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1

Wet steam flow in 1100 MW turbine

Jun Gukchol, Kolovratník Michal, Hoznedl Michal

Archives of Thermodynamics

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2021

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Vol. 42, no 3

63--85

EN

The paper deals with the wet steam flow in a steam turbine operating in a nuclear power plant. Using a pneumatic and an optical probe, the static pressure, steam velocity, steam wetness and the fine water droplets diameter spectra were measured before and beyond the last turbine low-pressure stage. The results of the experiment serve to understand better the wet steam flow and map its liquid phase in this area. The wet steam data is also used to modify the condensation model used in computational fluid dynamics simulations. The condensation model, i.e. the nucleation rate and the growth rate of the droplets, is adjusted so that results of the numerical simulations are in a good agreement with the experimental results. A 3D computational fluid dynamics simulations was performed for the low-pressure part of the turbine considering non-equilibrium steam condensation. In the post-processing of the of the numerical calculation result, the thermodynamic wetness loss was evaluated and analysed. Loss analysis was performed for the turbine outputs of 600, 800, and 1100 MW, respectively.

2

Light extinction and ultrasound method in the identification of liquid mass fraction content in wet steam

Majkut Mirosław, Dykas Sławomir, Smołka Krystian

Archives of Thermodynamics

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2020

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Vol. 41, no 4

63--92

EN

Recently, significant progress has been made in experimental studies on the flow of wet steam, measuring techniques based on recording the phenomenon of extinction of light and ultrasound have been elaborated or improved. The basic value experimentally determined in the final stage was the content of the liquid phase defined as the wetness fraction. The methodology of tests and experimental investigations was presented, as well as the applied and developed measurement systems. Next, some developed designs of new ultrasonic and light extinction measuring probe and their modifications are described. The article presents also some examples of applications of the developed measurement techniques in application to experimental research conducted on wet steam. Examples of comparison between experimental and numerical tests for the extinction method are also provided.

3

Pary

Litke Benedykt Julian

Problemy Nauk Stosowanych

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2018

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T. 9

43--50

PL

Wstęp i cele: W pracy opisano proces wytwarzania pary, parametry pary mokrej, parę przegrzaną, oraz wykresy graniczne pary. Celem pracy jest opis graficznego przebiegu temperatury substancji przy izobarycznym podgrzewaniu, podanie charakterystyk pary mokrej i pary przegrzanej oraz opis graficzny pary wodnej. Materiał i metody: Materiał stanowią źródła z literatury z zakresu termodynamiki. W pracy zastosowano metodę analizy teoretycznej. Wyniki: Rezultatem analizy jest opracowanie analityczne procesu wytwarzania pary, parametrów pary mokrej (wilgotnej) oraz przedstawienie graficzne wykresów granicznych pary. Wnioski: W czasie podgrzewania cieczy przy wyższym ciśnieniu, temperatura nasycenia jest wyższa. Czas parowania cieczy zmniejsza się ze wzrostem ciśnienia. Przy wyższym ciśnieniu do odparowania cieczy wymagana jest mniejsza ilość ciepła. Proces izobarycznego parowania jest również procesem izotermicznym. Wartości parametrów termodynamicznych pary mokrej zależą więc od stopnia suchości.

EN

Introduction and aim: The work describes the steam generation process, wet steam parameters, superheated steam, and steam limit graphs. The aim of the work is to describe the graphic temperature course of the substance during isobaric heating, to provide the characteristics of wet steam and superheated steam and a graphic description of the water vapor. Material and methods: Material covers some sources based on the literature in the field of thermodynamics. The method of theoretical analysis has been shown in the paper. Results: The result of the analysis is the analytical development of the steam generation process, the parameters of the wet (damp) steam and the graphic representation of the steam boundary graphs. Conclusion: When the fluid is heated at a higher pressure, the saturation temperature is higher. The evaporation time of the fluid decreases with increasing pressure. At higher pressure, less heat is needed to evaporate the fluid. The process of isobaric evaporation is also an isothermal process. The values of thermodynamic parameters of wet steam depend on the degree of dryness.

