Evaluation of a 3D Viscous Code for Turbomachinery Flows

Computational Fluid Dynamics (CFI)) codes play an increasingly important role in the design and development of nirbomachinery for modern gas turbine engines. As a result additional emphasis is being placed on the evaluation of the codes to ensure that they are working correctly and to indicate the accuracy which is likely to be achieved in practice. At DERA a programme of work has been carried out to evaluate the TRANSCode 3D viscous flow code, which was developed from the BTOB3D solver written by Dawes in 1986. A three part strategy for the validation and calibration of the code was adopted, covering comparisons with boundary layer test cases, Q3D compressor cascades and full 3D cases. The results indicated that the grids currently employed for turbomachinery flows limit the accuracy achieved for cases where there is significant laminar flow. For turbulent flows the Baldwin-Lomax turbulence model gives reasonably accurate results for 2D flows in near equilibrium, but it is less satisfactory for more complex flows, when the concept of a simple 2D boundary layer does not apply, and for strong shock wave/boundary layer interactions. Overall it is considered that the code is a valuable tool for turbomachinery analysis and design, but solutions must be assessed with care. Alternative turbulence models and other developments are being pursued for future versions of the code.