A Geometry Parameterization Method for Three-Dimensional Aerodynamic Optimization

Author(s):  
Salim Koc ◽  
Hyoung Kim ◽  
Kazuhiro Nakahashi
Author(s):  
Philipp Amtsfeld ◽  
Michael Lockan ◽  
Dieter Bestle ◽  
Marcus Meyer

State-of-the-art aerodynamic blade design processes mainly consist of two phases: optimal design of 2D blade sections and then stacking them optimally along a three-dimensional stacking line. Such a quasi-3D approach, however, misses the potential of finding optimal blade designs especially in the presence of strong 3D flow effects. Therefore, in this paper a blade optimization process is demonstrated which uses an integral 3D blade model and 3D CFD analysis to account for three-dimensional flow features. Special emphasis is put on shortening design iterations and reducing design costs in order to obtain a rapid automatic optimization process for fully 3D aerodynamic turbine blade design which can be applied in an early design phase already. The three-dimensional parametric blade model is determined by up to 80 design variables. At first, the most important design parameters are chosen based on a non-linear sensitivity analysis. The objective of the subsequent optimization process is to maximize isentropic efficiency while fulfilling a minimal set of constraints. The CFD model contains both important geometric features like tip gaps and fillets, and cooling and leakage flows to sufficiently represent real flow conditions. Two acceleration strategies are used to cut down the turn-around time from weeks to days. Firstly, the aerodynamic multi-stage design evaluation is significantly accelerated with a GPU-based RANS solver running on a multi-GPU workstation. Secondly, a response surface method is used to reduce the number of expensive function evaluations during the optimization process. The feasibility is demonstrated by an application to a blade which is a part of a research rig similar to the high pressure turbine of a small civil jet engine. The proposed approach enables an automatic aerodynamic design of this 3D blade on a single workstation within few days.


2011 ◽  
Vol 287-290 ◽  
pp. 2801-2804 ◽  
Author(s):  
Liang Bo Ao ◽  
Yuan Sheng Li ◽  
Lei Li ◽  
Zhi Xun Wen ◽  
Zhu Feng Yue

The aerodynamic optimization for turbocharger turbine blade is studied using variable dimensionality analysis technology. The aerodynamic optimization procedure is decomposed to two steps: two-dimensional (2D) optimization and three-dimensional (3D) optimization based on the 2D optimal results. The quintic polynomial method with continuous three order derivatives is used to present section profile of three sections, root, middle and tip of blade. The 2D aerodynamic analysis and optimization are carried separately for different sections. Aerodynamic optimization for turbine blade is driven by the combination of global and local optimization arithmetic, with the 2D optimization blade as initial value, and profile parameter as design variable. The result shows that the calculation time is shortened and the optimization efficiency is improved, compared with the full 3D optimization under the same effect.


2021 ◽  
Author(s):  
D. Torre ◽  
G. García-Valdecasas ◽  
A. Puente ◽  
D. Hernández ◽  
S. Luque

Abstract The multi-stage intermediate pressure turbine (IPT) is a key enabler of the thermodynamic cycle in geared turbofan engine architectures, where fan and turbine rotational speeds become decoupled by employing a power gearbox between them. This allows for the separate aerodynamic optimization of both components, an increase in engine bypass ratios, higher propulsive efficiency, and lower specific fuel consumption. Due to significant aerodynamic differences with conventional low pressure turbines (LPTs), multi-stage IPT designs present new aerodynamic, mechanical and acoustic trade-offs. This work describes the aerodynamic design and experimental validation of a fully featured three-stage IP turbine, including a final row of outlet guide vanes. Experiments have been conducted in a highly engine-representative transonic rotating wind tunnel at the CTA (Centro de Tecnologías Aeronáuticas, Spain), in which Mach and Reynolds numbers were matched to engine conditions. The design intent is shown to be fully validated. Efficiency levels are discussed in the context of a previous state-of-the-art LPT, tested in the same facility. It is argued that the efficiency gains of IPTs are due to higher pitch-to-chord ratios, which lead to a reduction in overall profile losses, and higher velocity ratios and lower turning angles, which reduce airfoil secondary flows and three-dimensional losses.


