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1
Content available A role of the heat and work uncompensated transformations in the balance of entropy and the turbomachinery efficienc
Kowalczyk T., Ziółkowski P., Sławiński D., Cisak M., Badur J.
Transactions of the Institute of Fluid-Flow Machinery
|
2017
|
nr 135
11--27
EN
The notion of heat uncompensated transformation has early been introduced by Clausius in 1854 and next, after fifty years of forgetting, in 1904 Duhem has revalorized it and combined it with a new notion of work uncompensated transformation [3]. In this way the so-called ClausiusDuhem inequality has been established. In our paper we wish to present a novelized procedure of estimating the role of the uncompensated transformations of heat and work within the flow of viscous and heat conducting working fluid like water stream. The original procedure was introduced by Puzyrewski and it is essential in expressing of a local, in time and space, balance of entropy. Futhermore, this unique approach leads to redefinition of the efficiency notion, as is usually applied to fluid-flow machineries, to a new one important in computational fluid dynamics (CFD) three-dimensional modeling. As a result, it is shown that usage of the polytropic efficiency, instead of the isentropic efficiency, is more convenient and seems to be natural in CFD approach. Helpfully, we have also found a correlation between those two efficiency definitions with usage of proposed new dimensionless (criterion) number.
2
Content available remote Zastosowanie techniki numerycznej CFD do modernizacji stopni turbin parowych części NP w obrębie upustów regeneracyjnych
Szymaniak M.
Mechanik
|
2016
|
R. 89, nr 7
840--841
PL
W artykule przedstawiono sposób poprawy pracy stopnia turbinowego wraz z wymiennikiem regeneracyjnym poprzez wprowadzenie pierścienia zgarniającego parę z przecieku nad niebandażowaną łopatką wirnikową bezpośrednio do komory upustowej. Przedstawiono porównanie wyników obliczeń numerycznych dotyczących konstrukcji z zamontowanym pierścieniem i oryginalnej. Obliczenia numeryczne niezmodernizowanej konstrukcji zostały wykalibrowane na podstawie pomiarów wykonanych na rzeczywistym obiekcie pracującym w jednej z polskich elektrowni.
EN
The article presents a methodology which has led to the improvement of turbine stage performance in the area of the regenerative steam extraction chamber by introducing a ring which collects the leakage flow from over unshrouded rotor blade tips and directs it to the extraction chamber. Comparison is made between the results obtained for the initial design (without a ring) and that with the mounted ring. The results obtained for the initial construction were calibrated on the data measured on a real turbine in a Polish power plant.
3
Content available On the internal efficienty of a turbine stage: classical and computational fuid dynamics definitions
Nastałek L., Karcz M., Sławiński D., Zakrzewski W., Ziółkowski P., Szyrejko C., Topolski J., Werner B., Badur J.
Transactions of the Institute of Fluid-Flow Machinery
|
2012
|
nr 124
17--39
EN
Almost entire fleet of steam turbines in Poland was designed between 1950_1980 with the use of the so-called zero-dimensional (0D) calculation tools. For several years, design and modernization of the turbines occur in assistance with the state-of-the-art methods that describe working fluid flow field based on three-dimensional (3D) models and computational fluid dynamics (CFD) codes. This cooperation between 0D and 3D codes requires exchange of overall, integral information such as: power, efficiency, heat and mass fluxes. In consequence the question arises regarding the cohesion of definitions, and particularly regarding the correctness of the definition for internal efficiency of the turbine's stage and the turbine as a whole. In the present paper we formulate basic definitions reason of efficiency that are naturally adapted to the numerical 0D and 3D models. We show that the main reason of differences between the definitions in 0D and 3D is the definition of the theoretical work of the stage lt. In the classical 0D models, mostly employed is the isentropic approach, and hence the isentropic efficiency occurs. Meanwhile, in the increasingly common 3D approach (most likely by CFD), we use more physically correct pathway by subtracting energy loss from the available energy, that leads to the polytropic definition of efficiency. We show an example of computing the efficiency and the 3D losses, denoted with additional subscript CFD, we also discuss benefits of this definition in comparison with the isentropic classical definition in 0D.
