Outlet Guide Vane Airfoil for Low Pressure Turbine Configurations

2012 ◽  
Author(s):  
Helge Koch ◽  
Dragan Kozulovic ◽  
Martin Hoeger
Keyword(s):  
Guide Vane ◽  
Low Pressure ◽  
Low Pressure Turbine

Aerodynamic Effects of an Unshrouded Low Pressure Turbine on a Low Aspect Ratio Exit Guide Vane

2012 ◽  
Author(s):  
Thorsten Selic ◽  
Davide Lengani ◽  
Andreas Marn ◽  
Franz Heitmeir
Keyword(s):  
Aspect Ratio ◽  
Guide Vane ◽  
Low Pressure ◽  
Tip Clearance ◽  
Pressure Probe ◽  
Model Parameters ◽  
Leakage Flow ◽  
Low Pressure Turbine ◽  
Low Aspect Ratio ◽  
The Impact

This paper presents the effects of an unshrouded low pressure turbine (LPT) onto the following exit guide vane row (EGV). The measurement results were obtained in the subsonic test turbine facility at Graz University of Technology by means of a fast response pressure probe in planes downstream of the rotor as well as oil flow visualisation. The test rig was designed in cooperation with MTU Aero Engines and represents the last 1.5 stages of a commercial aero engine. Considerable efforts were put into the adjustment of all relevant model parameters to reproduce the full scale LPT situation. Different tip clearances were evaluated by means of CFD obtained using a commercial Navier-Stokes code and validated with experimental results. The goal is to evaluate the effect of the varying leakage flow on the flow in the low aspect ratio EGV. Special attention is given to the impact on the development of secondary flows as well as the flow structures downstream of the EGV. The effect of the leakage flow causes a change of the flow structure of the EGV, particularly losses. Considering the largest investigated tip-clearance, the losses increased by 71% when compared to a zero-leakage case.

Failure Analysis of Nozzle Guide Vane of a Low Pressure Turbine in an Aero Gas Turbine Engine

2014 ◽  
Vol 14 (5) ◽  
pp. 578-587 ◽  
Author(s):  
R. K. Mishra ◽  
Johney Thomas ◽  
K. Srinivasan ◽  
Vaishakhi Nandi ◽  
Raghavendra Bhat
Keyword(s):  
Failure Analysis ◽  
Gas Turbine ◽  
Guide Vane ◽  
Low Pressure ◽  
Gas Turbine Engine ◽  
Turbine Engine ◽  
Low Pressure Turbine ◽  
Nozzle Guide Vane ◽  
Nozzle Guide

scholarly journals Reynolds, Mach and free-stream turbulence effects on the flow in a low-pressure turbine

2021 ◽  
pp. 1-17
Author(s):  
Maxime Fiore ◽  
Nicolas Gourdain
Keyword(s):  
Reynolds Number ◽  
Mach Number ◽  
Free Stream ◽  
Guide Vane ◽  
Flow Behavior ◽  
Suction Side ◽  
Boundary Layer Separation ◽  
Low Pressure ◽  
Free Stream Turbulence ◽  
Low Pressure Turbine

Abstract This paper presents the Large Eddy Simulation of a Low-Pressure Turbine Nozzle Guide Vane for different Reynolds (Re) and Mach numbers (Ma) with or without inlet turbulence prescribed. The analysis is based on a slice of a LPT blading representative of a midspan flow. The characteristic Re of the LPT can vary by a factor of four between take-off and cruise conditions. In addition, the LPT operates at different Ma and the incident flow can have significant levels of turbulence due to upstream blade wakes. The paper investigates numerically using LES the flow around a LPT blading with three different Reynolds number Re = 175'000 (cruise), 280'000 (mid-level altitude) and 500'000 (take-off) keeping the same characteristic Mach number Ma = 0.2 and three different Mach number Ma = 0.2, 0.5 and 0.8 keeping the same Reynolds number Re= 280'000. These different simulations are performed with 0% Free Stream Turbulence (FST) followed by inlet turbulence (6% FST). The study focuses on different flow characteristics: pressure distribution around the blade, near-wall flow behavior, loss generation and Turbulent Kinetic Energy budget. The results show an earlier boundary layer separation on the aft of the blade suction side when the Re is increased while the free-stream turbulence delays separation. The TKE budget shows the predominant effect of the turbulent production and diffusion in the wake, the axial evolution of these different terms being relatively insensitive to Re and Ma.

