An analysis of the flow and sound fields of a centrifugal fan located near a wedge

Abstract

Centrifugalfans are widely used and the noise generated by these machines causes one of the most serious problems. In

An Application of the Acoustic Similarity Law to the Numerical Analysis of Centrifugal Fan Noise

“…DVM is generally used for the unsteady flow analysis. It has been applied to the flow field analysis of centrifugal fans (15) - (17) . The centrifugal fan studied in this paper ( Fig.…”

“…The four right-hand side terms represent velocities induced by point source, bound vortices, wake vortices, and source panel, respectively (15) . The strengths of the bound and wake vortices, and the source panel can be calculated with the boundary condition that the normal component of the velocity at x c j ( j = 1,2,···,nc), where nc is the number of elements for each blade, is zero and with Kelvin's condition, which means the conservation of total circulation (15), (16) .…”

“…The strengths of the bound and wake vortices, and the source panel can be calculated with the boundary condition that the normal component of the velocity at x c j ( j = 1,2,···,nc), where nc is the number of elements for each blade, is zero and with Kelvin's condition, which means the conservation of total circulation (15), (16) . The convection of the vortices shed at the trailing edge is calculated by 2nd order Runge-Kutta method.…”

“…The convection of the vortices shed at the trailing edge is calculated by 2nd order Runge-Kutta method. The forces on the blades are calculated by the unsteady Bernoulli's equation (15) .…”

“…Lowson's method can be used to predict acoustic field when a dipole moves at an infinite boundary, therefore, cannot consider scattering and diffraction. However, Lowson's method can be easily used for the noise source identification and for the prediction of acoustic pressures (15), (16) . In this paper, for the Weidemann's centrifugal fan, the flow field analysis and acoustic pressure field prediction are performed.…”