氯化稀土溶液射流热解反应器流体动力学的数值模拟

摘要

基于直接热解氯化稀土溶液制备稀土氧化物技术，设计一种新型射流热解反应器，并采用CFD方法对反应器内压力、速度等流体动力学特性进行了数值模拟。结果表明：射流热解反应器喉管处自主产生的动压(p)与燃气的进口速度(v)呈二次函数关系(p=0.06v2+0.23v−4.49)。欲使氯化稀土溶液热解反应充分利用燃料燃烧所产生的热量，需在进料口施加一定的压力，此压力与燃料的进口速度呈二次函数关系(p=v2+3v−4.27)。进料口的直径增加到原来的1.25和1.5倍，稀土氧化物的吸入量分别增加了30%和60%以上。整个反应器内流体流动主要受燃料的入口速度影响，且在喉管附近速度形成波峰，随物料加入速度急剧下降，到射流反应器末端速度趋于平缓。%Rare earth oxide was prepared via direct pyrolysis of rare earth chloride solution. Based on this technique, a new-type jet-flow pyrolysis reactor was designed, and then the fluid dynamics (pressure and velocity) inside the reactor was numerically simulated using a computational fluid dynamics method. The self-produced pressure (p) and the fuel inlet velocity (v) satisfied a quadratic function,p=0.06v2+0.23v−4.49. To fully utilize the combustion-generated heat in pyrolysis of rare earth chloride, an appropriate external pressure p=v2+3v−4.27 should be imposed at the feed inlet. The 1.25- and 1.5-fold increase of feed inlet diameter resulted in decline of adsorption dynamic pressure, but the intake of rare earth chloride increased by more than 30% and 60%, respectively. The fluid flow in the reactor was affected by the feeding rate; the fluid flow peaked near the throat of venturi and gradually smoothed down at the jet-flow reactor’s terminal along with the sharp decline of feeding rate.