Abstarct: pressure drop in the pipes has been studied by many scientists. Laboratory results and studies in this field show that the pressure drop in a pipe elbow is more than of the straight pipe with same size. As for extensive use of elbow pipes, Scientists have been looking for a way to reduce the pressure drop in the pipe elbow. Experiments show that in turbulent flow with high Reynolds number put the vane into the curved tubes leads to more uniform flow in the downstream of the bends and the effects of secondary flow, thereby reducing the pressure loss is reduced to a considerable extent. In this study, we tried to put the vane into the tube bends with a radius of curvature to the radius of the pipe elbows ,1.5, the effect of the vane position inside the tube elbow 90 degrees, with FLUENT flow simulation software has been investigated and optimized vanes pose to be determined within the knee. To do this, confusion results of different models were compared with the results of the modeling software giant vortices best results and compliance with laboratory results showed. Then change the curvature of the vanes from the center of the knee and the reduction in pressure drop compared with the model with no vane, the results showed a reduction in pressure drop in vaned models up to 50% pressure drop in the model with no vane. Different models in several high Reynolds numbers showed that the optimal radius of curvature of the vanes within the 90-degree vaned elbows is 1.125 times the radius of the pipe elbows.