A Study of Advanced High-Loaded Transonic Turbine Airfoils

2004 ◽  
Vol 128 (4) ◽  
pp. 650-657 ◽  
Author(s):  
Toyotaka Sonoda ◽  
Toshiyuki Arima ◽  
Markus Olhofer ◽  
Bernhard Sendhoff ◽  
Friedrich Kost ◽  
...  

The development of high-performance turbine airfoils has been investigated under the condition of a supersonic exit Mach number. In order to obtain a new aerodynamic design concept for a high-loaded turbine rotor blade, we employed an evolutionary algorithm for numerical optimization. The target of the optimization method, which is called evolutionary strategy (ES), was the minimization of the total pressure loss and the deviation angle. The optimization process includes the representation of the airfoil geometry, the generation of the grid for a blade-to-blade computational fluid dynamics analysis, and a two-dimensional Navier-Stokes solver with a low-Re k-ε turbulence model in order to evaluate the performance. Some interesting aspects, for example, a double shock system, an early transition, and a redistribution of aerodynamic loading on blade surface, observed in the optimized airfoil, are discussed. The increased performance of the optimized blade has been confirmed by detailed experimental investigation, using conventional probes, hotfilms, and L2F system.

Author(s):  
Toyotaka Sonoda ◽  
Toshiyuki Arima ◽  
Markus Olhofer ◽  
Bernhard Sendhoff ◽  
Friedrich T. Kost ◽  
...  

The development of high performance turbine airfoils has been investigated under the condition of a supersonic exit Mach number. In order to obtain a new aerodynamic design concept for a high loaded turbine rotor blade, we employed an evolutionary algorithm for numerical optimization. The target of the optimization method, which is called evolution strategy (ES), was the minimization of the total pressure loss and the deviation angle. The optimization process includes the representation of the airfoil geometry, the generation of the grid for a blade-to-blade CFD analysis, and a 2D Navier-Stokes solver with a low-Re k-ε turbulence model in order to evaluate the performance. Some interesting aspects, for example, a double shock system, an early transition and a re-distribution of aerodynamic loading on blade surface, observed in the optimized airfoil, are discussed. The increased performance of the optimized blade has been confirmed by detailed experimental investigation, using conventional probes, hot-films and L2F system.


Author(s):  
Lifang Zeng ◽  
Dingyi Pan ◽  
Shangjun Ye ◽  
Xueming Shao

A fast multiobjective optimization method for S-duct scoop inlets considering both inflow and outflow is developed and validated. To reduce computation consumption of optimization, a simplified efficient model is proposed, in which only inflow region is simulated. Inlet pressure boundary condition of the efficient model is specified by solving an integral model with both inflow and outflow. An automated optimization system integrating the computational fluid dynamics analysis, nonuniform rational B-spline geometric representation technique, and nondominated sorting genetic algorithm II is developed to minimize the total pressure loss and distortion at the exit of diffuser. Flow field is numerically simulated by solving the Reynolds-averaged Navier–Stokes equation coupled with k–ω shear stress transport turbulence model, and results are validated to agree well with previous experiment. S-duct centreline shape and cross-sectional area distribution are parameterized as the design variables. By analyzing the results of a suggested optimal inlet chosen from the obtained Pareto front, total pressure recovery has increased from 97% to 97.4%, and total pressure distortion DC60 has decreased by 0.0477 (21.7% of the origin) at designed Mach number 0.7. The simplified efficient model has been validated to be reliable, and by which the time cost for the optimization project has been reduced by 70%.


2020 ◽  
Vol 142 (10) ◽  
Author(s):  
Wen Yao Lee ◽  
William N. Dawes ◽  
John D. Coull

Abstract Casting deviations introduce geometric variability that impacts the aerodynamic performance of turbomachinery. These effects are studied for a high-pressure turbine rotor blade from a modern aero-engine. A sample of 197 blades were measured using structured-light three-dimensional scanning, and the performance of each blade is quantified using Reynolds-averaged Navier–Stokes (RANS) simulations. Casting variation is typically managed by applying geometric tolerances to determine the suitability of a component for service. The analysis demonstrates that this approach may not be optimal since it does not necessarily align with performance, in particular the capacity and efficiency. Alternatively, functional acceptance based on the predicted performance of each blade removes the uncertainty associated with geometric tolerancing and gives better performance control. Building on these findings, the paper proposes a method to set the orientation of the fir-tree, which is machined after casting. By customizing the alignment of each blade, performance variability and scrap rates can be significantly reduced. The method uses predictions of performance to reorient the castings to compensate for manufacturing-induced errors, without changing the design-intent blade geometry and with minimal changes to the manufacturing facility.


Author(s):  
Thomas Coton ◽  
Tony Arts ◽  
Michae¨l Lefebvre ◽  
Nicolas Liamis

An experimental and numerical study was performed about the influence of incoming wakes and the calming effect on a very high lift low pressure turbine rotor blade. The first part of the paper describes the experimental determination of the pressure loss coefficient and the heat transfer around the blade mounted in a high speed linear cascade. The cascade is exposed to incoming wakes generated by high speed rotating bars. Their aim is to act upon the transition/separation phenomena. The measurements were conducted at a constant exit Mach number equal to 0.8 and at three Reynolds number values, namely 190000, 350000 and 650000. The inlet turbulence level was fixed at 0.8%. An additional feature of this work is to identify the boundary layer status through heat transfer measurements. Compared to the traditionally used hot films, thin film heat flux gages provide fully quantitative data required for code validation. Numerical computations are presented in the second part of the paper.


