Patent ID: 6278958
Filing Date: 2001-08-21
Classification: G01H,G01N

Abstract:
A method for predicting a noise intensity emitted from a fan, comprising steps for:analyzing a flow field around the fan on the basis of a fan shape and operating conditions;obtaining a noise source value of the fan from force data of blades at a given time in the analyzed flow field; andcalculating a noise intensity from the noise source value;wherein said step for analyzing a flow field around the fan further comprises receiving data about the fan shape and the operating conditions and analyzing a flow field at every time with a vortex method in consideration of rotation of the fan; andwherein said step for obtaining a noise source value of the fan further comprises the steps for:reading data about the flow field along with data about the relevant fan and the relevant impeller;forming a noise source mesh over that relevant impeller or the relevant roter, which are main sources of noise generated in the fan;calculating a sound pressure by acoustic analogy;determining whether a sound field is being analyzed in the domain of frequency or the domain of time; andcalculating an observer time in consideration of a retarded time, and calculating noise source values at every time in consideration of the retarded time if the sound field is being analyzed in the domain of time, while converting the noise source values into that in the domain of frequency and obtaining a noise source value of a designated frequency from them if the sound field is being analyzed in the domain of frequency.