Flows In Blade Rows Research Articles

Calculation of Three-Dimensional, Inviscid, Rotational Flow in Axial Turbine Blade Rows

This paper describes a fully explicit, time marching, corrected viscosity, finite volume method to solve the Euler equations in a cylindrical coordinate system. The rotational character of the incoming flow can be taken into account. On the outflow boundary, a generalized radial equilibrium condition is imposed. Blade rows of complex geometry can be handled. At present, the method has been used to calculate the flow through the nozzle vanes of the VKI low-speed turbine facility. The calculated results show good agreement with the experimental data for the spatial distribution of both the static pressure and the flow angle.

Overall Aerodynamic Performance of an Annular Flat-Plate Airfoil Cascade

THE aerodynamic design of turbomachiner y blading is specified by means of design systems wherein the flow is assumed to be two-dimensional with losses determined from empirical correlations. However, with the continuing requirements for improved efficiency and increased thrust-to-weight ratio, it is evident that new analyses that consider the fundamental three-dimensional flow phenomena existing in blade-row flow passages must be developed, verified by concise data, and subsequently implemented in the design process. Numerical solutions are currently being developed to predict the three-dimensional flow through turbomachine blade rows. To overcome the complexities associated with the flow conditions and the internal geometries, these numerical solutions of necessity involve many computational and physical assumptions. This paper describes experiments performed in a large-scale, subsonic annular cascade facility specifically designed to provide three-dimensional aerodynamic data suitable for code verification. In particular, to minimize the complexities associated with cascade geometry and complex airfoil profiles, the detailed overall threedimensional aerodynamic performance of an extensively instrumented flat-plate airfoil cascade has been experimentally determined over a range of incidence angle values. All of the resulting data are analyzed and correlated with appropriate predictions. Contents

A Surface Vorticity Analysis of Three-Dimensional Flow through Strongly Swept Turbine Cascades

The two-dimensional surface vorticity theory of Martensen is extended to deal with the full three-dimensional flow through a swept turbine cascade, including end effects. Basic concepts of surface vorticity theories are dealt with initially, as also are three three-dimensional flow considerations for swept cascades. The paper goes on to develop two theoretical models for the representation of swept blade row flows. The first model assumes that the blade bound vorticity remains constant across the span of the blade. In the second model, this assumption is relaxed so that the blade bound vorticity is allowed to vary in the spanwise direction. In both cases the theories are applied to turbine nozzle cascades. Some of the solutions obtained are compared with experimental tests which were the subject of a previous paper.