4
Content available remote The effect of the turbulence model on the turbine stage flow exit angle distribuation
Świrydczuk J.
TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk
|
2012
|
Vol. 16, No 3-4
239--252
EN
The article analyses the effect of the turbulence model on the calculated exit angles of the flow leaving the rotor of a low-pressure turbine stage. Three turbulence models were taken into account: the algebraic Baldwin-Lomax model and two advanced differential models based on the Shear Stress Transport (SST) approach proposed by Menter. The calculated results have revealed that even such extremely different turbulence models impose little difference in the resultant averaged flow exit angle distributions, especially in stages in which a regular flow pattern without flow separation and/or other irregularities is observed. Larger differences can be observed in local distributions of this parameter, especially in the regions of activity of secondary vortex structures.
5
Content available remote Secondary Flow Structures and Resultant Exit Flow Angle Fluctuations in High Pressure Steam Turbine Stage
Świdryczuk J.
TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk
|
2010
|
Vol. 14, No 1-2
15-28
EN
The object of investigation is the stage, the geometry and flow conditions of which are typical for a series of steam turbines in operation in Polish power plants. The flow analysis is based on the CFD calculations performed using FlowER, a specialized URANS code developed for studying unsteady phenomena in turbine stages and sections. The paper presents flow patterns illustrating the interaction between vortices inside and downstream of the rotor passage and the resultant exit flow angle (EFA) fluctuations recorded at the stage exit. An attempt is made to attribute individual EFA fluctuations to particular vortices and their development stages.
6
Content available remote Modernisation of Steam Turbine Construction at Regenerative Steam Extraction Point
Szymaniak M., Gardzilewicz A.
TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk
|
2010
|
Vol. 14, No 4
319-327
EN
The paper presents a methodology which has led to improvement of the turbine stage performance in the regenerative steam extraction chamber area by introducing a ring which collects the leakage flow from the gaps over unshrouded rotor blade tips and directs it to the extraction chamber. A comparison is made between the results obtained for the initial design (without a ring) and the design with the ring mounted. The results obtained for the construction were calibrated using the data measured on a real turbine in a Polish power plant.
7
Content available remote Vortex interactions in an hp turbine rotor and their effect on stage performan
Swirydczuk J
Zeszyty Naukowe. Cieplne Maszyny Przepływowe - Turbomachinery / Politechnika Łódzka
|
2008
|
nr 133
335--342
EN
The paper presents a CFD analysis of the process of development and mutual interactions of vortex structures in an HP turbine rotor and its effect on stage performance. Two stages selected for examination revealed different efficiency levels and loss distribution patterns. In the low-efficiency stage the analysis, performed in a steady-state mode on a fine-resolution grid, made it possible to trace the interaction of a horseshoe vortex with the separation structures forming in the rear part of the rotor passage, and evaluate the resultant fluctuations of stage performance parameters.
8
Content available remote Modernisation of the last stage in the low- pressure cylinder of a steam turbine using CFD and optimisation techniques
Rusanov A. V., Paschenko N. V., Yakovlev V. A., Yershov S. V.
Zeszyty Naukowe. Cieplne Maszyny Przepływowe - Turbomachinery / Politechnika Łódzka
|
2008
|
nr 133
291--298
EN
The results of gas dynamic improvement of the last stage in the low-pressure cylinder of a steam turbine are presented. The turbine stage performance and the 3D flow patterns were obtained with the CFD solver FlowER. Stage modernisation was carried out in two ways. First, stage blade sections were renovated, and then the 3D blade shape was optimised using the CFD and optimisation techniques. The optimised stage has stator blades with a compound lean at the hub and a compound sweep at the tip. The efficiency of the improved stage is higher by roughly 2 percent at nominal flow conditions and is up to 10 percent for low flow rate conditions as compared to that of the original stage.
9
Content available remote Development of Vortex Structures in a Turbine Stage Rotor Passage
Świdryczuk J.
TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk
|
2008
|
Vol. 12, No 3-4
147-158
EN
The article analyses the formation and development of horseshoe vortices in a highpressure turbine stage rotor passage. Two turbine stages are examined: a standard performance stage, revealing regular performance characteristics and distributions of flow parameters, and a lowefficiency stage in which a large separation zone is observed in rotor passages. In the latter stage the interaction of the hub horseshoe vortex with the separation structures has been found to take a highly unsteady and periodic course and be a source of remarkable flow fluctuations.
10
Content available remote Unsteady performance of an HP turbine stage optimised for steady flow conditions
Świrdyczuk J.
TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk
|
2005
|
Vol. 9, No 2
187-198
EN
The article is focused on the examination of the unsteady performance of an HP turbine stage the blades of which were previously optimised for steady flow conditions. For the purpose of this examination, two pairs of initial and optimised stages of comparable output parameters were selected. The results have revealed that the modification of the blade profile in the optimisation process made the rotor blades more vulnerable to unsteady flow fluctuations, which eventually cancelled a considerable part of the stage efficiency gained from the steady flow optimisation.
11
Content available remote One-dimensional numerical simulation of transient flow in a turbine stage.
Uzunow N.
Archive of Mechanical Engineering
|
2005
|
Vol. LII, nr 3
283-298
EN
The investigation presented in this work concerned one-dimensional modelling of transient flow in an axial turbine stage. Because of the compound motion in the rotor-blade channels, the model of this flow path element was considered the most difficult to solve. The basic modelling approaches and the usefulness of the Euler and Lagrange methods for mathematical description are discussed. Relevant applied model based on the Lagrange method is described. Results of a successful numerical simulation of transient flow in a turbine stage are presented. This success opens the opportunity to build and solve one-dimensional models of dynamic flows in turbine cascades and entire flow paths.
PL
Przedstawiono badania nad jednowymiarowym modelowaniem nieustalonych przepływów przez osiowy stopień turbinowy. Z powodu złożonego ruchu w kanałach wirujących, model tego elementu układu przepływowego turbiny uznano za najtrudniejszy do rozwiązania. Omówiono podstawowe podejścia przy modelowaniu oraz przydatność metod opisu matematycznego Eulera i Lagrange'a. Opisano odpowiedni model stosowany, oparty na metodzie Lagrange'a. Przedstawiono wyniki udanej symulacji numerycznej nieustalonego przepływu przez stopień turbinowy. Sukces ten stwarza możliwość budowy i rozwiązania jednowymiarowych modeli kaskad turbinowych i całkowitych układów przepływowych turbin do badania zachodzących w nich procesów nieustalonych.
12
Content available remote Stator blade modification as a method of leakage flow trearment to improve flow efficiency of old-design steam turbine stages
Lampart P., Gardzilewicz A., Szymaniak M., Kurant B., Banaszkiewicz M., Malec A.
Transactions of the Institute of Fluid-Flow Machinery
|
2003
|
nr 114
19-36
EN
The paper discusses the possibilities of decreasing tip leakage losses in old-design turbines. Two methods of modification - stator blade leading edge cut and unceambered stator blade profile, where the blades of the downstream stator are modified near the tip to better fit to tip leakage flow from the preceding rotor - are presented here and investigated with the help of a CFD code. Changes in flow patterns are described. Also, possible efficiency gains from the applied modifications are estimated in the paper.
13
Wpływ odległości wieńców łopatkowych w stopniach turbiny na straty przepływu
Łukowicz H.
Zeszyty Naukowe. Elektryka / Politechnika Opolska
|
2002
|
Vol. 280, z. 51
463-468
PL
W referacie analizowano wpływ osiowej odległości wieńców łopatkowych na straty energii mechanicznej w stopniu. Przedstawiono rezultaty obliczeń dla częścii wysokoprężnej turbiny o mocy 200MW.
EN
The correct axial clearance between rotor and guide ring is important from leakage losses point of view. When the axial packing is abrasive wearing while the operation, it is required to change the distance between guide ring and rotor ring of the turbine stages. It cause change in a internal efficiency of the stage. The calculation of losses inrease in the turbine stage which was causes by a change in a interring distance in a 200MW turbine have been presented.
