Impingement on blade surface by fine particles with high velocity is commonly seen in steam turbines, gas turbines and compressors, which affect the service life and reliability of the equipment. Study on particles' rebound characteristics is of great significance to reduce the blade erosion and to control particle trajectory. Based on the nonlinear explicit dynamics analysis software ANSYS/LS-DYNA, the impacts of fine spherical particles with different diameters (20 to 500um) on a typical martensitic stainless steel (AISI 403) target with high velocity (50 to 250m/s) have been systematically studied. The influences of incident velocities, impact angles, particles sizes on its rebound characteristics, relative impact depth, and relative dissipated energy have been analyzed. Results show that velocity restitution coefficient e decreased with the impact angle β_l, the incident velocity V_1, and the particle size d_p. However, the role of particle size on the velocity restitution coefficient seemed to be far less than that of the other two factors. Both of particle's tangential and normal velocity coefficient of restitution declined with the increasing impact angle in most cases. However, when the incident velocity V_1=200m/s and the impact angle β_l＞45°, the tangential velocity restitution coefficient e_t of 100 urn and 200 urn particles increased with the increase in the impact angle β_l. The reason might be that the relative impact depth d_(rel) was located a zone ranged from 0.1515 to 0.1677, where the tangential rebound behavior could be enhanced. Most of the variation of the tangential and normal velocity restitution coefficient along β_l decreased with the increase in the particle diameter. However, when V_1=200m/s and β_l＞15°, the tangential reflected velocity of the larger particles was enhanced gradually. In addition, the values of the relative impact depth d_(rel) increased with the increasing impact angle and incident velocity, and it increased with the increasing particle diameter in most cases. The relative dissipated energy of particles steadily increased with the impact angle and incident velocity, respectively. Particle diameter had little effect on energy dissipation in comparison with the impact angle and incident velocity.
展开▼
