Discrete particle behavior in solid-liquid concave-wall jet

Abstract

The aim of this paper is to reveal the solid-liquid separation mechanism in concave-wall jet. The discrete particle experiments and numerical simulations were performed to study the large particle behavior near concave-wall. The results show that the particle behavior is divided into two stages by the first collision point of particle-to-wall and the wall shear stress at the collision point quickly changes from zero to peak. The iterative formulae for particle position coordinates are used and 27.88° is obtained as the maximum of circumferential collision position when the jet width is 20 mm. Before the first collision, the particle tangential velocity is constant and the wall shear stress is 0. After the first collision, the wall shear stress and tangential velocity decrease with time. The distance of particle-to-wall is within 0.1 times of jet width. Low-frequency contact of particle-to-wall is the collision and the particle Reynolds number often exceeds 400. The large particle behavior is affected by the shape of jet inlet cross-section. Comparing to the square inlet cross-section, the particle cumulative probability of rectangle inlet cross-section is lower at the same residence time, the local maximum of turbulent kinetic energy and wall shear stress decrease 5.3 % and 5.9 %, respectively.