Wyniki wyszukiwania - BazTech

1

A study of noise emission from a gas turbine

Hočevar M, Širok B, Donevski B, Dvoršek M

Zeszyty Naukowe. Cieplne Maszyny Przepływowe - Turbomachinery / Politechnika Łódzka

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2008

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nr 133

149--156

EN

An analysis of low frequency noise emissions from a gas turbine was performed. Vibrations from the stack elbow, noise in the near field of the elbow, and fluctuations of light intensity in the combustion chamber were measured simultaneously. The presented results point out the origin of the low-frequency noise in the combustion chamber. By applying cross-correlation analysis, the quasi-periodic, non-linear nature of the relationship between optical pulsations in the turbine's combustion chamber and the signal of noise outside the flow tract is shown.

2

Numerical Simulation of the Fluid Flow between Blades and around the Turbine Blade

Chodkiewicz R., Donevski B.

Zeszyty Naukowe. Cieplne Maszyny Przepływowe - Turbomachinery / Politechnika Łódzka

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2005

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nr 128, vol. 1

115-121

EN

This paper presents the results of the investigations of a flow in the turbine cascade and is a contribution to development of both the numerical method and modification of upgrading of the mathematical models describing the flow physics in the turbine cascade. The objective is to classify the factors which affect the efficiency of the turbine stage operation at defined thermodynamics properties of steam. The numerical computation is conducted for the two stage turbine model at the Institute of Turbomachinery, Technical University of Lodz. In the computations, a CFD computer code CFX-TascFlow was used, based on solving Navier-Stokes equations with the standard κ-ω SST (Short-Stress Transport) model. The results of the numerical computation are discussed in the paper as well.

3

Numerical computation of steam flow in power plant condensers utilizing the three-dimensional procedure

Ostrowski K., Brodowicz K., Donevski B., Nedelkovski I., Stefanovska C., Nikolovski G.

Transactions of the Institute of Fluid-Flow Machinery

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1998

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nr 104

31-44

EN

One of the salient shortcomings of the most present computational methods for predicting the steam flow in the power plant condensers is the limitation of two-dimensional or quasi three-dimensional flows. However, the flow in the untubed region of condensers (from turbine exhaust to the outer circumference of the tube bundle) is markedly three-dimensional, and the distribution of steam around the tube bundle is made even more three-dimensional because of the temperature difference caused by the cooling water. The steam flow in the axial direction in the tube bundle region, is constrained by supporting plates. However, the three-dimensional modeling is necessary and important in providing an accurate prediction of the flow, especially in the regions of air suction. A practical approach is thus needed to establish an algorithm, in which included are the three-dimensional effects in a real and practical manner, in both the untubed and tubular regions in the condensers of the power plant. A full of description of the three-dimensional procedure for a numerical computation of the steam flow in power plant condensers is presented in this paper. The purpose of the present study is to develop an algorithm that can be used to predict the nature of the three-dimensional fluid flow and heat transfer in large condensers of power plants. In order to demonstrate the applicability and predictive capability of the proposed method, both the three-dimensional and two-dimensional procedures are applied to simulate velocity, pressure and fraction of air mass experimental condensers. Numerical results obtained are compared with the experimental results of these condensers, as they appear in the scientific relevant literature on numerical simulation.

PL

Praca ta zawiera wyniki symulacji numerycznej przepływu i kondensacji pary w eksperymentalnym skraplaczu z zastosowaniem dwu- i trójwymiarowego matematycznego modelu obliczeniowego. Dla porównania zaprezentowano wyniki eksperymentalne, jak również, wyniki dwu- i trójwymiarowych obliczeń, opublikowane w wyszczególnionej literaturze. Na bazie przeprowadzonej analizy, można stwierdzić, że wyniki obliczeń z zastosowaniem trójwymiarowej symulacji numerycznej nie zawierają znaczących różnic w stosunku do dwu- i quasi trójwymiarowych obliczeń, dla warunku brzegowego na wlocie do skraplacza w postaci stałego pola prędkości pary. Należy jednak podkreślić, że zalety modelu trójwymiarowego są widoczne dla przypadku obliczeń, w których zastosowano niejednolite pole prędkości jako warunek brzegowy na wlocie do skraplacza. To niejednolite pole prędkości, odpowiada rzeczywistym warunkom panującym w skraplaczu, umiejscowionym na wylocie z turbiny. Otrzymane wyniki potwierdzają konieczność prowadzenia symulacji numerycznych przepływu pary zarówno w turbinie jak i w skraplaczu. Pole prędkości na wylocie z turbiny, otrzymane z symulacji numerycznej turbiny, będzie wykorzystane jako warunek brzegowy na wlocie do skraplacza, do dalszych obliczeń cieplno-przepływowych w przestrzeni skraplacza.