Characteristic Study of Pressure Fluctuation in Centrifugal Pump

In order to reveal the characteristics of pressure fluctuation in centrifugal pump, based on finite volume method, RNG k–ε turbulence model and sliding mesh, the three-dimensional unsteady incompressible viscous flow in a low-specific-speed centrifugal pump is simulated numerically at different flow rates, wherein SIMPLE arithmetic is used to couple pressure and velocity. The calculation region consists of straight suction chamber, impeller and spiral casing. The results show that pressure wave presents periodic sine or cosine regularity in spiral casing, while the characteristic doesn’t appear in suction chamber. In suction chamber, the dominant frequency of pressure fluctuation is equal to rotational frequency of impeller. And in spiral casing, the dominant frequency of pressure fluctuation is equal to the product of rotational frequency of impeller and blade numbers. The dominant frequency of pressure fluctuation for each detection point is constant at any operation conditions. With the augment of operation flow rate, local average pressure in suction chamber will gradually increase, while local average pressure in spiral casing will gradually decrease. The pressure fluctuation at tongue will be more violent as flow rate increases. The pressure fluctuation in spiral volute will gradually decline along rotational direction of impeller.