Study of Blade Sweep Effects of Compressor

Author(s):  
C. Xu ◽  
R. S. Amano

The three dimensional blading had been used for years in the process of turbomachine designs. In need of turbine blade designs in an efficient manner, the current advancement of CFD technologies allows effective 3D predictions of a complex 3D flow field in turbine blade passages, which can improve the turbine blade performances. Since numerous advantages of 3-D CFD usage had been reported in the open literature, many industries already started to use 3D blading in their turbomachines. In addition, a blade lean and a sweep for the blade design had been also implemented to increase the blade row efficiency. Experimental studies have shown some advantages of these lean and sweep features. Most of the experimental results combine many other features together. However, it is difficult to determine what the effects of different features should be. In this study, detailed numerical analyses were developed and these were used to present the results to gain better understanding of different feature of 3D blading for turbine designers and engineers. Throughout this paper performance impacts on different 3D features are presented and the superiority of the present approach is discussed.

Author(s):  
S M Fraser ◽  
A M Abdel-Razek ◽  
M Z Abdullah

Three-dimensional turbulent flow in a model cyclone has been simulated using PHOENICS code and experimental studies carried out using a laser Doppler anemometry (LDA) system. The experimental results were used to validate the computed velocity distributions based on the standard and a modified k-∊ model. The standard k-∊ model was found to be unsatisfactory for the prediction of the flow field inside the cyclone chamber. By considering the strong swirling flow and the streamlined curvature, a k-∊ model, modified to take account of the Richardson number, provided better velocity distributions and better agreement with the experimental results.


Author(s):  
Martin Lipfert ◽  
Jan Habermann ◽  
Martin G. Rose ◽  
Stephan Staudacher ◽  
Yavuz Guendogdu

In a joint project between the Institute of Aircraft Propulsion Systems (ILA) and MTU Aero Engines a two-stage low pressure turbine is tested at design and strong off-design conditions. The experimental data taken in the altitude test-facility aims to study the effect of positive and negative incidence of the second stator vane. A detailed insight and understanding of the blade row interactions at these regimes is sought. Steady and time-resolved pressure measurements on the airfoil as well as inlet and outlet hot-film traverses at identical Reynolds number are performed for the midspan streamline. The results are compared with unsteady multi-stage CFD predictions. Simulations agree well with the experimental data and allow detailed insights in the time-resolved flow-field. Airfoil pressure field responses are found to increase with positve incidence whereas at negative incidence the magnitude remains unchanged. Different pressure to suction side phasing is observed for the studied regimes. The assessment of unsteady blade forces reveals that changes in unsteady lift are minor compared to changes in axial force components. These increase with increasing positive incidence. The wake-interactions are predominating the blade responses in all regimes. For the positive incidence conditions vane 1 passage vortex fluid is involved in the midspan passage interaction leading to a more distorted three-dimensional flow field.


Author(s):  
D. B. M. Jouini ◽  
S. A. Sjolander ◽  
S. H. Moustapha

The paper presents detailed mid-span experimental results from two transonic linear turbine cascades. The blades for the two cascades were designed for the same service and differ mainly in their leading-edge geometries. One of the goals of the study was investigate the influence of the leading-edge metal angle on the sensitivity of the blade to positive off-design incidence. Measurements were made for incidence values of −10.0°, 0.0°, +4.5°, +10.0°, and +14.5° relative to design incidence. The exit Mach numbers varied roughly from 0.5 to 1.2 and the Reynolds numbers from about 4×105 to 106. The measurements include the midspan losses, blade loadings and base pressures. In addition, the axial-velocity-density ratio (AVDR) was extracted for each operating point The AVDR was found to vary from about 0.98 at −10.0° of incidence to about 1.27 at +14.5°. Thus, the data set also provides some evidence of the influence AVDR on axial turbine blade performance. Detailed experimental results for turbine blade performance at off-design incidence are very scarce in the open literature, particularly for transonic conditions. Among other things, the present results are intended to expand the database available in the open literature. To this end, the key aerodynamic results are presented in tabular form, along with the detailed geometry of the cascades. The results could be used in the development of new or improved correlations for use in the early stages of design. They could also be used to evaluate the ability of current CFD codes to capture reliably the variation in losses and other aerodynamic quantities with variations in blade incidence.


2018 ◽  
Vol 41 (4) ◽  
pp. 990-1001
Author(s):  
Song Ma ◽  
Jianguo Tan ◽  
Xiankai Li ◽  
Jiang Hao

This paper establishes a novel mathematical model for computing the plume flow field of a carrier-based aircraft engine. Its objective is to study the impact of jet exhaust gases with high temperature, high speed and high pressure on the jet blast deflector. The working condition of the nozzle of a fully powered on engine is first determined. The flow field of the exhaust jet is then numerically simulated at different deflection angle using the three-dimensional Reynolds averaged Navier–Stokes equations and the standard [Formula: see text]-[Formula: see text] turbulence method. Moreover, infra-red temperature tests are further carried out to test the temperature field when the jet blast deflector is at the [Formula: see text] deflection angle. The comparison between the simulation results and the experimental results show that the proposed computation model can perfectly describe the system. There is only 8–10% variation between them. A good verification is achieved. Moreover, the experimental results show that the jet blast deflector plays an outstanding role in driving the high-temperature exhaust gases. It is found that [Formula: see text] may be the best deflection angle to protect the deck and the surrounding equipment effectively. These data results provide a valuable basis for the design and layout optimization of the jet blast deflector and deck.


