Characterization of the Inlet Combustion Air in NIST's Reference Spray Combustion Facility: Effect of Vane Angle and Reynolds Number

Abstract

The airflow through a 12-vane cascade swirl generator is examined numerically to characterize the inlet combustion air in the reference spray combustion facility at NIST. A three-dimensional model is used to simulate the aerodynamics in the swirl generator that imparts the desired degree of angular momentum to the air in the annulus leading into the reactor. A parametric study is presented in which the effects of the vane angle and Reynolds number are examined. Reynolds numbers ranging from 5,000 to 30,000, and vane angles ranging from 30 to 60, are investigated. For a vane angle of 50, which is the current operating condition of the swirl generator, a recirculation zone develops at the exit of the annulus for Reynolds number, Re ≈ 9500. The Renormalization Group method (RNG) k-e turbulence model is used to model the transport, production, and dissipation of turbulence due to its superior performance (relative to the standard k-e turbulence model) for this type of flow.