Author(s):  
R. Heider ◽  
J. M. Duboue ◽  
B. Petot ◽  
G. Billonnet ◽  
V. Couaillier ◽  
...  

A 3D Navier-Stokes investigation of a high pressure turbine rotor blade including tip clearance effects is presented. The 3D Navier-Stokes code developed at ONERA solves the three-dimensional unsteady set of mass-averaged Navier-Stokes equations by the finite volume technique. A one step Lax-Wendroff type scheme is used in a rotating frame of reference. An implicit residual smoothing technique has been implemented, which accelerates the convergence towards the steady state. A mixing length model adapted to 3D configurations is used. The turbine rotor flow is calculated at transonic operating conditions. The tip clearance effect is taken into account. The gap region is discretized using more than 55,000 points within a multi-domain approach. The solution accounts for the relative motion of the blade and casing surfaces. The total mesh is composed of five sub-domains and counts 710,000 discretization points. The effect of the tip clearance on the main flow is demonstrated. The calculation results are compared to a 3D inviscid calculation, without tip clearance.


Author(s):  
A. A. Ameri ◽  
E. Steinthorsson

Predictions of the rate of heat transfer to the tip and shroud of a gas turbine rotor blade are presented. The simulations are performed with a multiblock computer code which solves the Reynolds Averaged Navier-Stokes equations. The effect of inlet boundary layer thickness as well as rotation rate on the tip and shroud heat transfer is examined. The predictions of the blade tip and shroud heat transfer are in reasonable agreement with the experimental measurements. Areas of large heat transfer rates are identified and physical reasoning for the phenomena presented.


1999 ◽  
Vol 122 (2) ◽  
pp. 278-285 ◽  
Author(s):  
Neil W. Harvey ◽  
Martin G. Rose ◽  
Mark D. Taylor ◽  
Shahrokh Shahpar ◽  
Jonathan Hartland ◽  
...  

A linear design system, already in use for the forward and inverse design of three-dimensional turbine aerofoils, has been extended for the design of their end walls. This paper shows how this method has been applied to the design of a nonaxisymmetric end wall for a turbine rotor blade in linear cascade. The calculations show that nonaxisymmetric end wall profiling is a powerful tool for reducing secondary flows, in particular the secondary kinetic energy and exit angle deviations. Simple end wall profiling is shown to be at least as beneficial aerodynamically as the now standard techniques of differentially skewing aerofoil sections up the span, and (compound) leaning of the aerofoil. A design is presented that combines a number of end wall features aimed at reducing secondary loss and flow deviation. The experimental study of this geometry, aimed at validating the design method, is the subject of the second part of this paper. The effects of end wall perturbations on the flow field are calculated using a three-dimensional pressure correction based Reynolds-averaged Navier–Stokes CFD code. These calculations are normally performed overnight on a cluster of work stations. The design system then calculates the relationships between perturbations in the end wall and resulting changes in the flow field. With these available, linear superposition theory is used to enable the designer to investigate quickly the effect on the flow field of many combinations of end wall shapes (a matter of minutes for each shape). [S0889-504X(00)00902-8]


1996 ◽  
Vol 118 (2) ◽  
pp. 307-313 ◽  
Author(s):  
A. A. Ameri ◽  
A. Arnone

The effect of transition modeling on the heat transfer predictions from rotating turbine blades was investigated. Three-dimensional computations using a Reynolds-averaged Navier–Stokes code were performed. The code utilized the Baldwin–Lomax algebraic turbulence model, which was supplemented with a simple algebraic model for transition. The heat transfer results obtained on the blade surface and the hub endwall were compared with experimental data for two Reynolds numbers and their corresponding rotational speeds. The prediction of heat transfer on the blade surfaces was found to improve with the inclusion of the transition length model and wake-induced transition effects over the simple abrupt transition model.


1984 ◽  
Vol 106 (2) ◽  
pp. 414-420 ◽  
Author(s):  
J.-J. Camus ◽  
J. D. Denton ◽  
J. V. Soulis ◽  
C. T. J. Scrivener

Detailed experimental measurements of the flow in a cascade of turbine rotor blades with a nonplanar end wall are reported. The cascade geometry was chosen to model as closely as possible that of a H.P. gas turbine rotor blade. The blade section is designed for supersonic flow with an exit Mach number of 1.15 and the experiments covered a range of exit Mach numbers from 0.7–1.2. Significant three-dimensional effects were observed and the origin of these is discussed. The measurements are compared with data for the same blade section in a two-dimensional cascade and also with the predictions of two different fully three-dimensional inviscid flow calculation methods. It is found that both these calculations predict the major three-dimensional effects on the flow correctly.


2003 ◽  
Vol 125 (2) ◽  
pp. 281-290 ◽  
Author(s):  
Thomas Coton ◽  
Tony Arts ◽  
Michae¨l Lefebvre ◽  
Nicolas Liamis

An experimental and numerical study was performed about the influence of incoming wakes and the calming effect on a very high-lift low-pressure turbine rotor blade. The first part of the paper describes the experimental determination of the pressure loss coefficient and the heat transfer around the blade mounted in a high-speed linear cascade. The cascade is exposed to incoming wakes generated by high-speed rotating bars. Their aim is to act upon the transition/separation phenomena. The measurements were conducted at a constant exit Mach number equal to 0.8 and at three Reynolds number values; namely, 190,000, 350,000, and 650,000. The inlet turbulence level was fixed at 0.8%. An additional feature of this work is to identify the boundary layer status through heat transfer measurements. Compared to the traditionally used hot films, thin film heat flux gages provide fully quantitative data required for code validation. Numerical computations are presented in the second part of the paper.


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