The main objective of this study is to simulate the dynamic behavior of entrained solid-particles in a pipe flow and its role in the erosion process. A detailed parametric study changing the solid particle diameter, flow rate, pipe diameter, fluid viscosity, and solid particle density was performed to find the critical parameter that affects erosion in a pipeline. To fulfill the objectives of the study, a Computational Fluid Dynamics (CFD) simulation was conducted for water-solid flow within a complex pipeline geometry with rapid alterations in flow directions. The simulation was performed using ANSYS Fluent code. Three different turbulent models: k-epsilon (k-ε), k-omega (k-ω) and Shear Stress Transport (SST) have been compared to find out the best turbulent model validating the simulation results with the experimental results. Flow instability, turbulence, and erosion have been quantified for different sand particle size of 10, 70, 100 and 200 microns and different inlet liquid velocities of 20, 25, 30, 35 and 40 m/s. The inlet velocity has a remarkable effect in the erosion rate. We have observed that if the inlet velocity is increased from 20 m/s to 40 m/s, the erosion rate is increased from 1.73 x10−4 kg/m2.s to 2.11×10−3 kg/m2.s, respectively at a constant particle size of 200 μm. We have also observed that if the solid particle size is increased from 70 μm to 100 μm, the erosion rate is increased from 5.79 × 10−4 kg/m2.s to 8.03 × 10−4 kg/m2.s, respectively, at a constant velocity of 40 m/s. Previous studies have studied the effect of sand particles on the erosion of an elbow; however, this work introduces a complex pipeline which has three elbows and an arch. This study can be utilized for quantifying the erosion rate in complex pipeline geometry with larger pipeline diameters and varying fluid properties.