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.

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

scholarly journals Numerical Study of Flutter Stabilization in Low Pressure Turbine Rotor with Intentional Mistuning

2018 ◽  
Vol 148 ◽  
pp. 98-105 ◽  
Author(s):  
Sara Biagiotti ◽  
Lorenzo Pinelli ◽  
Francesco Poli ◽  
Federico Vanti ◽  
Roberto Pacciani
Keyword(s):  
Numerical Study ◽  
Low Pressure ◽  
Turbine Rotor ◽  
Low Pressure Turbine

Effect of Struts Downstream of Low Pressure Turbine on Tone Noise Generation

2020 ◽  
Author(s):  
Ravil Nigmatullin ◽  
Larisa Terenteva
Keyword(s):  
Stokes Equations ◽  
Numerical Study ◽  
Pressure Fluctuations ◽  
Three Dimensional ◽  
Maximum Amplitude ◽  
Low Pressure ◽  
Mode Analysis ◽  
Low Pressure Turbine ◽  
Noise Characteristics ◽  
The Impact

Abstract In the present work a numerical study of tone noise generated by the last stage of the Low Pressure Turbine (LPT) of an aircraft engine designed for a medium-haul civilian aircraft has been conducted. The impact of struts on the tone noise characteristics is estimated. The method for turbine noise calculation is based on numerical integration of the three-dimensional unsteady Reynolds averaged Navier-Stokes equations using an in-house code for multi-stage simulations. To obtain the tonal characteristics of the generated noise, the pressure pulsation field is processed using the methods of radial mode analysis. The calculated pressure fluctuations contain all possible components of the frequency-modal spectrum, which allows us to determine profile of the generated tone noise and find propagating modes with maximum amplitude. The calculations showed that the presence of struts leads to a scattering effect, which manifests as an increase in the number of generated circumferential modes. These circumferential modes propagate both downstream and upstream and increase the total level of tone noise. The amplitudes of circumferential modes related to two different types of the interaction, rotor-stator and rotor-struts, are compared.

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.

Performance Considerations in Replacement of Low-Pressure Turbine Rotors for Nuclear Power Plants: A Case Study

2005 ◽  
Author(s):  
Komandur S. Sunder Raj
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Low Pressure ◽  
Turbine Rotor ◽  
Modeling Tools ◽  
Low Pressure Turbine ◽  
Turbine Rotors ◽  
The Impact

In recent years, the nuclear power industry has witnessed profound changes in terms of renewal of operating licenses and power uprates. Renewal of operating licenses for an additional 20 years beyond the original licensed period of 40 years entails several considerations relating to aging management, performance, reliability, availability, and maintainability. Power uprates range from a low of up to 2% due to improved techniques in feedwater flow measurement to a high of up to 20% for extended power uprates. Since the limitations of power uprates are generally encountered in design of the turbine cycle, the impact upon the performance, reliability, availability and maintainability of the equipment and components in the turbine cycle may vary from low or moderate to significant. Several nuclear power plant owners have already replaced the low-pressure turbine rotors of their nuclear units with improved designs to mitigate blade failures and forced outages due to stress corrosion cracking, to reduce inspection intervals and maintenance, achieve higher output due to improved efficiency, etc. Others are either embarking upon or planning similar initiatives to confront aging, performance, availability, reliability and maintainability concerns stemming from renewal of operating licenses as well as the need to accommodate higher pressures and flows accompanying the proposed power uprates. Typically, the original low-pressure turbine designs utilizing built-up rotors with shrunk-on disks are being replaced with monoblock rotors with fully integral disks, couplings, blading and shrouds. The last stage blading is also longer resulting in a larger annulus area. Since these replacement programs involve significant expenditures, several factors need to be considered in order to ensure that the objectives of the rotor replacement programs are met. Using a case study, this paper examines the various considerations involved in replacing the low-pressure turbine rotors for a nuclear power plant. Design, performance and test considerations that need to be addressed before and after the low-pressure turbine rotors are replaced are discussed. The use of performance modeling tools in evaluating performance gains from low-pressure turbine rotor replacements is reviewed. Finally, the paper provides recommendations for ensuring that the objectives of a low-pressure turbine rotor replacement program are met.

Toward Improved Film Cooling Prediction

2002 ◽  
Vol 124 (2) ◽  
pp. 193-199 ◽  
Author(s):  
G. Medic ◽  
P. A. Durbin
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Film Cooling ◽  
Rotor Blade ◽  
Energy Production ◽  
Turbulence Models ◽  
Turbine Rotor ◽  
Turbulence Energy ◽  
Turbine Rotor Blade ◽  
Flow And Heat Transfer

Computations of flow and heat transfer for a film-cooled high pressure gas turbine rotor blade geometry are presented with an assessment of several turbulence models. Details of flow and temperature field predictions in the vicinity of cooling holes are examined. It is demonstrated that good predictions can be obtained when spurious turbulence energy production by the turbulence model is prevented.

