scholarly journals Blade Row Interaction in a Multistage Low-Pressure Turbine

1991 ◽  
Author(s):  
N. Arndt
Keyword(s):  
Rotor Blade ◽  
Low Pressure ◽  
Turbine Rotor ◽  
Secondary Flows ◽  
Rotor Wake ◽  
Low Pressure Turbine ◽  
Wake Turbulence ◽  
Blade Row ◽  
Flow Phenomena ◽  
Flow Through

The objective of this work was to enhance the understanding of unsteady flow phenomena in multistage low-pressure turbines. For this purpose, hot-film probe measurements were made downstream of every rotor blade row of a five-stage low-pressure turbine. Rotor-rotor interaction and stator-rotor interaction were observed to have a profound influence on the flow through the low-pressure turbine. Interaction of rotors of different turbine stages occurred owing to the influence of the wakes shed by one rotor blade row upon the flow through the next downstream rotor blade row. This wake-induced rotor-rotor interaction resulted in strongly amplitude-modulated periodic and turbulent velocity fluctuations downstream of every rotor blade row with the exception of the most upstream one. Significantly different wake depths and turbulence levels measured downstream of every rotor blade row at different circumferential positions evidenced the effect of the circumferentially nonuniform stator exit flow upon the next downstream rotor blade row. Stator-rotor interaction also strongly influenced the overturning and the underturning of the rotor wakes, caused by the rotor secondary flows, in the rotor endwall regions. Low rotor wake overturning and underturning, i.e., reduced rotor secondary flow influence, were observed to correlate well with low rotor wake turbulence levels.

Blade Row Interaction in a Multistage Low-Pressure Turbine

1993 ◽  
Vol 115 (1) ◽  
pp. 137-146 ◽  
Author(s):  
N. Arndt
Keyword(s):  
Rotor Blade ◽  
Low Pressure ◽  
Turbine Rotor ◽  
Secondary Flows ◽  
Rotor Wake ◽  
Low Pressure Turbine ◽  
Wake Turbulence ◽  
Blade Row ◽  
Flow Phenomena ◽  
Flow Through

The objective of this work was to enhance the understanding of unsteady flow phenomena in multistage low-pressure turbines. For this purpose, hot-film probe measurements were made downstream of every rotor blade row of a five-stage low-pressure turbine. Rotor–rotor interaction and stator–rotor interaction were observed to have a profound influence on the flow through the low-pressure turbine. Interaction of rotors of different turbine stages occurred owing to the influence of the wakes shed by one rotor blade row upon the flow through the next downstream rotor blade row. This wake-induced rotor–rotor interaction resulted in strongly amplitude-modulated periodic and turbulent velocity fluctuations downstream of every rotor blade row with the exception of the most upstream one. Significantly different wake depths and turbulence levels measured downstream of every rotor blade row at different circumferential positions evidenced the effect of the circumferentially nonuniform stator exit flow upon the next downstream rotor blade row. Stator-rotor interaction also strongly influenced the overturning and the under-turning of the rotor wakes, caused by the rotor secondary flows, in the rotor endwall regions. Low rotor wake overturning and underturning, i.e., reduced rotor secondary flow influence, were observed to correlate well with low rotor wake turbulence levels.

Investigation of the Impact of Unsteady Turbulence Effects on the Aeroelastic Analysis of a Low-Pressure Turbine Rotor Blade

2019 ◽  
Vol 141 (10) ◽  
Author(s):  
Jan Philipp Heners ◽  
Damian M. Vogt ◽  
Christian Frey ◽  
Graham Ashcroft
Keyword(s):  
Rotor Blade ◽  
Numerical Study ◽  
Turbulence Models ◽  
Gibbs Phenomenon ◽  
Low Pressure ◽  
Turbine Rotor ◽  
Filter Method ◽  
Turbine Rotor Blade ◽  
Low Pressure Turbine ◽  
The Impact

Abstract The impact of the unsteadiness in the considered turbulence quantities on the numerical prediction of the aeroelastic behavior of a low-pressure turbine (LPT) rotor blade is evaluated by means of a numerical study. In this context, one of the main objectives of this work is to compare different nonlinear harmonic balance (HB) approaches—one neglecting and one considering the unsteadiness in the employed turbulence models—with a conventional nonlinear solver of the unsteady Reynolds-averaged Navier–Stokes (URANS) equations in the time domain. In order to avoid unphysical oscillations in the turbulence quantities caused by the Gibbs phenomenon in the chosen HB approach, a filter method based on the Lanczos filter is developed. The developed filter method is applied in the course of the HB simulations considering the unsteadiness in the underlying turbulence model. Furthermore, the impact of its application on the solution of the flow field and on the unsteady surface pressure of the rotor blade, in particular, is discussed in the context of this work.

