Sand particles present in the fluid flows extracted from oil wells causes many problems for oil and gas production companies. Collision of sand particles to the wall of oil transfer pipes and process equipment reduces wall thickness which is considered as a cause of erosion. One of the consequences of this problem is frequent failures and loss of valuable production time. Bends installed in the path of oil and gas pipelines are at risk of such erosion as mentioned. This paper is a study of computational fluid dynamics to predict erosion in the bend geometry. It uses Lagrangian approximation which includes modeling of continuous flow of fluid, Lagrangian particle tracking and calculation relating to erosion. In this work, the effect of various parameters such as flow velocity, particle diameter, and bend geometry and particle-fluid density ratio on the particle motion and consequently erosion resulting from the collision of particle to bend wall is studied.