Influence of blade number on flow-induced noise of centrifugal pump based on CFD/CA

In order to study the influence of blade number on flow-induced noise of the centrifugal pump, a computational method based on the combination of computational fluid dynamics and computational acoustics was proposed to numerically calculate the acoustic field of the centrifugal pump. Taking the principle of single variable, the number of different blades was selected as the research variable, and the three-dimensional unsteady constant value of the flow field in the centrifugal pump was calculated by using the Reynolds time-average equation of SST k-omega turbulence model. Combining with the results of flow field calculation, the acoustic calculation was carried out by using the idea of acoustic-vibration coupling. The results showed that the baffle tongue was the main noise source of the centrifugal pump. The main reason was that due to the interaction between the impeller and the tongue during the operation of the centrifugal pump, the acoustic pressure values of the model pumps at the tongue position were maximized. With the increase of the number of blades, the acoustic pressure level of the model pump first decreased and then increased, and reach the minimum value when the number of blades was 6, which indicated that the number of 6 blades was the optimal value for reducing the flow-induced noise of the centrifugal pump. In order to verify the reliability of numerical calculation, a centrifugal pump flow-induced noise test platform was set up to carry out verification tests on each model pump. The error between the test value and the simulated value was analyzed, and the acoustic pressure level curves at each monitoring point of each model pump under different working conditions were obtained. The test results showed that the acoustic pressure level curves of the test and simulated values had the same trend, which further verified the accuracy and feasibility of the proposed joint calculation method.