关键词: 气液分离, 旋流板, 分离效率, 压降

Abstract: The propagation and decay of concentration wave in liquid–solid pulsed fluidized beds is studied by numerical simulation and experimental validation. When the semi-on period and semi-off period are much longer than the particle relaxation time, the difference between the inertia forces of the two phases is small compared with the gravity of the solid phases except a short period in the order of the particle relaxation time after a sudden change of fluidizing velocity, the momentum equations of the two phases in pulsed fluidized beds can be simplified to a local equilibrium model. The simulation difficulty caused by the ill-posedness of the basic two-fluid model can be avoided using the concentration wave equation. The liquid–solid flow pulsation induced by the fluidizing fluid varying in both sinusoidal and step-wise patterns is simulated using the five order WENO scheme for spatial derivative and three order TVD Runge–Kutta method for time derivative. The front-fixing method is used to handle the moving upper boundary. The simulation result of fluidizing velocity varying in step-wise pattern is validated and matches the experimental data well. In the pulsed fluidization, the concentration wave decays due to the interaction between the concentration discontinuity and dilatation waves.

Key words: liquid–solid pulsed fluidized bed, concentration wave, numerical simulation, weno scheme