Abstract:The Phan Thien-Tanner (PTT) viscoelastic constitutive model was used to simulate the solid propellant 4∶1 contraction flow by CFD viscoelastic fluid software Ansys-Polyflow. The fluid streamline form, flow velocity and normal stress effect of the solid propellant slurry at the contraction port of the channel were studied under different relaxation time. Studies have shown that as the relaxation time increases, the Weissenberg effect of the fluid gradually increases, and the phenomenon of eddy currents at the corner of the contraction port is more obvious. At the entrance of the contraction channel, as the flow area is reduced, the fluid accelerates along the direction of the central axis to ensure fluid quality conservation, and the velocity gradient direction is consistent with the flow direction of the fluid at the central axis, where an extensional flow with a large strain rate is generated. The flow away from the central axis and near the wall is dominated by shear flow.