Aerodynamic optimization design of low aspect ratio transonic turbine stage

2006 ◽  
Vol 19 (04) ◽  
pp. 500 ◽  
Author(s):  
Liming SONG
Keyword(s):  
Aspect Ratio ◽  
Optimization Design ◽  
Turbine Stage ◽  
Aerodynamic Optimization ◽  
Low Aspect Ratio ◽  
Transonic Turbine

The Effect of a Downstream Rotor on the Measured Performance of a Transonic Turbine Nozzle

1986 ◽  
Vol 108 (2) ◽  
pp. 269-274
Author(s):  
R. G. Williamson ◽  
S. H. Moustapha ◽  
J. P. Huot
Keyword(s):  
Performance Evaluation ◽  
Aspect Ratio ◽  
Flow Field ◽  
Large Scale ◽  
Outer Wall ◽  
Nozzle Flow ◽  
Turning Angle ◽  
Low Aspect Ratio ◽  
Transonic Turbine ◽  
Mach Numbers

Two nozzle designs, involving the same low aspect ratio, high turning angle vanes, and differing in outer wall contour, were tested over a range of exit Mach numbers up to supersonic values. The experiments were conducted on a large-scale, full annular configuration with and without a representative rotor downstream. Nozzle performance was found to be significantly affected by rotor operation, the influence depending on the detailed characteristics of the nozzle flow field, as well as on the design and operation of the rotor itself. It is suggested that performance evaluation of low aspect ratio nozzles of high turning angle may require appropriate testing with a rotor.

Unsteady Aerodynamics of a Low Aspect Ratio Turbine Stage: Modeling Issues and Flow Physics

2012 ◽  
Vol 134 (6) ◽  
Author(s):  
G. Persico ◽  
A. Mora ◽  
P. Gaetani ◽  
M. Savini
Keyword(s):  
Aspect Ratio ◽  
Coming Out ◽  
Three Dimensional ◽  
Unsteady Aerodynamics ◽  
Fast Response ◽  
Operating Conditions ◽  
Pressure Probe ◽  
Turbine Stage ◽  
Time Resolved ◽  
Low Aspect Ratio

In this paper the three-dimensional unsteady aerodynamics of a low aspect ratio, high pressure turbine stage are studied. In particular, the results of fully unsteady three-dimensional numerical simulations, performed with ANSYS-CFX, are critically evaluated against experimental data. Measurements were carried out with a novel three-dimensional fast-response pressure probe in the closed-loop test rig of the Laboratorio di Fluidodinamica delle Macchine of the Politecnico di Milano. An analysis is first reported about the strategy to limit the CPU and memory requirements while performing three-dimensional simulations of blade row interaction when the rotor and stator blade numbers are prime to each other. What emerges as the best choice is to simulate the unsteady behavior of the rotor alone by applying the stator outlet flow field as a rotating inlet boundary condition (scaled on the rotor blade pitch). Thanks to the reliability of the numerical model, a detailed analysis of the physical mechanisms acting inside the rotor channel is performed. Two operating conditions at different vane incidence are considered, in a configuration where the effects of the vortex-blade interaction are highlighted. Different vane incidence angles lead to different size, position, and strength of secondary vortices coming out from the stator, thus promoting different interaction processes in the subsequent rotor channel. However some general trends can be recognized in the vortex-blade interaction: the sense of rotation and the spanwise position of the incoming vortices play a crucial role on the dynamics of the rotor vortices, determining both the time-mean and the time-resolved characteristics of the secondary field at the exit of the stage.

Adjoint-Based Unsteady Aerodynamic Optimization of a Transonic Turbine Stage

2016 ◽  
Author(s):  
Can Ma ◽  
Xinrong Su ◽  
Xin Yuan
Keyword(s):  
Unsteady Flow ◽  
Stokes Equations ◽  
Harmonic Balance Method ◽  
Adjoint Equations ◽  
Turbine Stage ◽  
Aerodynamic Optimization ◽  
Optimization System ◽  
Unsteady Aerodynamic ◽  
Blade Row ◽  
Transonic Turbine

Unsteady blade row interactions considerably affect the performance of turbomachinery consisting of multiple blade rows. However, most aerodynamic optimizations of turbomachinery are based on mixing-plane steady flow simulations which cannot account for the unsteady effects of blade row interactions. In this work, the rotor of a two-dimensional transonic turbine stage is optimized using an in-house unsteady aerodynamic optimization system that allows for a more accurate modeling of the unsteady flow features occurring in multi-row turbomachinery configurations. The gradients of the objective function and constraint to the design variables are efficiently calculated with the discrete adjoint method. In the developed adjoint-based unsteady aerodynamic optimization system, the unsteady Reynolds-Averaged Navier-Stokes equations are solved using the harmonic balance method with an in-house code. The adjoint equations are derived by hand from the discrete form of the unsteady flow equations. The present results demonstrate the efficiency and capability of the unsteady aerodynamic optimization system for turbomachinery with multiple blade rows.