4

Evaluating the eﬃciency of low pressure part of steam turbines based on probing measurements

Gardzilewicz A.

Transactions of the Institute of Fluid-Flow Machinery

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2017

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nr 135

41--56

EN

A methodology oﬂow pressure part turbine eﬃciency evaluation based on measurements of the steam ﬂow parameters in the interspaces between neighbouring stages is described. Specially manufactured probes have been applied carry out such measurements. The eﬃciencies of the stages operating in the superheated steam zone result directly from experimental values of pressures, temperatures, and ﬂow angles. To complete the eﬃciency evaluation for the stages operating in the wet steam region, a relevant estimation of blading system losses has been proposed and validated. This evaluation of losses is compatible with the measurement results. Adaptation of a comparative error analysis makes it possible to show the advantages of the methodology over the thermal balance applied during performance tests. The low pressure turbine eﬃciency evaluation methodology has been applied to numerous steam turbine power units of 200–500 MW output.

5

Influence of operating parameters on thermodynamic efficiency of experimental turbine with 1000 MW HP part

Hoznedl M., Bednář L., Miczán M., Tajč L.

Zeszyty Naukowe. Cieplne Maszyny Przepływowe - Turbomachinery / Politechnika Łódzka

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2014

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nr 146

79--87

EN

The results of experiments performed on a 5-stage steam turbine are presented. Operating parameters close to the real design parameters are simulated. The modes with the slightly different input temperature and pressure are also considered. Thermodynamic efficiency defined based on the torque moment by measuring on a water brake is compared with efficiency evaluated from the temperatures and pressures. An analysis of velocity ratios and efficiency of individual stages is carried out.

6

Experimental and numerical study on condensation in transonic steam flow

Majkut M., Dykas S., Strozik M., Smołka K.

Zeszyty Naukowe. Cieplne Maszyny Przepływowe - Turbomachinery / Politechnika Łódzka

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2014

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nr 145

89--90

EN

The present paper describes an experimental and numerical study of steam condensing flow in a linear cascade of turbine stator blades. The experimental research was performed on the facility of a small scale steam power plant located at Silesian University of Technology in Gliwice. The test rig of the facility allows us to perform the tests of steam transonic flows for the conditions corresponding to these which prevail in the low-pressure (LP) condensing steam turbine stages. The experimental data of steam condensing flow through the blade-to-blade stator channel were compared with numerical results obtained using the in-house CFD numerical code TraCoFlow. Obtained results confirmed a good quality of the performed experiment and numerical calculations.

7

Research on steam condensing flows in nozzles with shock wave

Dykas S., Majkut M., Smołka K., Strozik M.

Journal of Power Technologies

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2013

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Vol. 93, nr 5

288--294

EN

The paper presents experimental and numerical results of steam transonic flows in Laval nozzles. The geometries of half arc nozzles were used in testing. Subject to investigation was the behavior of shock waves in the wet steam region. Due to high back pressure the shock wave was created in the divergent part of the nozzle, and interaction with the nozzle walls caused instability in the flow. The experimental results were compared with numerical calculations of steam condensing transonic flow.

8

Models for water steam condensing flows

Wróblewski W., Dykas S., Chmielniak T.

Archives of Thermodynamics

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2012

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Vol. 33, no. 1

67-86

EN

Abstract The paper presents a description of selected models dedicated to steam condensing flow modelling. The models are implemented into an in-house computational fluid dynamics code that has been successfully applied to wet steam flow calculation for many years now. All models use the same condensation model that has been validated against the majority of available experimental data. The state equations for vapour and liquid water, the physical model as well as the numerical techniques of solution to flow governing equations have been presented. For the single-fluid model, the Reynolds-averaged Navier-Stokes equations for vapour/liquid mixture are solved, whereas the two-fluid model solves separate flow governing equations for the compressible, viscous and turbulent vapour phase and for the compressible and inviscid liquid phase. All described models have been compared with relation to the flow through the Laval nozzle.

