Granular material conveying is a widely used process in industry, commonly found in gas-solid or liquid-solid two-phase flow conveying systems. In conventional horizontal pipe transport, particle deposition behavior can have a significant impact on transport efficiency and system stability, so reducing particle deposition is a key issue. The present study proposes a deflector vane-type swirl generator and investigates the effects of conveying velocity and particle size on the swirling flow conveying behavior using a coupled computational fluid dynamics-discrete element method. The results demonstrate that, from the perspective of the flow pattern of particles, when u(f) >= 3 m/s, the structure of an effective vortex field can be generated, which promotes the suspension of particles and improves the problem of particle deposition at the bottom of the pipeline. Swirling flow can significantly affect the distribution of particles within the pipe, with most of the particles distributed in the range of 0.8 < r/R < 1.0. Furthermore, the deposition efficiency of the particles exhibited periodic fluctuations along the axial direction. The smaller the particle size, the more pronounced the periodic fluctuation of the deposition efficiency, while the deposition behavior of large particles is relatively stable. The results of the study have the potential to provide theoretical guidance for the optimization of the design of swirling flow conveying equipment for practical industrial applications.