Steady CFD Analysis on Gas Turbine Stage Cascade Based on Mixing Plane Model

2012 ◽  
Vol 184-185 ◽  
pp. 473-476 ◽  
Author(s):  
Gao Su ◽  
Guo Yi Zhou ◽  
Fei Du
Keyword(s):  
Gas Turbine ◽  
Optimization Design ◽  
Flow Model ◽  
Scientific Management ◽  
Turbine Cascade ◽  
Wall Function ◽  
Turbine Stage ◽  
Aerodynamic Optimization ◽  
Plane Model ◽  
Explicit Solver

Based on a standard dual-equation turbulent flow model and coupled explicit solver,a wall function method was employed to closure the Reynolds averaged N-S equation .The mixing plane method was adopted to tranfer parameters between rotor and stator cascades. A approximate linear law is obtained in gas turbine cascade for supercharged marine boiler,which governs the variation of some parameters at the outlet of the turbine stage cascade along the blade height direction,such as pressure,velocity,as well as temperature and Ma.The results can provide guidelines for aerodynamic optimization design of the gas turbine stage cascade and the scientific management of this kind of set.

Unsteady Aerodynamics of a Low Aspect Ratio Turbine Stage: Modeling Issues and Flow Physics

2010 ◽  
Author(s):  
G. Persico ◽  
A. Mora ◽  
P. Gaetani ◽  
M. Savini
Keyword(s):  
Aspect Ratio ◽  
Coming Out ◽  
Cfd Simulation ◽  
Three Dimensional ◽  
Unsteady Aerodynamics ◽  
Fast Response ◽  
Pressure Probe ◽  
Turbine Stage ◽  
Aerodynamic Pressure ◽  
Low Aspect Ratio

In this paper the three-dimensional unsteady aerodynamics of a low aspect ratio, high pressure turbine stage is studied. Fully unsteady, three-dimensional numerical simulations are performed using the commercial code ANSYS-CFX The numerical model is critically evaluated against experimental data. Measurements were performed with a three-dimensional fast-response aerodynamic pressure probe in the closed-loop test rig operating in the Laboratorio di Fluidodinamica delle Macchine of the Politecnico di Milano (Italy). An analysis is first reported about the strategy to reduce the CPU and memory requirements while performing three-dimensional simulations of stator-rotor interaction in actual turbomachinery. What emerges as the best choice, at least for subsonic stages, is to simulate the unsteady behaviour of the rotor blade row alone by applying the stator outlet flow field as rotating inlet boundary condition. When measurements are available upstream of the rotor the best representation of the experimental results downstream of the stage is achieved. The agreement with the experiments achieved at the rotor exit makes the CFD simulation a key-tool for the comprehension and the interpretation of the physical mechanisms acting inside the rotor channel (often difficult to achieve using experiments only). Numerical investigations have been carried out by varying the incidence at the vane entrance. Different vane incidence angles lead to different size, position, and strength of secondary vortices coming out from the stator. The configuration is chosen is such a way to isolate the effects of the vortex-blade interaction. Results show that some general trends can be recognized in the vortex-blade interaction. The sense of rotation and the spanwise position of the incoming vortices play a crucial role on their interaction with the rotor vortices, thus determining both the time-mean and the time-resolved characteristics of the stage-exit secondary field.