Performance and Off-Design Characteristics for Low Pressure Turbine Outlet Guide Vanes: Measurements and Calculations

2006 ◽  
Author(s):  
Johan Hja¨rne ◽  
Jonas Larsson ◽  
Lennart Lo¨fdahl
Keyword(s):  
Numerical Simulations ◽  
Best Practice ◽  
Guide Vane ◽  
Turbulence Models ◽  
Low Pressure ◽  
Pressure Losses ◽  
Low Pressure Turbine ◽  
Best Practice Guidelines ◽  
Pressure Distributions ◽  
Design Characteristics

This paper presents 2D and 3D-numerical simulations compared with experimental data from a linear Low Pressure Turbine/Outlet Guide Vane (LPT/OGV) cascade at Chalmers in Sweden. Various performance characteristics for both on and off design cases were investigated, including; pressure distributions, total pressure losses and turning. The numerical simulations were performed with the goal to validate simulation methods and create best-practice guidelines for how to accurately and reliably predict performance and off-design characteristics for an LPT/OGV. The numerical part of the paper presents results using different turbulence models and levels of mesh refinement in order to assess what is the most appropriate simulation approach. From these results it can be concluded that the k-ε Realizable model predicts both losses and turning most accurately for both on and off design conditions.

An Experimental Investigation of Secondary Flows and Loss Development Downstream of a Highly Loaded Low Pressure Turbine Outlet Guide Vane Cascade

2006 ◽  
Author(s):  
Johan Hja¨rne ◽  
Valery Chernoray ◽  
Jonas Larsson ◽  
Lennart Lo¨fdahl
Keyword(s):  
Experimental Investigation ◽  
Guide Vane ◽  
Low Pressure ◽  
Secondary Flows ◽  
Flow Angle ◽  
Vortical Structures ◽  
Low Pressure Turbine ◽  
Passage Vortex ◽  
Flow Field Characteristics ◽  
Highly Loaded

This paper presents a detailed experimental investigation of the evolution of secondary flow field characteristics and losses at several measurement planes downstream of a highly loaded low pressure turbine/outlet guide vane (LPT/OGV). The experiments were carried out in a linear cascade at Chalmers in Sweden. Several realistic upstream incidences and turbulence intensities have been investigated for one Reynolds number. Downstream characteristics have been measured with a 5-hole pneumatic probe. This allows for the determination of the mean vortical structures, their development and their interactions. The passage vortex and the blade shed vorticity are clearly visible at different downstream positions. Their intensity is shown to be strongly dependent on the inlet flow angle. The turbulence level seems to play a role on both the mixing within, and between the structures. The measurements also show that the losses along the blade span are dependent on the development of these structures.

Numerical Validations of Secondary Flows and Loss Development Downstream of a Highly Loaded Low Pressure Turbine Outlet Guide Vane Cascade

2007 ◽  
Author(s):  
Johan Hja¨rne ◽  
Valery Chernoray ◽  
Jonas Larsson ◽  
Lennart Lo¨fdahl
Keyword(s):  
Numerical Simulations ◽  
Secondary Flow ◽  
Incompressible Flows ◽  
Guide Vane ◽  
Low Pressure ◽  
Flow Fields ◽  
Secondary Flows ◽  
Test Facility ◽  
Low Pressure Turbine ◽  
Highly Loaded

In this paper 3D numerical simulations of turbulent incompressible flows are validated against experimental data from the linear low pressure turbine/outlet guide vane (LPT/OGV) cascade at Chalmers in Sweden. The validation focuses on the secondary flow-fields and loss developments downstream of a highly loaded OGV. The numerical simulations are performed for the same inlet conditions as in the test-facility with engine-like properties in terms of Reynolds number, boundary-layer thickness and inlet flow angles with the goal to validate how accurately and reliably the secondary flow fields and losses for both on- and off-design conditions can be predicted for OGV’s. Results from three different turbulence models as implemented in FLUENT, k-ε Realizable, kω-SST and the RSM are validated against detailed measurements. From these results it can be concluded that the RSM model predicts both the secondary flow field and the losses most accurately.

