kadłuba na drgania łożysk wału śrubowego. Efektem badań jest opracowanie metodyki pomiaru i analizy sygnału wibroakustycznego pozwalającej na wykorzystanie uzyskanych danych do doskonalenia drganiowego systemu diagnostycznego pracującego w systemie (trybie) on-line. Schemat rozmieszczenia ładunków w trakcie badań, rozmieszczenie punktów pomiarowych, zakres czasu pomiaru przyspieszeń przed i po detonacji, porównanie wyników analiz pulsacji pęcherzy przy wykorzystaniu wartości szczytowej i wartości skutecznej przyspieszeń porównanie analiz przy różnych zakresach częstotliwości, porównanie analiz porównanie oddziaływań dla detonacji, porównanie oddziaływań dla detonacji, są przedstawione w artykule.