In the process of hydraulic fracturing,under the coupling effect of complex solid-liquid two-phase flow and severe loads,the weak parts of high-pressure manifold such as elbows,tees and joints suffer from severe erosion wear for a long time,which would easily lead to the fracture and damage of the pipe fittings and pose a serious threat to the personnel and equipment on site.The erosion wear experiments involving applied stress were carried out.According to the test results,a new erosion model considering the effect of stress state was developed based on E/CRC erosion model,and the agreement between the new model and the erosion test data can reach more than 95%.The three-dimensional numerical simulation of the erosion performance of the high-pressure pipe fitting was carried out using the computational fluid dynamics-discrete phase model (CFD-DPM),and the severity and spatial distribution of erosion wear under different fracturing conditions were investigated.The results show that the main erosion zone is located on the elbow extrados near the elbow exit,and the maximum erosion rate of the elbow is also located there.Under the action of the secondary flow vortex on the inside of the elbow,driven by the secondary flow vortices inside the elbow section,some particles move and accumulate in the inner wall of the downstream straight pipe near the elbow exit.Accordingly,the secondary erosion region is made apparent in this area.With the increase of the particle Stokes number coefficient,the area of the main erosion zone increases and the area of the secondary erosion zone decreases.In addition,after embedding the new erosion model,it can be observed that the erosion wear rate at the elbow of the high-pressure elbow increases significantly as the operating pressure increases.