Wyniki wyszukiwania - BazTech

1

Development of flow and efficiency characteristics of an axial compressor with an analytical method including cooling air extraction and variable inlet guide vane angle

Trawiński Paweł

Archives of Thermodynamics

|

2021

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Vol. 42, no 4

17--46

EN

The development of a reliable mathematical model of an axial compressor requires applying flow and efficiency characteristics. This approach provides performance parameters of a machine depending on varying conditions. In this paper, a method for developing characteristics of an axial compressor is presented, based on general compressor maps available in the literature or measurement data from industrial facilities. The novelty that constitutes the core of this article is introducing an improved method describing the performance lines of an axial compressor with the modified ellipse equation. The proposed model is extended with bleed air extraction for the purposes of cooling the blades in the expander part of the gas turbine. The variable inlet guide vanes angle is also considered using the vane angle correction factor. All developed dependencies are fully analytical. The presented approach does not require knowledge of machine geometry. The set of input parameters is based on reference data. The presented approach makes it possible to determine the allowed operating area and study the machine’s performance in variable conditions. The introduced mathematical correlations provide a fully analytical study of optimum operating points concerning the chosen criterion. The final section presents a mathematical model of an axial compressor built using the developed method. A detailed study of the exemplary flow and efficiency characteristics of an axial compressor operating with a gas turbine is also provided.

2

Influence of Axial Compressor Model Simplification and Mesh Density on Surge Margin Evaluation

Muchowski Rafał, Gubernat Sławomir Maciej

Advances in Science and Technology. Research Journal

|

2021

|

Vol. 15, no 3

243--253

EN

The menace of surge occurrence in the compressors is taken very seriously and its avoidance became a fundamental for the design of any modern jet engines. Nowadays, a problem with appropriate evaluation of the compressor surge margin while considering different simplifications of three-dimensional CFD model is still present. For that purpose, this article presents a comparison between the measurement data and several variants of 3D CFD models characterized by a specific mesh density. To calculate all the results on which the comparisons and conclusions are based, an 8-stage axial compressor is taken into account. Flow conditions of the machine are computed for three part load speeds: The low, the mid and the high one respecting the variable guide vanes schedule fitted to the specific load. For each of speed variants a four mesh configurations were generated: coarse, medium, fine and extra-fine. All speed configurations were treated with two different turbulence models – Wilcox k-ω and Menter’s SST k-ω, giving ultimately 15 CFD models, calculated with the TRACE solver using an initialization based on a circumferentially averaged flow solution delivered by the Streamline Curvature Method. During the study an additional assessment of reference grid independence was performed and the mesh convergence has been achieved. A comparison between turbulence models and the measurement proves that SST turbulence model is not well distributed through the speeds in compare to the measurement data and the Wilcox turbulence model. Inconsistency of sensitivity in the mesh coarsening for different rotational speeds was found. Increasing the mesh roughness level has to be executed for each speed separately. Overall compressor map shows that shift of the Pressure Ratio and the Mass Flow decreases with lower rotational speed. Neglecting the system add-ons like labyrinth sealing volumes, bleed-ports and other leakages has a visible influence on deviations from the measurements. Because of intended future use in design and optimization the “Medium” grid with Wilcox k-ω turbulence model was chosen, being a good representation of the Rig characteristics with reduction of the computing time.

3

Zastosowanie sztucznych sieci neuronowych do obliczeń wytrzymałościowych maszyn wirnikowych

Kozakiewicz A., Kieszek R.

Przegląd Mechaniczny

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2018

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nr 9

28--30

PL

W artykule przedstawiono wyniki badań numerycznych nad możliwością zastosowania sztucznych sieci neuronowych (SSN) do obliczeń wytrzymałościowych elementów maszyn wirnikowych. W tym celu autorzy rozważyli kilka prostszych przypadków w celu ustalenia optymalnej struktury SSN i odpowiedniego sposobu jej uczenia. W pracy przedstawiono wyniki dotyczące uczenia sieci rozwiązywania problemu belki wysięgnikowej. Następnie analizowano problem ważkiej tarczy prostej obciążonej ciągnieniem w celu doboru modelu SSN. Ostatnim analizowanym zagadnieniem było zastosowanie SSN do wyznaczania rozkładu naprężeń w profilowanej tarczy sprężarki osiowej.