Author(s):  
Yuki Kajikawa ◽  
Masamitsu Kuroiwa ◽  
Naohiro Otani

In this paper, a three-dimensional (3D) tsunami flow model was proposed in order to predict a 3D flow field around a harbor accurately when tsunami strikes. In the proposed numerical model, the Cartesian coordinate system was adopted, and the Fractional Area/Volume Obstacle Representation (FAVOR) method, which has the ability to impose boundary conditions smoothly at complex boundaries, was introduced into the governing equations in consideration of applying the estimation to actual harbors with complex shape in the future. Moreover, the fifth-order Weighted Essentially Non- Oscillatory (WENO) scheme, which is a technique for achieving high accuracy even if the calculation mesh is coarse, was applied to discretization of the convection terms of the governing equations. In order to verify the validity of the model, it was applied to a large-scale laboratory experiment with a scale model of harbor. Comparisons between the simulated and experimental results showed that the model was able to reproduce the time variation of the flow field with sufficient accuracy. Moreover, the simulated results showed that a complex 3D flow field with some vertical vortex flows was generated around a harbor when tsunami struck.


Author(s):  
J. D. Denton ◽  
L Xu

Many of the phenomena involved in turbomachinery flow can be understood and predicted on a two-dimensional (2D) or quasi-three-dimensional (Q3D) basis, but some aspects of the flow must be considered as fully three-dimensional (3D) and cannot be understood or predicted by the Q3D approach. Probably the best known of these fully 3D effects is secondary flow, which can only be predicted by a fully 3D calculation which includes the vorticity at inlet to the blade row. It has long been recognized that blade sweep and lean also produce fully 3D effects and approximate methods of calculating these have been developed. However, the advent of fully 3D flow field calculation methods has made predictions of these complex effects much more readily available and accurate so that they are now being exploited in design. This paper will attempt to describe and discuss fully 3D flow effects with particular reference to their use to improve turbomachine performance. Although the discussion is restricted to axial flow machines, many of the phenomena discussed are equally applicable to mixed and radial flow turbines and compressors.


2014 ◽  
Vol 136 (11) ◽  
Author(s):  
Martin Lipfert ◽  
Jan Habermann ◽  
Martin G. Rose ◽  
Stephan Staudacher ◽  
Yavuz Guendogdu

In a joint project between the Institute of Aircraft Propulsion Systems (ILA) and MTU Aero Engines, a two-stage low pressure turbine is tested at design and strong off-design conditions. The experimental data taken in the Altitude Test Facility (ATF) aims to study the effect of positive and negative incidence of the second stator vane. A detailed insight and understanding of the blade row interactions at these regimes is sought. Steady and time-resolved pressure measurements on the airfoil as well as inlet and outlet hot-film traverses at identical Reynolds number are performed for the midspan streamline. The results are compared with unsteady multistage computational fluid dynamics (CFD) predictions. Simulations agree well with the experimental data and allow detailed insights in the time-resolved flow-field. Airfoil pressure field responses are found to increase with positive incidence whereas at negative incidence the magnitude remains unchanged. Different pressure to suction side (SS) phasing is observed for the studied regimes. The assessment of unsteady blade forces reveals that changes in unsteady lift are minor compared to changes in axial force components. These increase with increasing positive incidence. The wake-interactions are predominating the blade responses in all regimes. For the positive incidence conditions, vane 1 passage vortex fluid is involved in the midspan passage interaction, leading to a more distorted three-dimensional (3D) flow field.


1985 ◽  
Vol 107 (2) ◽  
pp. 301-307 ◽  
Author(s):  
I. K. Jennions ◽  
P. Stow

The purpose of this work has been to develop a quasi-three-dimensional blade design and analysis system incorporating fully linked throughflow, blade-to-blade and blade section stacking programs. In Part I of the paper, the throughflow analysis is developed. This is based on a rigorous passage averaging technique to derive throughflow equations valid inside a blade row. The advantages of this approach are that the meridional streamsurface does not have to be of a prescribed shape, and by introducing density weighted averages the continuity equation is of an exact form. Included in the equations are the effects of blade blockage, blade forces, blade-to-blade variations and loss. The solution of the equations is developed for the well-known streamline curvature method, and the contributions from these extra effects on the radial equilibrium equation are discussed. Part II of the paper incorporates the analysis into a quasi-three-dimensional computing system and demonstrates its operational feasibility.


2011 ◽  
Vol 88-89 ◽  
pp. 549-553
Author(s):  
Wen Xian Tang ◽  
Cheng Cheng ◽  
Yun Di Cai ◽  
Fei Wang

According to the design procedure of wind turbine blade, a design method that can make CAD software joint used was brought up. Wilson method was used to design and calculate the main data of blade. On this basis, the three-dimensional solid model of wind turbine blade could get by using and playing the function of different CAD software. This study provided a reference for the design of wind turbine blade and other similar complicated structures, which settles the basis for the further analysis of blade.


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