Mixing Behaviors of Wet Granular Materials in Gas Fluidized Beds
نویسنده
چکیده
The mixing behaviors of dry and wet granular materials in gas fluidized bed systems were investigated computationally using the combined Computational Fluid Dynamics and Discrete Element Method (CFD-DEM). Dry particles were observed to mix fairly rapidly during the fluidization process due to vigorous relative motions between particles induced by the flow of gas. In contrast, due to the presence of strong cohesive forces arising from capillary liquid bridges between wet particles, the mixing efficiencies of wet granular materials under similar operating conditions were observed to be reduced significantly. Keywords—Computational Fluid Dynamics, Discrete Element Method, Gas Fluidization, Mixing, Wet particles
منابع مشابه
Effect of Bed Diameter on the Hydrodynamics of Gas-Solid Fluidized Beds
Effect of scale on the hydrodynamics of gas-solid fluidized beds was investigated in two fluidized beds of 152 mm and 78 mm in diameter. Air at room temperature was used as the fluidizing gas in the bed of sand particles. The Radioactive Particle Tracking (RPT) technique was employed to obtain the instantaneous positions of the particles at every 20 ms of the experiments. These data were u...
متن کاملSegregation Behaviour of Particles in Gas Solid Fluidized Beds at Elevated Pressure
A comprehensive mathematical model based on the discrete particle model and computational fluid dynamics was utilized to investigate mixing and segregation of particles in fluidized beds at high pressure. To quantify the extent of mixing in the bed, the Lacey mixing index was used. Simulations were carried out with different mass fractions of small particles at various pressures ranging from 1 ...
متن کاملEvaluation of Eulerian Two-Fluid Numerical Method for the Simulation of Heat Transfer in Fluidized Beds
Accurate modeling of fluidization and heat transfer phenomena in gas-solid fluidized beds is not solely dependent on the particular selected numerical model and involved algorithms. In fact, choosing the right model for each specific operating condition, the correct implementation of each model, and the right choice of parameters and boundary conditions, determine the accuracy of the results i...
متن کاملAutocorrelation spectra of an air-fluidized granular system measured by NMR
– A novel insight into the dynamics of a fluidized granular system is given by a nuclear magnetic resonance method that yields the spin-echo attenuation proportional to the spectrum of the grain positional fluctuation. Measurements of the air-fluidized oil-filled spheres and mustard seeds at different degrees of fluidization and grain volume fractions provide the velocity autocorrelation that d...
متن کاملCfd Analysis of Circulating Fluidized Bed Combustion
In this paper computational analysis of circulating fluidized bed combustion using the fluent software is analysed. This work is concerned about gas–solid two-phase mixtures flowing upwards through the fast beds. The procedures studied are applicable to all types of fluidized-bed boilers. The type of information resulting from various ways of analyzing the pressure and temperature in fluidized ...
متن کامل