EN

In this paper the results of numerical research in possibility of usage artificial neural network (ANN) in stresses analysis are presented. For this purpose, a few simple cases were considered in order to optimize the ANN structure and its learning algorithm. In the first part of this paper, results of learning ANN of solving the cantilevered beam problem are shown. The simplified compressor disc problem was analyzed due to select the ANN model. The last case is the use of ANN to stresses analysis of profiled axial compressor disc.

4

Investigation of inlet distortion effects on axial compressor performance based on streamline curvature method

Abbasi S., Pirnia A., Taghavi-Zenouz R.

Journal of Theoretical and Applied Mechanics

|

2018

|

Vol. 56 nr 4

1005--1015

EN

In this paper, the effects of inlet flow distortion on performance maps and details of the flow field are investigated using the Streamline Curvature Method. The results are presented for both design and off-design conditions and compared with experimental data, which shows good agreement. The effects of inlet flow distortion are investigated by inlet total pressure variation in three different cases in the way that the average total pressure remains constant and equal to the design value. The results show that a relative increase in the total pressure at tip causes an increase in the pressure ratio and efficiency as well as a better performance in the choking region. Alternatively, a relative increase in the total pressure in hub causes opposite behavior and a better performance at the surging region.

5

Factors influencing axial compressor stalls

Laskowski P.

Zeszyty Naukowe. Transport / Politechnika Śląska

|

2017

|

z. 95

89--96

EN

The article describes the problem regarding stalls in axial compressors, which are widely used in the engines of large and very large transportation aircrafts. The stall phenomenon, unless cleared, poses a major danger to the integrity of a compressor module, which in turn may result in uncontained engine failure and loss of thrust, thereby seriously affecting flight safety. The costs of maintenance to be performed may also be very high, due to irreversible deterioration in some components. A practical assessment of the stall problem and its countermeasures are discussed below.

6

Numerical loss analysis on slot-type casing treatment in a transonic compressor stage

Zhu M.-M., Qiang X.-Q., Teng J.-F.

Journal of Theoretical and Applied Mechanics

|

2017

|

Vol. 55 nr 1

293--306

EN

To understand the loss mechanism of slot-type casing treatment, a numerical loss analysis has been carried out in a 1.5 axial transonic compressor stage with various slots. Spanwise and streamwise distribution curves of pitch-averaged entropy have been presented to survey the development of loss generation. Further, detailed entropy distributions at eight axial cuts, which have been taken through the blade row and slots, have been further analyzed to interpret the loss mechanism. The most dramatic loss growth occurred above 95% span, which directly resulted from slots injection flow upstream the leading edge. Loss generations with smooth casing have been primarily ascribed to low-momentum tip leakage flow/vortex and suction surface separation at the leading edge. CU0 slot, the arc-curved slots with 50% rotor tip exposure, has been capable of suppressing the suction surface separation loss. Meanwhile, accelerated tip leakage flow brought about additional loss near the casing and pressure surface. Upstream high entropy flow would be absorbed into the rear portion of slots repeatedly, which resulted in further loss.

7

Parametry określające wejście lotniczego silnika turbinowego w niestateczną pracę sprężarki

Kozakiewicz A., Kowalski M.

Prace Instytutu Lotnictwa

|

2016

|

Nr 3 (244)

373--384

PL

W artykule przedstawiono przyczyny generowania nierównomiernego pola parametrów na wejściu do sprężarki lotniczego silnika turbinowego i ich wpływ na kinematykę strumienia powietrza przy obniżającej się wytrzymałości zmęczeniowej łopatki sprężarkowej. Dokonano analizy przebiegu zmian momentu obrotowego wirnika jako funkcji czasu. Przedstawiono przebiegi podstawowych parametrów pracy silnika turbinowego podczas wchodzenia w zakres niestatecznej pracy. Określono istotną rolę w tej ocenie zmian pierwszej pochodnej momentu obrotowego w relacji do zmian przyspieszeń wirnika, która może być istotnym sygnałem o możliwości wystąpienia pompażu w sprężarce. Parametr ten może być sygnałem dla układu sterowania do eliminowania tego szkodliwego zjawiska. Przedstawiono także dynamikę silnika wspartą badaniem podczas pompażu poprzez opracowanie portretów fazowych podstawowych parametrów jego pracy. Artykuł zawiera analizę dynamiki zmian temperatury spalin.