9

Możliwości badań eksperymentalnych przepływu pary mokrej w układzie mini-siłowni kondensacyjnej

Smołka K., Strozik M., Majkut M., Dykas S.

Prace Naukowe Politechniki Warszawskiej. Konferencje

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2011

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z. 27

233--240

PL

W Instytucie Maszyn i Urządzeń Energetycznych Politechniki Śląskiej od bardzo wielu lat prowadzone są badania naukowe z wykorzystaniem parowej mini-siłowni kondensacyjnej znajdującej się w Hali Maszyn Cieplnych. Jest to jedyna znana niekomercyjna instalacja tego typu w Europie składająca się z kotła parowego, turbiny parowej ze skraplaczem, generatora elektrycznego, chłodni kominowe] oraz tunelu do badań przepływu pary mokrej. W artykule przybliżone przeznaczenie i budowę instalacji stanowiska badawczego do przepływów pary mokrej z kondensacją oraz plany jego wykorzystania. W aktualnym stanie tunel ten stanowi interesującą instalację badawczą do analizy wielu zagadnień przepływowych.

EN

In the Institute of Power Engineering and Turbomachinery of The Silesian University of Technology the experimental research have been performed from many years now. To this end a mini steam power station located in Machinery Hall is used. It is unique noncommercial installation of such kind in Europe, consisting of a steam boiler, steam turbine with condenser, electric generator, cooling tower and tunnel to the wet steam flows. In this paper has been presented purpose and construction of wet steam tunnel and plans for its use. In the present state of this tunnel is an interesting research installation for the analysis of many problems of flow.

10

Numerical estimation of losses in steam flow through LP turbine blade rows

Dyskas S., Wróblewski W.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

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2006

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Vol. 10, No 2

177-190

EN

The aim of this work is to estimate the losses in steam flow through an LP steam turbine rotor and the who]e stage. Two types of losses occur in steam flow, aerodynamic (profile, secondary flow, leakage) and thermodynamic (due to addition of heat caused by condensation). The presented numerical results are split into two groups. First, a comparison of three different calculation methods of steam flow is carried out. To this end, the geometry of an LP steam turbine's last rotor is chosen. The first examined method is the Streamline Curvature Method (SCM) used on the meridional plane with loss correlations, the other two being commercial and in-house CFD codes, solving the Reynolds-averaged Navier-Stokes equations for a 3D flow. The first two codes model equilibrium steam properties below the saturation line, while the latter models non-equilibrium steam properties. Finally, a comparison is made of the influence on lass prediction of various condensation models for the geometry of the penultimate stage, with the use of an in-house CFD code.

11

Numerical prediction of losses in the low pressure last stage blade

Chmielniak T., Łukowicz H., Wróblewski W., Dykas S.

Transactions of the Institute of Fluid-Flow Machinery

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2003

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nr 113

119--128

EN

The aim of presented research is to estimate the losses in the flow of steam through the rotor of last stage LP steam turbine. In this case two types of losses may take place, namely aerodynamic (profile, secondary flow, leakage) and thermodynamic (due to the heat addition caused by condensation). In the paper three different calculation models have been compared. The first one is the streamline curvature method (SCM), used on the meridional plane with correlation of losses, and the other are based on the Reynolds averaged Navier-Stokes governing equations. The N-S equations for the 3D steam flow are solved using two models for the liquid phase. The first one is an equilibrium dry/wet steam model and the second one is the nonequillibrium model. In this case, the governing equations are coupled with the system of partial differential equations describing the liquid phase. The real gas local equation of state is used in calculation of the water-steam properties and thermodynamic functions. The homogeneous nucleation processes in the water steam are modeled using the classical nucleation theory. Flow in the considered case has strong 3-D character and real gas effects are significant, which causes significant losses in the last stages. The results of calculations of the wet steam flow are discussed and compared.

