Abstract

This research work reports the study and investigation of aerodynamically generated noise characteristics of the fan using hybrid numerical approach. Experimental work is also reported and validated with numerical simulation results. The experiment is conducted for determination of sound power radiated by the fan. This experiment is carried out in the reverberant and anechoic chambers as a test environment. The axial subsonic fan is considered for the study. Detailed experimental work is reported in the first section, in the second section numerical simulation and analysis is reported. Flow analysis is carried out using unsteady Navier Stokes based equations with Large Eddy Simulation scale resolving turbulence model in commercial solver Ansys Fluent. Fluctuating components of velocity and density are computed for further calculation of Acoustics. Flow results from the simulation are compared with flow results measured in the experiment, As the aerodynamic performance of the fan is validated, then followed by aeroacoustics analysis performed in MSC Actran Acoustics solver. Lighthills analogy is used to compute the flow noise generation and propagation terms. Sound power characteristics is studied with the help of one third octave band and Narrow band analysis. Overall sound power is computed in MSC Actran is compared with experiment. Also, the sound power computed in Ansys Fluent is compared with experiment. This work also reports the detailed computational methodology for fan noise prediction for any type of fan applications.