Wyniki wyszukiwania - BazTech

1

Optimization of start-up conditions to reduce thermal loads in cooled components of a supercritical steam turbine

Kosman W.

Journal of Power Technologies

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2015

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Vol. 95, spec.

47--53

EN

The paper describes the analysis of a start-up process of supercritical steam turbines. The problem under the investigation is the decrease of thermal loads due to the designs that are specific to this type of machines. The analysis focuses on the main components - the rotor and the inner casing that operate under the highest level of the thermal loads. The analysis involves the determination of the temperature and the stress fields and the behavior in the response to transient loading (thermal elongations). The obtained results allow to compare various cases of the transient loading.

2

Matching of a gas turbine and an upgraded supercritical steam turbine in off-design operation

Kosman W.

Journal of Power Technologies

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2015

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Vol. 95, nr 1

90--96

EN

The results of the research presented in this paper refer to an upgrade of a power generating unit with a supercritical steam turbine of a moderate live steam temperature. The upgrade project involves replacing the high pressure part with a turbine driven by a high live steam temperature and adding a gas turbine. The aim of the upgrade is to increase power generation efficiency. The specific problem analyzed in the paper corresponds to the matching between the gas and steam turbine especially in off-design conditions. The analysis is based on the numerical modeling of the thermodynamic cycles. Various conditions of the operation were simulated. The results obtained enable efficiency to be assessed in the analyzed variants.

3

Wpływ zmiany współczynnika rozszerzalności liniowej na stan naprężeń podczas uruchomienia turbiny na parametry nadkrytyczne

Nowak G., Zalewski A.

Energetyka

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2015

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nr 10

671--673

PL

Wzrost parametrów pracy bloku parowego jest silnie ograniczony przez wytrzymałość materiałów stosowanych na wysokotemperaturowe elementy maszyn i urządzeń. Podnoszenie bowiem temperatury pracy istotnie wpływa na obniżenie własności wytrzymałości elementów. Duże obciążenia cieplne, zwłaszcza w stanach nieustalonych, są źródłem niebezpiecznie wysokich naprężeń termicznych. Zwrócono uwagę na zależność naprężeń w stanach rozruchowych od własności materiałów stosowanych na elementy kadłuba części wysokoprężnej turbiny. Zbadano wpływ współczynnika rozszerzalności liniowej materiału kadłuba oraz pierścieni skurczowych na wartości uzyskiwanych naprężeń.

EN

The rise of steam parameters of power units beyond the critical point leads to a significant increase of thermo-mechanical loading of turbine components. The high intensity of heat transfer between the working medium and the solid material during unsteady operation (start-ups) results in dangerous stresses developed in a massive inner casing. In this paper the influence of the thermal expansion coefficient of shrink rings connecting the casing parts on stress within the casing is investigated. It can be seen that rough estimation of material parameters may lead to underestimation of modeled stress.

4

Ocena skuteczności ekranowania głównych elementów turbiny na nadkrytyczne parametry pary

Kosman W.

Instal

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2013

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nr 12

12--16

PL

W artykule opisano wyniki badań rozwiązań konstrukcyjnych turbin parowych ukierunkowanych na zmniejszenie obciążeń cieplnych. Obszarem badań są turbiny na nadkrytyczne parametry pary zasilane parą świeżą o temperaturze powyżej 600oC. Wysoka temperatura pary wymaga zastosowania dodatkowych ekranów chroniących główne elementy maszyny: wirnik i kadłub wewnętrzny. W opisywanej analizie rozpatrzono stan cieplny elementów chronionych ekranami podczas rozruchu turbiny. Badania przeprowadzono na drodze numerycznych symulacji. Określono zakres zmniejszenia obciążeń cieplnych w stosunku do elementów pozbawionych dodatkowej ochrony. Rozpatrzono także możliwość połączenia osłon termicznych z systemem chłodzenia.

EN

The paper describes the results of the investigations on the steam turbine designs aimed to decrease thermal loads. The analysis focuses on supercritical steam turbines fed with a live steam at a temperature above 600oC. The high temperature of the steam requires additional screens that protect main components of a turbine - a rotor and an inner casing. The analysis involves numerical simulations of transient thermal state of the components protected with the screens during a turbine start-up. This allowed to determine the decrease of the thermal load in reference to a turbine without the screens. Additionally the investigations involved the designs that combined the screens and a cooling system.

5

Feasibility study of forced cooling of a supercritical steam turbine after a shut down of a power generating unit

Kosman W.

Archives of Thermodynamics

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2011

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Vol. 32, no. 3

201-214

EN

Temperature related decrease of steam turbine components is one of the main transient processes that occur during a typical long-term operation. With a natural cooling (no user interference) it takes more than 14 days before the temperature of components reaches the level that allows to open and repair a turbine. It is then reasonable to apply a forced cooling in order to decrease the time between a shut-down of a power generating unit and a beginning of a repair. This paper presents the analysis of application of a forced cooling process to supercritical steam turbines. The main problems under the investigation are the safety issues of the process and the optimization of cooling conditions. The paper describes the safety restrictions and the optimization criteria. The process is analyzed in numerical simulations conducted for various cooling conditions.

6

The possibilities to reduce casing thermal loads of the supercritical steam turbines

Kosman W.

Archives of Thermodynamics

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2009

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Vol. 30, no. 4

149-161

EN

This paper discusses problems corresponding to the design and operation of the supercritical steam turbines in the aspect of thermal loads. The analysis presented here focuses on design solutions, which are specific for supercritical steam turbines. The key problem is the assessment of the possibilities to reduce thermal loads during a standard operation. Presented research is conducted on the two main components of a turbine, namely the rotor and the casing. The obtained results create a basis for further evaluation of the possibilities to reduce the thermal loads.