Virtual tracer response methodology developed based on the trajectory data of the computer aided radioactive particle tracking (CARPT) technique was demonstrated. The demonstrated virtual tracer technique has advantages of non-invasiveness, near perfect injection/sampling, and flexibility in choosing the sampling/injection boundaries in a specific spatial pattern. With the developed virtual tracer technique, liquid and solids backmixing were investigated at the conditions mimicking Fischer-Tropsch synthesis. Experiments were conducted at different pressure, solids loading, and superficial gas velocity. The axial dispersion model (ADM) and recirculation and cross flow dispersion (RCFD) models were used to model the liquid mixing. Transient sedimentation dispersion model (SDM) was used to model the solids mixing. It was found that the measured axial dispersion coefficient (D_l) in the ADM model increases with increase in the pressure. The increase of dispersion coefficient was explained with the experimental values of mean axial diffusivity and mean recirculation velocity. Axial dispersion coefficients (D_z,uD_z,d) in the RCFD model (compartment model) were apparently lower than the D_l, due to the decoupling of global recirculation from the dispersion coefficients in the RCFD. Further, it was found that the dispersion coefficients in the RCFD model follow the trend of the axial eddy diffusivity with change in the operating conditions revealing the dominance of the turbulence in the upflow and downflow compartments. From the solids backmixing study, axial dispersion coefficient (D_s) of solids was found to increase with increase in the solids loading, pressure, and superficial gas velocity at the studied conditions.

中文翻译：

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使用基于放射性粒子跟踪 (RPT) 技术轨迹数据的虚拟示踪响应方法在气泡和浆液气泡柱中进行液相和固相回混

演示了基于计算机辅助放射性粒子跟踪 (CARPT) 技术的轨迹数据开发的虚拟示踪剂响应方法。所展示的虚拟示踪剂技术具有非侵入性、近乎完美的注入/采样以及在特定空间模式中选择采样/注入边界的灵活性等优点。通过开发的虚拟示踪技术，在模拟费托合成的条件下研究了液体和固体的回混。在不同的压力、固体负载和表观气体速度下进行实验。轴向扩散模型 (ADM) 和再循环和错流扩散 (RCFD) 模型用于模拟液体混合。瞬态沉降分散模型 (SDM) 用于模拟固体混合。D _l ) 在 ADM 模型中随着压力的增加而增加。弥散系数的增加用平均轴向扩散率和平均再循环速度的实验值来解释。RCFD模型（隔室模型）的轴向色散系数（D _{z , u} D _{z , d}）明显低于D _l，由于全球再循环与 RCFD 中的色散系数解耦。此外，发现 RCFD 模型中的扩散系数随着运行条件的变化而遵循轴向涡流扩散率的趋势，揭示了上流和下流隔室中湍流的主导地位。从固体回混研究中发现，在所研究的条件下，固体的轴向分散系数（D _s）随着固体负载、压力和表观气体速度的增加而增加。