For investigating the pressure pulsation characteristics of the unsteady flow in centrifugal pumps,a single-stage single-suction centrifugal pump was taken as an example to perform a numerical simulation by using the technology of large eddy simulation with sliding grid.The three dimensional flow field was simulated numerically with the blade wrap angle 95°,100°,105° and 108° respectively.The influences of the blade wrap angle on the centrifugal pump hydraulic performance,impeller exit jet-wake,pressure pulsation frequency spectrum characteristics at each measuring point and radial force of the impeller were analyzed.The results show that as the angle increases,the centrifugal pump hydraulic performance degradates.The angle increase will lead to the impeller outlet jet-wake flow structure.Under design conditions,near the volute tongue the pressure pulsation at measuring points is the strongest,at the spiral screw section along the flow direction,the pressure pulsation intensity gradually weaken,and at the impeller passage point along the flow direction,the pressure pulsation gradually enhances and reaches the maximum at the impeller outlet.The radial force of the centrifugal pump impeller decreases with the increase of angle.Therefore,appropriately increasing the wrap angle can improve the reliability of the centrifugal pump running.