Tip-Shroud Labyrinth Seal Effect on the Flutter Stability of Turbine Rotor Blades

2019 ◽  
Vol 141 (10) ◽  
Author(s):  
Roque Corral ◽  
Michele Greco ◽  
Almudena Vega
Keyword(s):  
Rotor Blade ◽  
Labyrinth Seal ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Labyrinth Seals ◽  
Turbine Rotor Blade ◽  
The Stability ◽  
Shrouded Rotor ◽  
Tip Shroud ◽  
The Impact

Abstract The effect of the tip-shroud seal on the flutter onset of a shrouded turbine rotor blade, representative of a modern gas turbine, is numerically tested, and the contributions to the work per cycle of the aerofoil and the tip shroud are clearly identified. The numerical simulations are conducted using a linearized frequency-domain solver. The flutter stability of the shrouded rotor blade is evaluated for an edgewise mode and compared with the standard industrial approach of not including the tip-shroud cavity. It turns out that including the tip shroud significantly changes the stability prediction of the rotor blade. This is due to two facts. First, the amplitude of the unsteady pressure created in the inter-fin cavity due to the motion of the airfoil is much greater than that of the airfoil. The impact of this contribution increases with the frequency. Second, the effect of the outer shroud of the rotor blade, which usually is not included either in the simulations, has an opposite trend with the nodal diameter than the airfoil reducing the maximum and minimum damping. It is concluded that the combined effect of the seal and its platform tends to stabilize the edgewise mode of the rotor blade for all the examined nodal diameters and reduced frequencies. Finally, the numerical results are shown to be consistent with those obtained using an analytical simplified model to account for the effect of the labyrinth seals.

3D Woven Carbon/Glass Hybrid Spar Cap for Wind Turbine Rotor Blade

2006 ◽  
Vol 128 (4) ◽  
pp. 562-573 ◽  
Author(s):  
Mansour H. Mohamed ◽  
Kyle K. Wetzel
Keyword(s):  
Wind Turbine ◽  
Carbon Fibers ◽  
Rotor Blade ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Constant Thickness ◽  
Turbine Rotor Blade ◽  
Parametric Studies ◽  
The Impact ◽  
Wind Turbine Rotor

This paper presents the design and analysis for a spar cap for a wind turbine rotor blade. The cap is formed of an integral, unitary 3D woven material (3WEAVE®) having constant thickness; spar cap weight is varied and controlled by appropriately tapering the cap width from the blade root to tip. This analysis is employed for 24-m and 37-m rotor blades. These studies are conducted parametrically, examining a range of 3WEAVE® materials incorporating varying fractions of glass and carbon fibers, and hence exhibiting a range of structural properties and material costs. These parametric studies are used to determine the impact on blade weight and cost resulting from the various materials studied. Detailed results are presented in the form of tables to enable candidate materials to be evaluated as they are developed.

Surface Roughness Impact on Low-Pressure Turbine Performance due to Operational Deterioration

2017 ◽  
Author(s):  
Andreas Kellersmann ◽  
Sarah Weiler ◽  
Christoph Bode ◽  
Jens Friedrichs ◽  
Jörn Städing ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Laser Scanning ◽  
Numerical Study ◽  
Pressure Ratio ◽  
Turbine Blades ◽  
Low Pressure ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Low Pressure Turbine ◽  
The Impact

The overall efficiency and operational behavior of aircraft engines are influenced by the surface finish of the airfoils. During operation, the surface roughness significantly increases due to erosion and deposition processes. The aim of this study is to analyze the influence of roughness on the aerodynamics of the low-pressure turbine of a mid-sized high bypass turbofan. In order to gain a better insight into the operational roughness structures, a sample of new, used, cleaned and reworked turbine blades and vanes are measured using the confocal laser scanning microscopy technique. The measurement results show local inhomogeneities. The roughness distributions measured are then converted into their equivalent sand grain roughness ks,eq to permit an evaluation of the impact on aerodynamic losses. The numerical study is performed using the CFD-solver TRACE which was validated before with existing data from Rig experiments. It is observed that the influence of the surface roughness on the turbine efficiency is significant at take-off but negligible at cruise. A detailed analysis on the aerodynamics at take-off shows that very rough airfoils lead to higher profile and secondary loss. Due to the higher disturbances present in flows circulating over rough walls, the transition occurs earlier and the momentum thickness increases in the turbulent boundary layer. The service-induced roughness structures cause an efficiency drop in the low pressure turbine of ηT = −0.16% compared to new parts. A gas path analysis showed that this results in an increased fuel flow of Δṁf = +0.06% and an exhaust gas temperature rise of ΔEGT = +1.2K for fixed engine pressure ratio which is equivalent to roughly 4 percent of the typical EGT margin of a fully refurbished engine. This result stresses the importance of roughness induced loss in low pressure turbines.

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