Non-Axisymmetric Endwall Profiling in a Turbine Rotor Blade

1998 ◽  
Author(s):  
J. C. Hartland ◽  
D. G. Gregory-Smith ◽  
M. G. Rose
Keyword(s):  
Rotor Blade ◽  
Pressure Field ◽  
Substantial Reduction ◽  
Three Dimensional ◽  
Turbine Rotor ◽  
Secondary Flows ◽  
Linear Cascade ◽  
Turbine Rotor Blade ◽  
Blade Row ◽  
Edge Location

A non-axisymmetric endwall profile has been designed using CFD with the aim of reducing endwall pressure non-uniformities downstream of a rotor blade. The purpose was to reduce coolant leakage as proposed by Rose (1994). This profile has been manufactured and fitted to the Durham linear cascade. The experimental endwall pressure distribution agrees very well with the CFD predictions giving a substantial reduction in pressure non-uniformity at the equivalent of the platform edge location downstream. Velocity and total pressure measurements have also been made within and downstream of the blade row to investigate the effects of the profile on the cascade secondary flow. Although the experimental results indicate no significant increase in the secondary flows, a small increase in loss is seen. The CFD predicts these trends also but to a smaller extent. This investigation suggests that with three-dimensional endwall design, the pressure field which provides the driving force of secondary flows can be modified without blade redesign.

Failure of a low pressure turbine rotor blade of an aeroengine

2006 ◽  
Vol 13 (8) ◽  
pp. 1202-1219 ◽  
Author(s):  
S.K. Bhaumik ◽  
M. Sujata ◽  
M.A. Venkataswamy ◽  
M.A. Parameswara
Keyword(s):  
Rotor Blade ◽  
Low Pressure ◽  
Turbine Rotor ◽  
Turbine Rotor Blade ◽  
Low Pressure Turbine

Influence of Hot Streak Temperature Ratio on Low Pressure Stage of a Vaneless Counter-Rotating Turbine

2007 ◽  
Author(s):  
Qingjun Zhao ◽  
Fei Tang ◽  
Huishe Wang ◽  
Jianyi Du ◽  
Xiaolu Zhao ◽  
...  
Keyword(s):  
Shock Wave ◽  
High Pressure ◽  
Secondary Flow ◽  
Low Pressure ◽  
Turbine Rotor ◽  
Temperature Ratio ◽  
High Pressure Turbine ◽  
Pressure Stage ◽  
Low Pressure Turbine ◽  
Hot Streak

In order to explore the influence of hot streak temperature ratio on low pressure stage of a Vaneless Counter-Rotating Turbine, three-dimensional multiblade row unsteady Navier-Stokes simulations have been performed. The predicted results show that hot streaks are not mixed out by the time they reach the exit of the high pressure turbine rotor. The separation of colder and hotter fluids is observed at the inlet of the low pressure turbine rotor. After making interactions with the inner-extending shock wave and outer-extending shock wave in the high pressure turbine rotor, the hotter fluid migrates towards the pressure surface of the low pressure turbine rotor, and the most of colder fluid migrates to the suction surface of the low pressure turbine rotor. The migrating characteristics of the hot streaks are predominated by the secondary flow in the low pressure turbine rotor. The effect of buoyancy on the hotter fluid is very weak in the low pressure turbine rotor. The results also indicate that the secondary flow intensifies in the low pressure turbine rotor when the hot streak temperature ratio is increased. The effects of the hot streak temperature ratio on the relative Mach number and the relative flow angle at the inlet of the low pressure turbine rotor are very remarkable. The isentropic efficiency of the Vaneless Counter-Rotating Turbine decreases as the hot streak temperature ratio is increased.

Premature Fatigue Failures in the Hot Zone of Low Pressure Turbine Rotor (LPTR) Blades of Aero-Engine

2017 ◽  
pp. 65-76
Author(s):  
M. Madan ◽  
R. Bharathanatha Reddy ◽  
K. Raghavendra ◽  
M. Sujata ◽  
S. K. Bhaumik
Keyword(s):  
Low Pressure ◽  
Turbine Rotor ◽  
Low Pressure Turbine ◽  
Aero Engine ◽  
Fatigue Failures ◽  
Hot Zone

The Influence of Different Rim Seal Geometries on Hot-Gas Ingestion and Total Pressure Loss in a Low-Pressure Turbine

