Using fluid velocity in lieu of impeller speed for dimensional analysis and a method for estimating fluidborne noise due to flow turbulence within centrifugal pumps

An empirical method for estimating fluidborne broadband noise associated with flow turbulence within centrifugal pumps is considered in this paper. Given the flow rate, developed head and the operating speed, an estimate of the pump's fluidborne broadband noise can be made using the method. The method is developed by correlating the noise performance of centrifugal pumps with different specific speeds to the pump parameters (i.e. impeller dimensions and hydraulic performance). The correlation is achieved by using dimensional analysis, where the Buckingham Pi theorem is applied to relate the acoustic signature of the pump to the characteristics of the pump. Similar analysis had previously been performed on centrifugal pumps using air as a medium. The studies evaluated pumps at different flow coefficients of the same pump speed. To some extent, aerodynamic noise was correlated to the impeller tip speed. However, simply using the impeller tip speed may not be accurate. This paper offers an alternate method in relating noise, where instead of the impeller speed, the actual fluid velocity is calculated and used in the analysis.