Author(s):  
Guang Xi ◽  
Zhiheng Wang ◽  
Chunmei Zhang ◽  
Minjian Yuan

In this paper the design optimization of vaned diffuser for the 100kW microturbine’s centrifugal compressor is carried out. The forward-loaded and the conventional airfoil diffusers are respectively redesigned based on the surrogate model and the three dimensional viscous flow analyses. The objective of the optimization is to redesign the diffuser that assures, for a given operating condition of the centrifugal impeller, the stage isentropic efficiency to be highest. Using the surrogate model the optimization process is accelerated and the 3D flow analysis’s application to the practical engineering design is efficiently realized. To validate the optimization result, the compressor stage performance test is performed on a high speed centrifugal compressor test rig with one original diffuser and its redesigned, respectively.


Author(s):  
Jiandao Yang ◽  
Taowen Chen ◽  
Jun Li ◽  
Zhenping Feng

Combined with three-dimensional parameterization method of exhaust diffuser profile, aerodynamic performance evaluation method, response surface approximation evaluation model and Hooke-Jeeves direct search approach, aerodynamic optimization design of exhaust hood diffuser for steam turbine is presented. The aerodynamic performance of exhaust hood design candidate is evaluated using three-dimensional Reynolds-Averaged Navier-Stokes (RANS) solutions. Aerodynamic optimization design of exhaust hood is conducted for the maximum of the static pressure recovery coefficient of exhaust hood. The design variables are specified by the exhaust diffuser profile parameterization method. The aerodynamic performance of the optimized exhaust hood and referenced design is numerically calibrated with consideration of the full last stage and rotor tip clearance. The static pressure recovery coefficient of the optimized exhaust hood is higher than that of the referenced design with consideration of the upstream last stage influence. Furthermore, the detailed flow pattern of the optimized exhaust hood and referenced design is also analyzed and compared.


2008 ◽  
Vol 4 (4) ◽  
pp. 385-392 ◽  
Author(s):  
GAO Hangshan ◽  
HAN Yongzhi ◽  
ZHANG Juan ◽  
YUE Zhufeng

Based on aerodynamic analysis, an optimization method for the profiles of turbine blade is studied in this paper. This method is capable of addressing multiple objectives and constrains without relying on user input. A quintic polynomial is used to build the three‐dimensional blade model and a three dimensional Navier‐Stokes solver was used to solve the flow field around the turbine blade. The objective functions are the turbine aerodynamic efficiency and total pressure ratio. The optimization is completed with the K‐S function technique and accelerated by approximation technique. Finally, the proposed method is applied to optimizing a true blade to validate its accuracy and efficiency. The obtained result shows that the approximation method is more efficient and accurate than the conventional method.


Author(s):  
Liu He ◽  
Peng Shan

Integrating a genetic algorithm code with a response surface methodology code based upon the artificial neural network model, this paper develops an optimization system. By introducing a quasi-three dimensional through-flow design code and a design code of axial compressor airfoils with camber lines of arbitrary shape, and involving a three-dimensional computational fluid dynamics solver, this paper establishes a numerical aerodynamic optimization platform for the three-dimensional blades of axial compressors. The optimization in this paper mainly has four features. First, it applies the conventional inverse design method instead of the common computer aided design parameterization method to generate a three-dimensional blade. Second, it chooses aerodynamic parameters with physical meaning as optimization design variables instead of purely geometrical parameters. Third, it presents a stage-by-stage optimization strategy about the multistage turbomachinery optimization. Fourth, it introduces the visual sensitivity analysis method into optimization, which can adjust variation ranges of variables by analysing how great the variables influence the objective function. The above techniques were applied to the redesign of a single rotor row and two double-stage axial fans separately. The departure angles and work distributions in the inverse design were taken as design variables separately in optimizations of the single rotor and double-stage fans, and they were parametrically represented by means of Be´zier curves, whose parameters were used as the optimization variables in the practical operation. The three investigated examples elucidate that not only the techniques mentioned above are appropriate and effective in engineering, but also the design guidance for similar inverse design problems can be obtained from the optimization results.


2012 ◽  
Vol 271-272 ◽  
pp. 1039-1043
Author(s):  
Gao Su ◽  
G.Y. Zhou ◽  
Fei Du

To the unsteady characteristic of three-dimensional flow in the gas turbine blade cascades, based on sliding mesh and a standard turbulent flow model, Fluent software was employed to solve the Reynolds averaged N-S equation. The numberical result of unsteady flow field is obtained in gas turbine cascade for supercharged marine boiler. This paper shows the axial distribution of Ma in the position of β=0 in a calculational period time, and the effect of trails to flow field characteristics. The result can provide guidelines for aerodynamic optimization design of gas turbine stage cascade.


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