2010 ◽  
Author(s):  
P. Schuler ◽  
W. Kurz ◽  
K. Dullenkopf ◽  
H.-J. Bauer
Keyword(s):  
Pressure Loss ◽  
Total Pressure ◽  
Gas Flow ◽  
Low Pressure ◽  
Total Pressure Loss ◽  
Pressure Loss Coefficient ◽  
Low Pressure Turbine ◽  
Hot Gas ◽  
Flow Through ◽  
Total Pressure Loss Coefficient

In order to prevent hot-gas ingestion into the rotating turbo machine’s inside, rim seals are used in the cavities located between stator- and rotor-disc. The sealing flow ejected through the rim seal interacts with the boundary layer of the main gas flow, thus playing a significant role in the formation of secondary flows which are a major contributor to aerodynamic losses in turbine passages. Investigations performed in the EU project MAGPI concentrate on the interaction between the sealing flow and the main gas flow and in particular on the influence of different rim seal geometries regarding the loss-mechanism in a low-pressure turbine passage. Within the CFD work reported in this paper static simulations of one typical low-pressure turbine passage were conducted containing two different rim seal geometries, respectively. The sealing flow through the rim seal had an azimuthal velocity component and its rate has been varied between 0–1% of the main gas flow. The modular design of the computational domain provided the easy exchange of the rim seal geometry without remeshing the main gas flow. This allowed assessing the appearing effects only to the change of rim seal geometry. The results of this work agree with well-known secondary flow phenomena inside a turbine passage and reveal the impact of the different rim seal geometries on hot-gas ingestion and aerodynamic losses quantified by a total pressure loss coefficient along the turbine blade. While the simple axial gap geometry suffers considerable hot-gas ingestion upstream the blade leading edge, the compound geometry implying an axial overlapping presents a more promising prevention against hot-gas ingestion. Furthermore, the effect of rim seals on the turbine passage flow field has been identified applying adequate flow visualisation techniques. As a result of the favourable conduction of sealing flow through the compound geometry, the boundary layer is less lifted by the ejected sealing flow, thus resulting in a comparatively reduced total pressure loss coefficient over the turbine blade.

Application of GE Low Load Package on an Existing District Heating Power Plant: A Case Study

2020 ◽  
Author(s):  
Antonio Mambro ◽  
Francesco Congiu ◽  
Francesco Piraccini
Keyword(s):  
Power Plant ◽  
Power Plants ◽  
District Heating ◽  
Low Pressure ◽  
Heating Power ◽  
Low Pressure Turbine ◽  
Low Load ◽  
Flow Through ◽  
Last Stage

Abstract The continuous increase of variable renewable energy and fuel cost requires steam turbine power plants to operate with high flexibility. Furthermore, the reduction in electricity price is forcing many existing and new district heating power plants to further optimize the heat production to maintain a sustainable business. This situation leads to low pressure steam turbines running at very low volume flow for an extended time. In this work, a case study of an existing 30 MWel district heating power plant located in Europe is presented. The customer request was the removal of the steam turbine last two stages along with the condenser to maximize steam delivery for district heating operations. However, based on the experience gained by GE on low load during the last years, the same heat production has been guaranteed without any significant impact on the existing unit, excluding any major modification of the plant layout such as last stage blading and condenser removal. Making use of the latest low flow modeling, the minimum cooling flow through the low-pressure turbine has been reduced by more than 90% compared to the existing unit. Optimization of the hood spray system and logic will reduce trailing edge erosion during low load operation leading to a significant extension in the last stage blade lifetime. These modifications, commercialized by GE as the Advanced Low Load Package (ALLP), provide a cheap, flexible and effective solution for the customer. With today’s knowledge, GE has the capability to guarantee low load operation minimizing the mass flow through the low-pressure turbine to the minimum required for safe operation. As a benefit to the customer, this option allows a gain in operational income of about 1.5 M€ per year.

scholarly journals Investigation of parts assembly error, taking into account the deviation of the shape of their surfaces

2018 ◽  
Vol 224 ◽  
pp. 01098 ◽  
Author(s):  
Mikhail Bolotov ◽  
Iliya Grachev ◽  
Evgeny Kudashov
Keyword(s):  
Computer Model ◽  
Low Pressure ◽  
Turbine Rotor ◽  
Low Pressure Turbine ◽  
Geometrical Errors ◽  
Study Results ◽  
Assembly Unit ◽  
Assembly Error

In this article, we study the errors in the assembly of parts, taking into account the deviation of the shape of their surfaces. The developed computer model of the assembly of the engine low-pressure turbine rotor is designed to predict the values of the assembly parameters, such as radial and face run-out. The forecasting of the above assembly parameters is carried out based on the data of actual dimensions and shape of the surfaces of parts assembled as an assembly unit. The analysis of study results made it possible to obtain a conclusion about the qualitative influence of geometrical errors of the assembled parts on the error of the assembly parameters.

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