Numerical Boundary Conditions Simulating the Interaction Between Upstream Disturbances and an Axial Compressor

Abstract

New small disturbance and area reduction compressor face boundary conditions that model the unsteady interactions of acoustic disturbances with an axial compressor are presented. The new small disturbance boundary condition is formulated to correct the deficiencies associated with the Paynter small disturbance model. The area reduction boundary condition provides a simple approach for the inlet outflow boundary. Both of these boundary conditions are implemented in one-dimensional and axisymmetric turbulent flow models of the inlet/compressor experiment at the University of Cincinnati. Acoustic reflections from the compressor face boundary conditions are compared against the measured experimental reflection characteristics of the axial compressor. The performance of the boundary conditions is also compared against existing boundary conditions such as the Paynter small disturbance boundary condition. These comparisons show that the new small disturbance boundary condition provides the best accuracy in terms of the prediction of the reflected disturbance from the interaction of an acoustic disturbance with a compressor. The results also show that the area reduction boundary condition produces acoustic reflections that agree well with the experimental data.