Improving Characteristics of a Cooled Transonic Vane of Low Pressure Turbine Under Nonuniform Inlet Conditions

2021 ◽  
Author(s):  
Igor Afanasiev ◽  
Valery Kostezh ◽  
Evgeny Marchukov ◽  
Andrey Granovskiy
Keyword(s):  
Low Pressure ◽  
Low Pressure Turbine ◽  
Inlet Conditions

Design of an Intermediate Turbine Duct Downstream of a High Pressure Turbine

2016 ◽  
Author(s):  
Chaoshan Hou ◽  
Hu Wu
Keyword(s):  
High Pressure ◽  
Three Dimensional ◽  
Low Pressure ◽  
Aerodynamic Load ◽  
Duct Flow ◽  
Original Design ◽  
High Pressure Turbine ◽  
Intermediate Turbine Duct ◽  
Low Pressure Turbine ◽  
Inlet Conditions

The flow leaving the high pressure turbine should be guided to the low pressure turbine by an annular diffuser, which is called as the intermediate turbine duct. Flow separation, which would result in secondary flow and cause great flow loss, is easily induced by the negative pressure gradient inside the duct. And such non-uniform flow field would also affect the inlet conditions of the low pressure turbine, resulting in efficiency reduction of low pressure turbine. Highly efficient intermediate turbine duct cannot be designed without considering the effects of the rotating row of the high pressure turbine. A typical turbine model is simulated by commercial computational fluid dynamics method. This model is used to validate the accuracy and reliability of the selected numerical method by comparing the numerical results with the experimental results. An intermediate turbine duct with eight struts has been designed initially downstream of an existing high pressure turbine. On the basis of the original design, the main purpose of this paper is to reduce the net aerodynamic load on the strut surface and thus minimize the overall duct loss. Full three-dimensional inverse method is applied to the redesign of the struts. It is revealed that the duct with new struts after inverse design has an improved performance as compared with the original one.

Prediction of Separation-Induced Transition on High Lift Low Pressure Turbine Blade

2011 ◽  
Author(s):  
Abdelkader Benyahia ◽  
Lionel Castillon ◽  
Robert Houdeville
Keyword(s):  
Experimental Data ◽  
Reynolds Numbers ◽  
Low Pressure ◽  
Transition Model ◽  
Freestream Turbulence ◽  
Low Pressure Turbine ◽  
European Program ◽  
Inlet Conditions ◽  
Development And Validation ◽  
Good Agreement

This paper deals with the development and validation of the Menter and Langtry correlation-based transition model in the RANS code elsA. Two types of experimental linear cascades of low pressure turbine (LPT) airfoils having different loading distributions have been considered for the validation: the T106C and T108 blades. Experimental data have been provided by the Von Karman Institute in the framework of the European program TATMo. Different Reynolds numbers varying from 80 000 to 250 000 and different freestream turbulence intensities have been investigated. The results obtained for the T106C blade are in good agreement with the experimental data: the bubble size and the kinetic energy losses are well predicted. Sensitivity to freestream turbulence is also well demonstrated for the considered Reynolds numbers. However the results for the T108 blade show the limitations of the current version. These limitations are explained and discussed in this paper. The second part of this paper deals with the numerical and physical aspects of periodical unsteady inlet conditions which are introduced in order to take into account the incoming wakes. The original Menter and Langtry transition model has required a modification for performing correct unsteady computations of wake induced transition which is discussed in this paper. The unsteady results obtained with elsA are in quite good agreement with the experimental data.

Improving Characteristics of a Cooled Transonic Vane of Low Pressure Turbine Under Nonuniform Inlet Conditions

2020 ◽  
Author(s):  
A. V. Granovskiy ◽  
I. V. Afanasiev ◽  
V. K. Kostege ◽  
E. Yu. Marchukov
Keyword(s):  
Cooling System ◽  
Pressure Ratio ◽  
Low Pressure ◽  
Secondary Flows ◽  
Gas Temperature ◽  
Flow Angle ◽  
Low Pressure Turbine ◽  
Large Pressure ◽  
Negative Effect ◽  
Inlet Conditions

Abstract Vanes of low-pressure turbines (LPT) run under inlet conditions generated by a preceding high-pressure turbine (HPT). HP stages are generally cooled and transonic as well due to the large pressure ratio necessary to reduce the gas temperature upstream of the downstream stages. Therefore radial distributions of inlet flow angle, total pressure and total temperature at the boundary upstream of the LPT are highly non–uniform. Such non-uniform inlet conditions can result in enhanced level of the total losses including the secondary losses. Moreover, vanes of LPT have meridional openings along inner and outer boundaries of the flow path, which causes intensification of the secondary flows leading to an increase in secondary losses. In this case the special meridional contouring of the vanes’ outer and inner surfaces allows a decrease in the flare angle namely meridional opening in the rear part of the vane. In this work, in order to compensate the negative effect of non-uniform inlet conditions, meridional opening and low aspect ratio, 3D profiling of the vane row is used as a way of reducing secondary losses. Some variants of LPT vanes with various complex 3D shapes are investigated. In particular, vane variants with a “reversed bow”, a “bowed” and a “lean” in the circumferential direction have been examined. Significant modification of the vane row is limited by cooling system design, which has to incorporate a deflector in the inner hollow of the vane to improve cooling effectiveness. A compromise between aerodynamic quality and cooling limitations has been achieved.

