Numerical simulation of evaporating crossflow sprays in gas-solids circulating fluidized beds

A hybrid Eulerian-Lagrangian method has been applied to simulate the 3-D flow structure with an evaporating liquid spray (liquid nitrogen) injected into a gas-solids (FCC) circulating fluidized bed of rectangular cross-section. The gas-solid flows are simulated using the multi-fluid method while the sprays are described using Lagrangian trajectory method. Our simulation shows that the spray penetration is significantly affected by the solids loading. It is found that, due to the strong cross-flow convection, the temperature contours of gas and solids phases, as well as the vapor region, deviate away from the spray region. The simulation also shows that the spray evaporation leads to a very low solids concentration within the vapor region while there is a dense layer of solids surrounding the vapor region. These simulation results agree with our experimental observations and measurements.