Three Dimensional Flow Investigation in One and a Half Stage Axial Turbine

In this study, three dimensional flow analysis of one and a half stage axial turbine is investigated. The objective of this study is to analyse the effect of rotor stator interaction and the resulting unsteadiness. This includes the effect of first row of Nozzle guide vane (NGV) wakes on rotor blades, secondary vortical flow prediction, influence of rotor wakes on the flow pattern of second stator, appreciation and application of techniques to model the exact blade counts across the rotor-stator interfaces. We employ a three-dimensional finite-volume based solver to simulate the flow in the turbine using SST model to account for turbulence effects. Sliding mesh technique is used to allow the transfer of flow parameters across the sliding rotor/stator interfaces. In order to model a single passage configuration, profile transformation and time transformation method is used. The flow physics for the visualization and understanding of flow behavior in a 3D turbine cascade is explained in detail and validated with the previous experimental and numerical studies. The study provides application of computationally efficient methods for simulating the fluid flow in a turbine which contain unequal number of rotor and stator blades.

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Flow Behavior Around Stayvanes and Guidevanes of a Francis Turbine

Journal of Fluids Engineering ◽

10.1115/1.2817487 ◽

1996 ◽

Vol 118 (1) ◽

pp. 110-115 ◽

Cited By ~ 4

Author(s):

Toshiaki Suzuki ◽

Tomotatsu Nagafuji ◽

Hiroshi Komiya ◽

Takako Shimada ◽

Toshio Kobayashi ◽

...

Keyword(s):

Viscous Flow ◽

Flow Behavior ◽

Flow Analysis ◽

Three Dimensional ◽

Flow Characteristics ◽

Francis Turbine ◽

Good Prediction ◽

Three Dimensional Flow ◽

Dimensional Flow ◽

Pressure Distributions

The three-dimensional computation of steady and incompressible internal flows is of interest in numerical simulations of turbomachinery, and such simulations are currently under investigation, from inviscid to viscous flow analyses. First, surface pressure distributions have been measured for the stayvanes and the guidevanes of a Francis turbine. They are presented to verify the numerical results. Second, both inviscid and viscous three-dimensional flow analyses have been made, so as to predict the flow behavior in the same domain. Comparison of the measured pressure distributions to the predicted pressure distributions has been made to study the usefulness of the present simulations. It can be pointed out that a global analysis which includes a runner flow passage, except runner blades, is necessary to predict the three-dimensional flow characteristics and that inviscid flow analysis has the capability of good prediction for flow without separation. Viscous flow analysis gives similar results, though it is necessary to investigate further the improvement of prediction accuracy. Flow characteristics around the stayvanes and the guidevanes are also discussed.

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Optimization of the Three-Dimensional Flow Path in the Scroll-Nozzle System of a Radial Inflow Turbine

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.3239600 ◽

1984 ◽

Vol 106 (2) ◽

pp. 511-515 ◽

Cited By ~ 1

Author(s):

E. A. Baskharone

Keyword(s):

Flow Analysis ◽

Three Dimensional ◽

Inviscid Flow ◽

Three Dimensional Flow ◽

Multiply Connected ◽

Dimensional Flow ◽

Nozzle Configuration ◽

Flow Domain ◽

Radial Inflow Turbine ◽

Compressibility Effects

A three-dimensional inviscid flow analysis in the combined scroll-nozzle system of a radial inflow turbine is presented. The coupling of the two turbine components leads to a geometrically complicated, multiply-connected flow domain. Nevertheless, this coupling accounts for the mutual effects of both elements on the three-dimensional flow pattern throughout the entire system. Compressibility effects are treated for an accurate prediction of the nozzle performance. Different geometrical configurations of both the scroll passage and the nozzle region are investigated for optimum performance. The results corresponding to a sample scroll-nozzle configuration are verified by experimental measurements.

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The Influence of Endwall Contouring on the Performance of a Turbine Nozzle Guide Vane

Volume 1: Turbomachinery ◽

10.1115/98-gt-071 ◽

1998 ◽

Cited By ~ 2

Author(s):

Vincenzo Dossena ◽

Antonio Perdichizzi ◽

Marco Savini

Keyword(s):

Flow Field ◽

Gas Turbine ◽

Guide Vane ◽

Three Dimensional ◽

Angle Distribution ◽

Secondary Effects ◽

Three Dimensional Flow ◽

Nozzle Height ◽

Dimensional Flow ◽

Endwall Contouring

The paper presents the results of a detailed investigation of the flow field in a gas turbine linear cascade. A comparison between a contoured and a planar configuration of the same cascade has been performed, and differences in the three-dimensional flow field are here analyzed and discussed. The flow evolution downstream of the trailing edge was surveyed by means of probe traversing while a 3-D Navier-Stokes solver was employed to obtain information on flow structures inside the vaned passages. The experimental measurements and the numerical simulation of the three-dimensional flow field has been performed for two cascades; one with planar endwalls, and the other with one planar and one profiled endwall, so as to present a reduction of the nozzle height. The investigation was carried out at an isentropic downstream Mach number of 0.6. Airfoils of both cascades were scaled from the same high pressure gas turbine inlet guide vane. Measurements of the three-dimensional flow field have been performed on five planes downstream of the cascades by means of a miniaturized five-hole pressure probe. The presence of endwall contouring strongly influences the secondary effects; the vortex generation and their development is inhibited by the stronger acceleration taking place throughout the cascade. The results show that the secondary effects on the contoured side of the passage are confined in the endwall region, while on the flat side the secondary vortices display characteristics similar to the ones occurring downstream of the planar cascade. The spanwise outlet angle distribution presents a linear variation for most of the nozzle height, with quite low values approaching the contoured endwall. The analysis of mass averaged losses shows a significant performance improvement in the contoured cascade. This has to be ascribed not only to lower secondary losses but also to a reduction of the profile losses.

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