Cracks on the Roots of Turbine Blades of the Low-Pressure Turbine in a Steam Power Plant

2015 ◽  
Vol 52 (4) ◽  
pp. 214-225 ◽  
Author(s):  
E. Plesiutschnig ◽  
R. Vallant ◽  
G. Stöfan ◽  
C. Sommitsch ◽  
M. Mayr ◽  
...  
Keyword(s):  
Power Plant ◽  
Turbine Blades ◽  
Low Pressure ◽  
Steam Power ◽  
Steam Power Plant ◽  
Low Pressure Turbine

Low-pressure turbine disc fi rtree slots’ life and reliability enhancement by ultrasonic surface hardening

2020 ◽  
pp. 491-495
Author(s):  
A.M. Tomashevich ◽  
G.G. Shirvan’yants ◽  
D.A. Teryaev
Keyword(s):  
Residual Stress ◽  
Low Pressure ◽  
Fatigue Tests ◽  
Compression Stress ◽  
Cycle Basis ◽  
Low Pressure Turbine ◽  
Working Stress ◽  
Turbine Disc ◽  
Axial Residual Stress ◽  
Reliability Enhancement

The possibility of life and reliability enhancing of AL-31F low pressure turbine disc’s fir-tree slots by ultrasonic hardening is considered. Having disc’s material properties studied, working stress derivation is executed which was further used for following comparative fatigue tests. Also, Davidenkov method residual stress analysis is carried out which showed 95.3 % change to compression stress for circumferential residual stress and 80.9 % change to compression stress for axial residual stress which proves possibility of fir-tree slots’ life and reliability enhancement by ultrasonic hardening. Comparative fatigue tests with N = 4•10 5 cycles basis showed that the hardened samples standing out the cycle basis during higher oscillatory amplitudes (and, thus, affecting loads) than the non-hardened basic ones.

scholarly journals Prediction of Transient Pressure Fluctuations within a Low-Pressure Turbine Cascade Using a Lanczos-Filtered Harmonic Balance Method

2021 ◽  
Vol 6 (3) ◽  
pp. 25
Author(s):  
Jan Philipp Heners ◽  
Stephan Stotz ◽  
Annette Krosse ◽  
Detlef Korte ◽  
Maximilian Beck ◽  
...  
Keyword(s):  
Turbulence Model ◽  
Harmonic Balance ◽  
Separation Bubble ◽  
Pressure Fluctuations ◽  
Harmonic Balance Method ◽  
Low Pressure ◽  
Filter Method ◽  
Turbine Cascade ◽  
Transient Pressure ◽  
Low Pressure Turbine

Unsteady pressure fluctuations measured by fast-response pressure transducers mounted in a low-pressure turbine cascade are compared to unsteady simulation results. Three differing simulation approaches are considered, one time-integration method and two harmonic balance methods either resolving or averaging the time-dependent components within the turbulence model. The observations are used to evaluate the capability of the harmonic balance solver to predict the transient pressure fluctuations acting on the investigated stator surface. Wakes of an upstream rotor are generated by moving cylindrical bars at a prescribed rotational speed that refers to a frequency of f∼500 Hz. The excitation at the rear part of the suction side is essentially driven by the presence of a separation bubble and is therefore highly dependent on the unsteady behavior of turbulence. In order to increase the stability of the investigated harmonic balance solver, a developed Lanczos-type filter method is applied if the turbulence model is considered in an unsteady fashion.

Interaction of Wheelspace Coolant and Main Flow in a New Aeroderivative LPT

2006 ◽  
Author(s):  
Francesco Montomoli ◽  
Michela Massini ◽  
Nicola Maceli ◽  
Massimiliano Cirri ◽  
Luca Lombardi ◽  
...  
Keyword(s):  
Flux Distribution ◽  
Low Pressure ◽  
Main Flow ◽  
Space Region ◽  
Heat Flux Distribution ◽  
Gas Generator ◽  
Component Reliability ◽  
Accuracy Requirement ◽  
Low Pressure Turbine ◽  
Hot Gas

Increased computational capabilities make available for the aero/thermal designers new powerful tools to include more geometrical details, improving the accuracy of the simulations, and reducing design costs and time. In the present work, a low-pressure turbine was analyzed, modeling the rotor-stator including the wheel space region. Attention was focused on the interaction between the coolant and the main flow in order to obtain a more detailed understanding of the behavior of the angel wings, to evaluate the wall heat flux distribution, and to prevent hot gas ingestion. Issues of component reliability related to thermal stress require accurate modeling of the turbulence and unsteadiness of the flow field. To satisfy this accuracy requirement, a full 3D URANS simulation was carried out. A reduced count ratio technique was applied in order to decrease numerical simulation costs. The study was carried out to investigate a new two-stage Low Pressure Turbine from GE Infrastructure Oil&Gas to be coupled to a new aeroderivative gas generator, the LM2500+G4, developed by GE Infrastructure, Aviation.

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