EN

This paper presents reasons for generating non uniform area of parameters on the entry to the compressor of the turbine engine and their influence on the air stream kinematics at the decreasing fatigue strength of the compressor blade. Analysis of the course of the torque rotor changes as the function of time was presented. Courses of basic parameters of the turbine engine work during the ingress into the range of unstable work were presented. The crucial role in this estimation of changes of the first differential of the torque in relation to changes in acceleration of the rotor which can be a significant signal of the possibility of surge occurrence in the compressor were defined. This parameter can be a signal for the control system to eliminate this bad phenomenon. The dynamics of the engine supported with the research during surge through the study of parameters'phase portraits of its work were also presented. The article contains analysis of the dynamics of changes in temperature of combustion gas.

8

Estymacja punktu pracy sprężarki i jego parametrów w oparciu o charakterystyki sprężarek

Kozakiewicz A.

Prace Instytutu Lotnictwa

|

2016

|

Nr 3 (244)

363--372

PL

W artykule przedstawiono problematykę związaną z estymacją punktu pracy sprężarki w oparciu ojej charakterystykę. Analizowano problematykę związaną z pracą poszczególnych stopni zespołu ze względu zmiany kąta natarcia strumienia w wyniku zmian prędkości obrotowych. Przedstawiono wyniki analizy numerycznej opływu stopnia sprężarki. Zanalizowano zmianę położenia linii pracy silnika w wyniku wyboru kąta natarcia na zakresie obliczeniowym. Zaprezentowano problematykę ze zmianą warunków pracy poszczególnych stopni sprężarki.

EN

This paper presents problems concerning the estimation of the point works of the compressor and its parameters based on its characteristics. Problems connected with the work of individual compressor stages regarding the change of the angle of attack stream as a result of changes in rotating velocities were analysed Results of the numerical analysis of the stage compressor's round flow were demonstrated. The- dislocation of the work line of the engine as a result of the choice of the angle of attack on the computational range were presented. Problems with modifying work conditions for individual compressor stages were presented.

9

Mathematical modeling of an axial compressor in a gas turbine cycle

Plis M., Rusinowski H.

Journal of Power Technologies

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2016

|

Vol. 96, nr 3

194--199

EN

Contemporary thermal diagnostic systems of power units require advanced computational tools, including mathematical models. These models should have a simple structure and short computing time. These conditions are satisfied by models that include mass and energy balances as well as additional empirical functions whose coefficients are estimated by using the measurement results. This paper presents a simulation model of an axial compressor which forms part of a gas turbine unit with a rated output of 125.4 MW. The model was developed with the use of a generalized compressor map, describing the relationship between corrected air mass flow rate, pressure ratio, isentropic efficiency and corrected rotational speed. The model encompasses the empirical formula for compressor internal efficiency, which additionally considers the effect of variation of the angle of inlet guide vanes. The unknown values of empirical coefficients which appear in this equation were estimated on the basis of operating data. The calculation results obtained were compared with the measurement results. The quality of the model prediction was evaluated and conclusions were drawn.

10

Numerical study of stall inception in a transonic axial compressor rotor based on the throttle model

Zhu X., Liu B., Hu J., Shen X.

Journal of Theoretical and Applied Mechanics

|

2015

|

Vol. 53 nr 2

307--316

EN

The goal of the current paper is to investigate inner flow behavior on stall inception in a transonic compressor rotor. The stall inception process is numerically carried out by unsteady 3-D simulations based on the throttle model. The current study shows that stall starts from the tip of the blade, and stall cell extends to the axial, circumferential and radial directions. Through the comparison of flow transition characteristics at different flow rate conditions, the interface between the incoming flow and tip clearance flow shifts forward to the upstream as the mass flow decreases. Eventually, the shock detaches from the blade leading edge, and tip clearance flow spills into the adjacent blade passage, thus stall happens in the affected blade passages.