14
Efekty zmiany ułopatkowania kierownicy akcyjnego stopnia turbinowego
Wiechowski S.
Gospodarka Paliwami i Energią
|
2001
|
nr 2
22-29
PL
W powietrznej turbinie modelowej zbadano i porównano charakterystyki dwóch stopni akcyjnych oraz kierownic, które różniły się profilami łopatek, katem ich ustawienia i podziałką przy zachowaniu podobnej powierzchni wylotowej wieńca A1.
EN
The characteristics of two impulse stage and their guide vanes are tested in cold air turbine and compared. The both guide wheels have different blade profiles, position angles and pitches and simular autlat stator plane A1.
15
Content available remote Generalized performance characteristics of turbine stage groups. An attempt to supplement the Flugel's-Stodola's law.
Miller Andrzej, Lewandowski Janusz, Trzcińska Zofia, Abed Kamal Ahmed
Archive of Mechanical Engineering
|
2000
|
Vol. XLVII, nr 1
33-52
EN
The knowledge of performance characteristics of tubine stage groups is still insufficient, particularly in the general case of changes of operating conditions. This situation is caused mainly by the scarcity of experimental data available. In such case, the opportunity to obtain the required data, using mathematical modelling and numerical simulation of the operation of stage groups under off-design conditions instead of physical experiment, seems to be attractive. The application of this idea for impulse type turbine stage groups was presented in different works. Here we discuss similar results but obtained for reaction type turbine stage groups, that is: - mathematical model for computer simulation of operation of reaction type turbine stage group, under variable regime (based on Ainley's and Mathieson's method with some improvements); - simulation results for a number of stage groups designed according to former BBC and traditional concept; - more general properties of these groups (in relation to flow capacity and efficiency) obtained form the analysis of simulation data; - comparison of observed properties of impulse and reaction type turbine stage groups.
PL
Znajomość charakterystyk grup stopni turbinowych jest stale jeszcze niewystarczająca, zwłaszcza w ogólnym przypadku zmian warunków pracy. Stan ten jest spowodowany szczupłością dostępnych danych doświadczalnych. W tej sytuacji atrakcyjne staje się wykorzystanie możliwości uzyskania potrzebnych danych przez modelowanie matematyczne i symulację cyfrową pracy grupy stopni w zmienionych warunkach, zamiast z eksperymentu fizycznego. Zastosowanie tej koncepcji w przypadku grupy stopni turbinowych budowy komorowej ("akcyjnych") przedstawiono w innych pracach. Tutaj dyskutowane są podobne wyniki, otrzymane dla grup reakcyjnych stopni turbinowych (budowy bębnowej) tj.: - model matematyczny dla symulacji pracy grup reakcyjnych stopni turbinowych w zmienionych warunkach (oparty na metodzie Ainley'a i Mathieson'a z pewnymi ulepszeniami); - wyniki symulacji dla szeregu grup stopni zaprojektowanych wg koncepcji byłej wytwórni BBC oraz "tradycyjnych" zasad; - ogólniejsze właściwości tych grup (odnośnie przelotności i sprawności) otrzymane w wyniku analizy danych z symulacji; - porównanie zaobserwowanych właściwości grup stopni typu "akcyjnego" i "reakcyjnego".
16
Content available remote Analysis on turbine stage reaction efficiency influence
Zariankin A. E., Koshkin S. V.
Zeszyty Naukowe. Cieplne Maszyny Przepływowe - Turbomachinery / Politechnika Łódzka
|
1999
|
nr 115
499--506
EN
The key characteristic of a turbine stage is its reaction rate, which defines not only the stage efficiency, but also effects the flow passage design in multi-stage turbine. The submitted report presents the influence of the efficiency reaction and analysis the loss of velocity coefficients in blades. This influence is essentially less in the active stages and is small in stages with negative reaction. In the last case an optimal thermal drop of a stage is decisively increased and an opportunity arises to reduce dimensions of multi-stages turbines under the acceptable decrease of maximum efficiency of a turbine, from the technical stand point.
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