12

Numerical simulation of spontaneously condensing flows in a plane turbine cascade

Li L., Li G., Feng Z.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

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2002

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Vol. 6, No 1

209-216

EN

The low efficiency of wet steam turbine is mainly attributed to wetness losses. To investigate the mechanisms which give rise to these losses, a fully Eulerian model has been developed for calculation of the wet steam flows with spontaneous condensation. In this model, the liquid phase is described with two conservation equations in Eulerian form and coupled with a solver of gas dynamics equations. With such a model, the existing code for simulation of single-phase flows can easily be changed to include wet steam two-phase flows in wet steam turbines. A numerical simulation of condensing flow in a plane turbine cascade is performed, and the numerical results are presented and compared with the experimental results.

13

Investigation of wet steam flow in LP steam turbine using a novel integrated probe: experimental results

Wang L., Cai X., Ouyang X.

Archives of Thermodynamics

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2002

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Vol. 23, no 4

49-57

EN

In low-pressure (LP) steam turbine, the wetness fraction of steam causes dangerous erosion of turbine blades and decrease of turbine efficiency. In the study of wet steam flow, wetness, droplet size and velocity are of the main concern. These parameters are closely correlated to the vapour phase of the flow field and have to be measured simultaneously. Following this line, a novel integrated probe system has been successfully developed, based on light scattering technique, correlation theory and common methods for flow field measurement. By using this system, experiment has been performed in a 200 MW and a 350 MW condensing steam turbine. Part of the results are presented and some newly detected phenomena are put forward and discussed.

14

Instalacja do badania przepływu pary przegrzanej i mokrej ze zjawiskami kondensacji

Mańka G., Łukowicz H., Werbowski T., Wróblewski W., Dykas S.

Zeszyty Naukowe Katedry Mechaniki Stosowanej / Politechnika Śląska

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2001

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z. 15

215-220

PL

W artykule przedstawiono koncepcję stanowiska pomiarowego do badania przepływów pary wodnej przez dysze i kanały łopatkowe, metodykę i zakres pomiarów, uzyskane wstępne wyniki badań oraz przykłady otrzymanych wizualizacji zjawiska kondensacji. Przedstawione wyniki badań eksperymentalnych potwierdzają celowość budowy stanowiska. Uzyskana wysoka zgodność rezultatów obserwacji z przyjętym modelem numerycznym pozwala przypuszczać, że w miarę gromadzenia większej ilości wyników doświadczeń możliwa będzie dokładna analiza ich porównania z opracowanym w Instytucie algorytmem obliczeniowym.

EN

The article shows a concept of measuring stand for studies of steam flow through nozzles and blade channels, methods and scope of measurements, obtained initial results and visualization examples of condensation phenomena. The presented experiment results support purposefulness of stand construction. High fidelity of obtained results with assumed numerical model allows to presume that along with a growing amount of data from further experiments, a more detailed analysis of their comparison with our Institute's numerical algorithm should be possible.

15

Numerical calculation of the steam condensing flow

Dykas S.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

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2001

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Vol. 5, No 4

519-535

EN

Considering the flow in the last stages of LP (low pressure) steam turbine the strong non-linearity of the thermal parameters of state and possibility of the two-phase flow have to be taken into account in the numerical calculation of the flow field. In this paper numerical calculations of the steam condensing flow for the turbine geometry are presented. The steam properties are described here on the basis of the IAPWS’97 formulation. The classical nucleation theory of Volmer and Frenkel was adapted for modelling of condensing flow. The droplet growth model of Gyarmathy is implemented. The calculations are based on the time dependent 3D Euler equations, which are coupled to three additional mass conservation equations for the liquid phase and are solved in conservative form.