11

Multiple spike stall cells in low speed axial compressor rotor blade row

Taghavi-Zenouz R, Abbasi S.

Journal of Theoretical and Applied Mechanics

|

2015

|

Vol. 53 nr 1

47--57

EN

Inception and development of multiple stall cells of short length scales are numerically investigated in an axial compressor rotor blade row. The method of investigation is based on time accurate three-dimensional full annulus simulations. Time dependent flow structure results revealed that there are two criteria responsible for inception of a special kind of stall, introduced as spike stall in the literature. These criteria are defined as leading edge spillage and trailing edge backflow, which occur at specific mass flow rates near to stall conditions. The numerical results revealed that once the spike stall cells appear, they cover roughly two blade passages in the circumferential direction and cover about 25% of the blade height. By further revolution of the blade row, the number of cells tends to increase. For the present case study, the number of stall cells increased to three after 8.5 rotor revolutions from the moment of the initial spike stall occurrence. Even at this moment, both of the above mentioned criteria for the spike stall inception have been observed within the blades passages. These events caused the inlet relative flow angle to the blade rows, and therefore the flow incidence angle and consequent blockage to the main flow, to increase. The tip leakage flow frequency spectrum has been studied through surveying instantaneous static pressure signals imposed on pressure side of the blades and also on the casing walls. These latter results showed that any further revolving of the rotor blade row, exceeding 8.5 revolutions, causes the spike stall to disturb the flow structure significantly.

12

Investigation of Design Features of Compressor Casing Treatment

Nezym V

Archive of Mechanical Engineering

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2014

|

Vol. LXI, nr 1

153--161

EN

Obróbka obudowy kompresora, polegajacą na wykonaniu obwodowych rowków ponad szczytem łopaty wirnika, jest stosowana dla poprawy własciwosci roboczych kompresora. Zwykle rowki takie zwiekszaja zakres przeciagania kompresora (zakres stabilnego działania), ale pogarszaja sprawność. W artykule zaprezentowano główne wyniki badan nad rowkami, które wpływaja pozytywnie na sprawnosc kompresora. Badano zarówno tradycyjne (typowe) konfiguracje rowków, jak i konfiguracje ostatnio opracowane. Niektóre z nich zapewniają zarówno wzrost sprawności jak zakresu przeciągania.

13

Influence of the incorrect settings of axial compressor inlet variable stator vanes on gas turbine engine work parameters

Wirkowski P.

Journal of KONES

|

2012

|

Vol. 19, No. 3

483-489

EN

The paper deals with the problem of influence of changes variable stator vanes axial compressor settings of gas turbine engine on work parameters of compressor and engine. Incorrect operation of change setting system of variable vanes could make unstable work of compressor and engine. This paper presents theoretical analysis of situation described above and results of own research done on real engine. When in the compressor construction there is assembled system of setting change of variable stator vanes its task is to make optimal cooperation engine units during the permanent improvement of compressor characteristic. Perturbations in the operation of this system could cause changes in work of compressor and engine similarly as in the case of changes caused by changes of rotational speed or polluted interblades ducts of compressor. The purpose of investigations, which was carried out on real engine was determination influence of incorrect operation of axial compressor inlet guide variable stator vanes control system of gas turbine engine on compressor and engine work parameters. The object of research is type DR 77 marine gas turbine engine, which is a part of power transmission system of war ship. In compressor construction configuration of this engine there are used inlet guide stator vanes which make possibilities to change the setting angle incidance (change of compressor flow duct geometry) in depend on engine load. On the base of results of experiment there were determined the mathematical equations modelling the changes of particular engine work parameters in the function of variable inlet guide stator vanes setting angle.

14

Algorithm for design calculation of Axial flow gas turbine compressor - comparison with GTD-350 compressor design

Chmielniak T., Lepszy S., Rulik S.

