Blade Row Interaction in a High-Pressure Steam Turbine

Chaluvadi, V. S. P.; Kalfas, A. I.; Hodson, H. P.; Ohyama, Hiroharu; Watanabe, E.

doi:10.1115/1.1518504

Cited by 40 publications

(17 citation statements)

References 17 publications

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“…Finally, validation-calibration of CFD codes for predicting the extremely challenging areas of separated flows can be also carried out (Pachidis et al, 2006). The increased computational power available nowadays throughout the research community has increased the application of high-fidelity numerical approaches on every kind of flow prediction, starting from pure aerodynamic phenomena occurring at inlets or compressors and extending them in combustion or turbine cooling research, employing multidisciplinary tools of chemical or heat transfer nature (Chaluvadi et al, 2003;Ramakrishna et al, 2009;Ummiti et al, 2009). In case of far off-design turbomachinery performance studies such as the above-described ones, the availability of experimental datasets is the only aspect that prevents the numerical tools from being further validated and at a second stage further improved.…”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Investigation of a Compressor Cascade at Highly Negative Incidence

Zachos

Grech

Charnley

et al. 2011

Engineering Applications of Computational Fluid Mechanics

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ABSTRACT:The performance prediction of axial flow compressors and turbines still relies on the stationary testing of blade cascades. Most of the blade testing studies are done for operating conditions close to the design point or in off-design areas not too far from it. However, blade-and consequently engine-performance remain unexplored at relatively far off-design conditions, such as windmilling or sub-idle. Such regimes are dominated by blade operation under extremely low mass flows and rotational speeds that imply highly negative values of incidence angle, thus totally separated flows on the pressure side of the blades. Those flow patterns are difficult to be measured and even more difficult to be numerically predicted as the current modelling capability of separated internal flows is of limited reliability. In this paper, the performance of a 3-dimensional linear compressor cascade at highly negative incidence angle is initially experimentally investigated. The main objective of the study is to derive the total pressure loss and outlet flow angle through the blades and use the data for the validation-calibration of a numerical solver enhancing its capability to predict highly separated flows. The development of the CFD model and the simulation strategy followedare also presented.The numerical results are compared against the derived test data demonstrating a good agreement. In addition, most trends of the properties of interest have been captured sufficiently, therefore the physical phenomena are considered to be well captured, allowing the numerical tool to be used for further studies on similar test cases.

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Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Investigation of a Compressor Cascade at Highly Negative Incidence

Zachos

Grech

Charnley

et al. 2011

Engineering Applications of Computational Fluid Mechanics

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“…The 2-stage high pressure steam turbine used in the present work is described in great detail by Chaluvadi et al [7][8] . Its aerothermodynamic properties as well as some geometrical features are summarized in Table 1.…”

Section: Geometry Scanningmentioning

confidence: 99%

“…The researcher is provided with an improved understanding of the on-the-field engine. This paper examines the camber line deformation effect on the performance of the 2-stage experimental axial steam turbine [7][8] based on a high fidelity CMM inspection of the actual geometry. A statistical study of the geometrical errors aims to unveil the nature and the significance of the aforesaid inaccuracies.…”

Section: Introductionmentioning

confidence: 99%

Turbine Blading Performance Evaluation Using Geometry Scanning and Flowfield Prediction Tools

Zachos

Παππά

Kalfas

et al. 2008

JPES

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This paper investigates the effect of blade deformation, caused by manufacturing inaccuracies, on the performance of a 2-stage axial steam turbine. A high fidelity 3D coordinate Measurement Machine has been employed to obtain the exact geometrical model of the blades. A Streamline Curvature solver was used to predict the overall performance of the turbine. During the manufacturing process of the casts and of the blades themselves, several types of errors can occur which lead to a different geometry from that envisaged by the designer. The main objective of this study is to investigate the effect of those errors on the performance of a 2-stage experimental axial steam turbine. A high fidelity measurement of the actual geometry of both stator and rotor blades has been carried out, using a 3D Coordinate Measurement Machine. The cross sections of the blades obtained by the measurement were compared with those produced by the design process to evaluate the change in blade inlet/exit angles. In addition, the geometrical deviations from the initial design have been subjected to a statistical study in order to locate the nature of the error. The actual (measured) model has been used as input into a Streamline Curvature solver to evaluate its performance. Finally, a comparison with the performance plots of the original geometry has been carried out. A measurable change of efficiency as well as in the total power delivered by the turbine was found. This suggests that the accumulated error caused during the manufacturing procedure plays a significant role in the overall performance of the machine by making it less efficient by more than 1%. Reverse engineering techniques can be applied to predict and alleviate these errors leading thereby to a final design of each stage with improved performance.

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“…This is caused by the vortex transportation in the rotor. Stator passage vortex has two counter-rotating legs -rotor suction side and rotor pressure side (according to [12]) -because the vortex is chopped by rotor blade and distributed to both suction and pressure sides of the blade. On the blade suction side, the stator passage vortex (counterclockwise) interacts with the horseshoe vortex (counterclockwise) and is shifted towards the mid-span by the rotor passage vortex (clockwise).…”

Section: Epj Web Of Conferencesmentioning

confidence: 99%