Jet clarifier combines jet hydrodynamics, flocculation and settling in a unit operation. Generally, Camp and Stein G t parameter is recommended to evaluate clarifier efficiency, where G stands for a global velocity gradient and t a characteristic time scale (contact time). In this work, a quasi-two-dimensional jet clarifier is developed to make easier the hydrodynamic analysis of the flocculation zone of a jet clarifier. Measurements of instantaneous velocity field are performed by means of particle image velocimetry (PIV). PIV data are processed to visualise the strong circulation induced by the jet in the flocculation zone. Characteristic time scales related to macromixing are then extracted. Based on PIV data processing, local and instantaneous shear rate are estimated. The analysis of space averaged velocity gradient G is presented. The range of G is 2 to 15 s⁻¹ whereas the residence time decreases from 4 to 1 hour. Based on the hydrodynamic analysis, the parameter Gt is shown to be constant around 30,000 for different jet flow rates. Efficiency of such jet clarifier can thus be foreseen.

射流澄清器在单元操作中结合了射流流体动力学、絮凝和沉降。通常，推荐使用 Camp 和 Stein G t参数来评估澄清池效率，其中G代表全局速度梯度，t一个特征时间尺度（接触时间）。在这项工作中，开发了一种准二维射流澄清器，以简化射流澄清器絮凝区的流体动力学分析。瞬时速度场的测量是通过粒子图像测速法 (PIV) 进行的。PIV 数据被处理以可视化由絮凝区中的射流引起的强循环。然后提取与宏混合相关的特征时间尺度。基于 PIV 数据处理，估计局部和瞬时剪切速率。提出了空间平均速度梯度G的分析。G的范围是2到15 s ^-1而停留时间从4小时减少到1小时。基于水动力分析，参数对于不同的射流流速，Gt显示为恒定在 30,000 左右。因此可以预见这种喷射澄清器的效率。