Mechanics and Mechanical Engineering

|

2011

|

Vol. 15, nr 3

207-216

EN

The paper presents a simple algorithm for design calculation of axial flow compressor of gas turbine. The algorithm enables calculation of characteristic dimensions and gas angels in compressor stages using real gas model. Preliminary and detailed calculation base on data from GTD-350 gas turbine, also calculated and measured dimension of bleeds are compared.

15

Modelling research of the characteristics of gasturbine axial compressor with changeable flow passage geometry

Wirkowski P.

Journal of KONES

|

2011

|

Vol. 18, No. 3

507-514

EN

In real exploitational conditions marine gasturbine engine works at different rotation speeds determined by the required parameters of ship's movement. Conversion from one rotation speed to another is related to realization of unsteady energetic processes, determined by the gasodynamic mutual influence of compressor configurations. The values of working medium flow thermodynamic parameters undergo significant changes in time. To work out the qualitative and quantitative estimation of these changes it is necessary to define the dynamic equations, describing working medium flow through the gas passage of engine. In the next step it is necessary to resolve the defined equations for disturbances of steady cooperation of compressor configurations. This paper concerns the application of mathematical modelling methods to analyzing gas-dynamic processes in marine gas turbines. The influence of geometry changes in axial compressor flow passage on kinematical air flow characteristics is presented. The elaborated mathematical model will make it possible to realize - in the future -simulative investigations of gas-dynamic processes taking place in a compressor fitted with controllable guide vanes. Individual parametric features of every engine in service are identified by using expensive experimental tests, which are conditioned by many constructional and operational limitations. The dynamic development of computer technology, enables using it for numerical simulation of changeable technical state processes.

16

Zależność parametrów pracy silnika turbinowego od zmiany geometrii kanału przepływowego sprężarki osiowej

Wirkowski P.

Logistyka

|

2010

|

nr 4

CD-CD

PL

W artykule przedstawiono zagadnienie wpływu zmian ustawienia regulowanych łopatek kierownicy sprężarki osiowej na parametry pracy sprężarki oraz całego silnika turbinowego. Nieprawidłowe funkcjonowanie systemu zmiany ustawienia regulowanych łopatek sprężarki osiowej silnika turbinowego może powodować niestabilną pracę sprężarki przenoszoną na konstrukcję silnika. Jeżeli w konstrukcji sprężarki silnika turbinowego występuje układ zmiany ustawienia regulowanych łopatek kierownic, mający za zadanie optymalne kojarzenie współpracy wszystkich zespołów silnika turbinowego poprzez ciągłą korektę charakterystyki sprężarki, to występujące zakłócenia w pracy tego układu będą powodowały zmiany zakresu pracy sprężarki i silnika o charakterze podobnym, jaki powodują zmiany prędkości obrotowej wirnika czy też zanieczyszczone kanały międzyłopatkowe sprężarki. W artykule zaprezentowana została analiza teoretyczna powyższego zjawiska oraz przedstawiono wyniki badań przeprowadzonych na obiekcie rzeczywistym.

EN

The paper deals with the problem of influence of changes variable stator vanes axial compressor settings of gas turbine engine on work parameters of compressor and engine. Incorrect operation of change setting system of variable vanes could make unstable work of compressor and engine. This paper presents theoretical analysis of situation described above and results of own research done on real engine. On the base of results of experiment there were determined mathematical equations determining relationships of changes of particular engine work parameters in function of variable inlet guide stator vanes setting angle. There are presented results of the solution of mathematical equations, which describe the changes of engine work parameters values too.

17

Modelling research of the characteristics of gasturbine axial compressor with changeable flow passage geometry

Wirkowski P.

Logistyka

|

2010

|

nr 6

EN

One of the most important problems of exploitational use of marine gasturbine engine is knowledge about direction of changes realised unsteady processes. Individual dynamical features of each exploitated engine are determined on the way of costly experimental searches. These searches are qualified by numerous constructional and exploitational confinements. This paper concerns the application of mathematical modeling methods to analyzing gas-dynamic processes in marine gas turbines. The influence of geometry changes in axial compressor flow passage on kinematical air flow characteristics is presented. The elaborated mathematical model will make it possible to realize - in the future - simulative investigations of gas-dynamic processes taking place in a compressor fitted with controllable guide vanes.

