Experimental Research Of Gas Mixing And Numerical Simulation For Gas-Solid Two Phases Flow In A Spouted-fluidization Bed

A spouted-fluidization bed has extensive application on the industry. However, so far people still lack systematic study for the hydrodynamics characteristics in the bed. So it affects the choosement of structure pattern and parameters for spouted-fluidization bed equipments. The dissertation studies the characteristics of gas mixing and the gas-solid two phases flow in spouted-fluidization bed with experiment and numerical simulation methods.In experiment, gas mixing in spouted-fluidization bed was investigated by simultaneously injecting different tracer gas into the spout region and the annular region, respectively. The concentrations of tracer gas at various bed locations were obtained. A high-resolution digital camera was used to record the flow patterns. Effects of two most important operating parameters (spouting gas velocity and fluidizing gas flow rate) on gas mixing were examined with flow patterns. The results show that the distribution of tracer gas concentration at various bed locations differs greatly and decreases with bed height .In the stable flow gas transfer from the spout region to the annular region is promoted by increasing spouting gas velocity. Gas transfer from the annular region to the spout region and gas mixing in the annular region are promoted by increasing fluidizing gas flow rate. In the unstable flow the radial distribution of tracer gas concentration is asymmetry.In numerical simulation, the dissertation held a cold-state numerical simulation for the gas-solid two phases flow in spouted-fluidization bed with FLUENT CFD software. The numerical simulation displayed completely the formation, development, broken up of the bubble as well as the formation, development, disappearment of the ejection until the gas-solid steady flow in the spouted-fluidization bed. The numerical simulation results are basically in accordance with the experiment.The dissertation carried on numerical simulations based on different spouting gas flow rate and fluidizing gas flow rate, and made the analysis and comparisons to simulation results,generalized influences that spouting gas flow rate and fluidizing gas flow rate exert on the gas-solid two phases flow in spouted-fluidization bed.