A Correlation-Based Transition Model Using Local Variables—Part II: Test Cases and Industrial Applications

2004 ◽  
Vol 128 (3) ◽  
pp. 423-434 ◽  
Author(s):  
R. B. Langtry ◽  
F. R. Menter ◽  
S. R. Likki ◽  
Y. B. Suzen ◽  
P. G. Huang ◽  
...  
Keyword(s):  
Guide Vane ◽  
Current Model ◽  
Mathematical Formulation ◽  
Low Pressure ◽  
Transport Equations ◽  
Parallel Execution ◽  
Test Cases ◽  
Transition Model ◽  
Compressor Cascade ◽  
Low Pressure Turbine

A new correlation-based transition model has been developed, which is built strictly on local variables. As a result, the transition model is compatible with modern computational fluid dynamics (CFD) methods using unstructured grids and massive parallel execution. The model is based on two transport equations, one for the intermittency and one for the transition onset criteria in terms of momentum thickness Reynolds number. The proposed transport equations do not attempt to model the physics of the transition process (unlike, e.g., turbulence models), but form a framework for the implementation of correlation-based models into general-purpose CFD methods. Part I of this paper (Menter, F. R., Langtry, R. B., Likki, S. R., Suzen, Y. B., Huang, P. G., and Völker, S., 2006, ASME J. Turbomach., 128(3), pp. 413–422) gives a detailed description of the mathematical formulation of the model and some of the basic test cases used for model validation. Part II (this part) details a significant number of test cases that have been used to validate the transition model for turbomachinery and aerodynamic applications, including the drag crisis of a cylinder, separation-induced transition on a circular leading edge, and natural transition on a wind turbine airfoil. Turbomachinery test cases include a highly loaded compressor cascade, a low-pressure turbine blade, a transonic turbine guide vane, a 3D annular compressor cascade, and unsteady transition due to wake impingement. In addition, predictions are shown for an actual industrial application, namely, a GE low-pressure turbine vane. In all cases, good agreement with the experiments could be achieved and the authors believe that the current model is a significant step forward in engineering transition modeling.

On the Unsteady Formation of Secondary Flow Inside a Rotating Turbine Blade Passage

2013 ◽  
Vol 136 (6) ◽  
Author(s):  
C. M. Schneider ◽  
D. Schrack ◽  
M. Kuerner ◽  
M. G. Rose ◽  
S. Staudacher ◽  
...  
Keyword(s):  
Flow Field ◽  
Secondary Flow ◽  
Guide Vane ◽  
Low Pressure ◽  
Flow Structures ◽  
Low Pressure Turbine ◽  
Interaction Processes ◽  
Nozzle Guide Vane ◽  
Nozzle Guide ◽  
Secondary Flow Field

This paper addresses the unsteady formation of secondary flow structures inside a turbine rotor passage. The first stage of a two-stage, low-pressure turbine is investigated at a Reynolds Number of 75,000. The design represents the third and the fourth stages of an engine-representative, low-pressure turbine. The flow field inside the rotor passage is discussed in the relative frame of reference using the streamwise vorticity. A multistage unsteady Reynolds-averaged Navier–Stokes (URANS) prediction provides the time-resolved data set required. It is supported by steady and unsteady area traverse data acquired with five-hole probes and dual-film probes at rotor inlet and exit. The unsteady analysis reveals a nonclassical secondary flow field inside the rotor passage of this turbine. The secondary flow field is dominated by flow structures related to the upstream nozzle guide vane. The interaction processes at hub and casing appear to be mirror images and have characteristic forms in time and space. Distinct loss zones are identified, which are associated with vane-rotor interaction processes. The distribution of the measured isentropic stage efficiency at rotor exit is shown, which is reduced significantly by the secondary flow structures discussed. Their impacts on the steady as well as on the unsteady angle characteristics at rotor exit are presented to address the influences on the inlet conditions of the downstream nozzle guide vane. It is concluded that URANS should improve the optimization of rotor geometry and rotor loss can be controlled, to a degree, by nozzle guide vane (NGV) design.

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