Advanced Transonic Fan Design Procedure Based on a Navier-Stokes Method

Abstract

A fan performance analysis method based upon 3D steady Navier-Stokes equations is presented in this paper. Its accuracy is established through extensive code validation effort. Validation data comparisons ranging from a 2D compressor cascade to 3D fans are shown in this paper to highlight the accuracy and reliability of the code. The overall fan design procedure using this code is then presented. Typical results of this design process are shown for a current engine fan design. This new design method introduces a major improvement over the conventional design methods based on inviscid flow and boundary layer concepts. Using the Navier-Stokes design method, fan designers can confidently refine their designs prior to rig testing. This results in reduced rig testing and cost savings as the bulk of the iteration between design and experimental verification is transferred to an iteration between design and computational verification.

1995 ASME Gas Turbine Award Paper: Development and Application of a Multistage Navier–Stokes Flow Solver: Part II—Application to a High-Pressure Compressor Design

“…A flag is an integer value associated with each grid node that denotes the boundary condition to be applied. Examples include viscous wall, symmetry plane, periodic boundary, mass flow injection or extraction, and flow obstruction (Rhie, 1994). The flag system allows for geometric details, such as rotor tip clearances and variable pitch stator endgaps to be easily incorporated into the computational model.…”

“…The long development time, high cost and limited performance gains associated with this design system hastened the development of a new design technology based on the full three dimensional equations of motion. Design methods based on solving the Navier-Stokes equations became accurate and practical in the 1990's for isolated cascades of airfoils such as fans (Rhie, 1994). Early work in developing multistage turbomachinery CFD was done by researchers such as Ni (1989), Dawes (1992), Denton (1992), Adamczyk (1990), Chima (1991), Hah (1991), andJennions (1993).…”

Analysis and design of a new updraft free-exit-flow low-head hydropower turbine system

“…However, it is inadequate for predicting turbulence characteristics in the near-wall regions, and has a poor performance in the regions with a high adverse pressure gradient, which can be found in highly loaded turbine blades. In such a situation, a conventional mixing length model is used in the near-wall regions to improve the accuracy of turbulence prediction (Rhie et al 1993).…”