PIV seeding particles selection is flow fielddependent,so that the selecting suitable seeding particles to flow field in centrifugal pumps is the key thing to allow the accuracy of PIV measurement to be guaranteed.Based on the particleliquid twophase turbulent flow theory,the forces acting on the seeding particles,mainly including the viscous resistance and the forces caused from centrifugal acceleration field in a centrifugal pump were analyzed.Then the Lagrange equation of a seeding particle was established by introducing an external potential force into the BBO equation.Using the Fourier integral transform,a formula,which is applicable for PIV measurement of flow field in a centrifugal pump,for calculating the seeding particle tracing ability was deduced initially.Utilizing the PIV phaseaveraged measurement results of the flow field in a centrifugal pump,the seeding particle tracing ability was estimated.The results turned out the particle tracing ability in the radial direct is poorer than that in the circumferential one,thus the seeding particles should be selected according to the priority of tracing ability in the radial direction.Even though the results of PIV measurement are processed with a phaseaveraged technique,the velocity of seeding particles doesn′t represent the real velocity of fluid because of the effects of impeller rotation and streamline curvature,and causing a maximum error is as high as about 4.55%.The formula can be used to examine the reliability of seeding particles to improve the accuracy of PIV flow measurement in centrifugal pumps.
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