An Application of 3-D Viscous Flow Analysis to the Design of a Low-Aspect-Ratio Turbine

1979 ◽  
Author(s):  
H. C. Liu ◽  
T. C. Booth ◽  
W. A. Tall
Keyword(s):  
Aspect Ratio ◽  
Viscous Flow ◽  
Flow Analysis ◽  
Optimization Procedure ◽  
Tip Clearance ◽  
Specific Work ◽  
Turbine Stage ◽  
Gas Generator ◽  
Low Aspect Ratio

Previously reported cascade test results verified and provided a calibration of the 3-D viscous flow analysis. This paper describes the subsequent AFAPL-sponsored technology program in which the 3-D viscous flow computer program was used to optimize the low-aspect-ratio stator of a high-work turbine stage. The optimization procedure, in conjunction with the radial distribution of energy extraction, led to innovative-but-realistic blading for advanced gas generator turbines. A turbine stage was tested with this stator, in conjunction with an appropriate rotor design. The total-to-total design-point efficiency — 92 percent at 1-percent tip clearance — was achieved at 31.83 Btu/lbm specific work. In addition to stage tests, separate stator tests were conducted including a measurement of total pressure loss and stator reaction torque, which provided baseline data to assess interaction effects during stage testing with stator reaction measurements “in vivo.”

Unsteady Analysis of Inter-Rows Stator-Rotor Spacing Effects on a Transonic, Low-Aspect Ratio Turbine

2015 ◽  
Author(s):  
Etienne Tang ◽  
Gilles Leroy ◽  
Mickaël Philit ◽  
Jacques Demolis
Keyword(s):  
Experimental Data ◽  
Aspect Ratio ◽  
High Pressure Turbine ◽  
Low Aspect Ratio ◽  
Spacing Effects ◽  
Air Turbine ◽  
Flow Features ◽  
Aerodynamic Performances ◽  
Flow Through ◽  
Transonic Turbine

The aerodynamic performances of an axial turbine are affected by the distance between the stator and the rotor. Previous studies have shown different trends, depending mainly on whether the turbine is subsonic or not. The present paper aims at improving the understanding of the effect of rows spacing on the flow through a transonic turbine. A one-stage, low aspect ratio, high pressure turbine case is investigated using CFD. Steady and unsteady phase-lagged RANS computations are performed on this configuration with different inter-blade rows distances. The results are successfully compared with experimental data from a cold air turbine rig. Entropy production balances are used to emphasize the main loss areas and the loss variations caused by changes in inter-blade rows distance. Two techniques are compared for computing these balances, and one of them appears to perform much better. The flow features causing these losses are then identified. Finally, an optimal inter-rows spacing is found. It is a compromise between the losses created by strong stator-rotor interactions at small inter-rows gaps and the losses generated at the endwalls in the inter-rows space at large distances.

Effect of End Wall Contouring on Performance of Ultra-Low Aspect Ratio Transonic Turbine Inlet Guide Vanes

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Toyotaka Sonoda ◽  
Martina Hasenjäger ◽  
Toshiyuki Arima ◽  
Bernhard Sendhoff
Keyword(s):  
Aspect Ratio ◽  
Secondary Flow ◽  
Three Dimensional ◽  
Design Concept ◽  
Guide Vanes ◽  
Low Aspect Ratio ◽  
Inlet Guide Vanes ◽  
Turbine Inlet ◽  
Transonic Turbine ◽  
End Wall

In our previous work on ultralow-aspect ratio transonic turbine inlet guide vanes (IGVs) for a small turbofan engine (Hasenjäger et al., 2005, “Three Dimensional Aerodynamic Optimization for an Ultra-Low Aspect Ratio Transonic Turbine Stator Blade,” ASME Paper No. GT2005-68680), we used numerical stochastic design optimization to propose the new design concept of an extremely aft-loaded airfoil to improve the difficult-to-control aerodynamic loss. At the same time, it is well known that end wall contouring is an effective method for reducing the secondary flow loss. In the literature, both “axisymmetric” and “nonaxisymmetric” end wall geometries have been suggested. Almost all of these geometric variations have been based on the expertise of the turbine designer. In our current work, we employed a stochastic optimization method—the evolution strategy—to optimize and analyze the effect of the axisymmetric end wall contouring on the IGV’s performance. In the optimization, the design of the end wall contour was divided into three different approaches: (1) only hub contour, (2) only tip contour, and (3) hub and tip contour, together with the possibility to observe the correlation between hub/tip changes with regard to their joint influence on the pressure loss. Furthermore, three-dimensional flow mechanisms, related to a secondary flow near the end wall region in the low-aspect ratio transonic turbine IGV, was investigated, based on the above optimization results. A design concept and secondary flow characteristics for the low-aspect ratio full annular transonic turbine IGV is discussed in this paper.

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