Abstract: A hydrodynamic model for the U-valve was proposed based on the Newton's second law to predict solid flow rate under the fluidization discharging mode. During steady discharging, the particles descended in the moving-bed mode in the standpipe, while the particles moved upwards in the fluidization mode in the discharging chamber. A circulating fluidized bed with a U-valve was established and operated to study the performance of the U-valve using silica sand with average diameter of 81.9 mm. Experiments revealed that the solid flow rate increased linearly with the increase of superficial gas velocity. The simulated pressure drop and solid flow rate were in good agreement with those experimental data, e.g. the deviation was ±2% for pressure drop across the discharging chamber, and ±7% for the solid flow rate, demonstrating the validity of proposed algebraic model. Key words: U-valve; discharge under fluidization mode; hydrodynamic modeling; solid

Key words: U-valve, discharge under fluidization mode, hydrodynamic modeling, solid flow rate

摘要： 针对U型阀在常温常压下的流态化排料状态，建立了以力平衡为基础的数学模型，用于计算该状态下的排料速率，并在循环流化床系统中用平均粒径为81.9 mm的石英砂颗粒进行流态化排料实验，对数学模型进行验证. 结果表明，排料室表观气速为1.5~2.5Umf(Umf为最小流化速率)时，排料速率随排料室表观气速增大而增大，U阀处于流态化排料状态. 不同条件下用模型对排料室压降和排料速率进行计算，与实验数据的平均计算误差排料室压降为±2%，排料速率为±7%，计算值和实验值吻合较好.

关键词: U阀, 流态化排料, 数学模型, 排料速率