Aerodynamic study of a vane-cascade swirl generator

The air how through a vane-cascade swirl generator is examined both experim entally and numerically to characterize the inlet combustion air flow enter ing a reference spray combustion facility at NIST. A three-dimensional mode l is used to simulate the aerodynamics in the 12-vane-cascade swirl generat or that imparts the desired degree of angular momentum to the air in the an nulus leading into the reactor. A numerical simulation using the renormaliz ation group method (RNG) k-epsilon turbulence model results in a velocity p rofile consistent with experimental measurements, and correctly predicts a recirculation zone that is experimentally observed at the exit of the annul ar passage. The standard k-epsilon turbulence model does not compare as wel l with the experimental data and fails to predict the recirculation zone at the exit. This work is part of a larger project at NIST in which benchmark data are collected for input and validation of multiphase combustion model s, and the results presented provide a well-characterized inlet condition f or the spray combustion reactor. The good agreement between the experimenta l data and the simulation with the RNG k-epsilon turbulence model provides further validation for this model in confined, annular flows. (C) 2000 Else vier Science Ltd. All rights reserved.