PL

Referat dotyczy zastosowania metod modelowania matematycznego do analizy procesów gazodynamicznych w okrętowych turbinowych silnikach spalinowych. Przedstawiono wpływ zmian geometrii kanału przepływowego sprężarki osiowej na charakterystyki kinematyczne przepływającego powietrza. Opracowany model matematyczny umożliwi w przyszłości realizację badań symulujących procesy gazodynamiczne zachodzące w sprężarce wyposażonej w regulowane kierownice.

18

Modelling the characteristics of axial compressor with variable stator vanes

Wirkowski P.

Journal of KONES

|

2010

|

Vol. 17, No. 2

497-504

EN

One of the most important problems of exploitational use of marine gas turbine engine is knowledge about direction of changes realised unsteady processes. Individual dynamical features of each exploitated engine are determined on the way of costly experimental searches. These searches are qualifled by numerous constructional and exploitational confinements. In real exploitational conditions marine gasturbine engine works at different rotation speeds determined by the required parameters of ship's movement. Conversion from one rotation speed to another is related to realization of unsteady energetic processes, determined by the gasodynamic mutual influence of compressor configurations. The values of working medium flow thermodynamic parameters undergo significant changes in time. To work out the qualitative and quantitative estimation of these changes it is necessary to define the dynamic equations, describing working medium flow through the gas passage of engine. In the next step it is necessary to resohe the defined equations for disturbances of steady cooperation of compressor configurations. This paper concerns the application of mathematical modelling methods to analyzing gas-dynamic processes in marine gas turbines. The influence of geometry changes in axial compressor flow passage on kinematical air flow characteristics is presented. The elaborated mathematical model will make it possible to realize - in the future -simulative investigations of gas-dynamic processes taking place in a compressor fitted with controllable guide vanes.

19

Correlation between gas turbine engine work parameters and axial compressor flow passage geometry changes

Wirkowski P.

Logistyka

|

2009

|

nr 6

CD-CD

EN

The paper deals with the problem of influence of changes variable stator vanes axial compressor settings of gas turbine engine on work parameters of compressor and engine. Incorrect operation of change setting system of variable vanes could make unstable work of compressor and engine. This paper presents theoretical analysis of situation described above and results of own research done on real engine. On the base of results of experiment there were determined mathematical equations determining relationships of changes of particular engine work parameters in function of variable inlet guide stator vanes setting angle. There are presented results of the solution of mathematical equations, which describe the changes of engine work parameters values too.

PL

Nieprawidłowe funkcjonowanie systemu zmiany ustawienia regulowanych łopatek sprężarki osiowej silnika turbinowego może powodować niestabilną pracę sprężarki przenoszoną na konstrukcję silnika. W artykule zaprezentowana została analiza teoretyczna powyższego zjawiska oraz przedstawiono wyniki badań przeprowadzonych na rzeczywistym obiekcie. Następnie na bazie przeprowadzonych badań określone zostały równania matematyczne opisujące zależności pomiędzy wartościami rozpatrywanych parametrów pracy silnika a kątem ustawienia regulowanych łopatek. Równania te posłużyły do zasymulowania zmian wartości parametrów dla zakresu zmian kąta regulowanych łopatek nieosiągalnego podczas badań na obiekcie rzeczywistym.

20

Influence Of Axial Compressor Flow Passage Geometry Changes On Gas Turbine Engine Work Parameters

Wirkowski P.

Journal of Polish CIMAC

|

2009

|

Vol. 4, no 2

307-313

EN

The paper deals with the problem of influence of changes variable stator vanes axial compressor settings of gas turbine engine on work parameters of compressor and engine. Incorrect operation of change setting system of variable vanes could make unstable work of compressor and engine. This paper presents theoretical analysis of situation described above and results of own research done on real engine. On the base of results of experiment there were determined mathematical equations determining relationships of changes of particular engine work parameters in function of variable inlet guide stator vanes setting angle. There are presented results of the solution of mathematical equations, which describe the changes of engine work parameters values too.