This study was carried out to find the optimum clearance (impeller to bottom distance) for Rushton and pitch-blade turbine impellers in a stirred tank bioreactor for improved substrate mixing time added at interface, taking advantage of computational fluid dynamics. In this regard, the time needed for a thin layer of liquid, resembling substrate-rich or poor part, getting homogenously dispersed within the tank was calculated. The mixing time calculated in this way is called the surface aeration related mixing time (SARMT). SARMT was calculated using two approaches and was compared with each other. For the pitch-blade turbine impeller, a criterion which guarantees accurate mixing time by simulation was not satisfied, so the SARMT profile against clearance was not achieved. For the Rushton impeller, a general descending order of SARMT against impeller–bottom clearance was observed.

进行这项研究是为了找到搅拌罐生物反应器中 Rushton 和桨叶涡轮叶轮的最佳间隙（叶轮到底部距离），以利用计算流体动力学改进在界面处添加的底物混合时间。在这方面，计算了一层薄薄的液体（类似于富含基材或较差基材的部分）在罐内均匀分散所需的时间。以这种方式计算的混合时间称为表面曝气相关混合时间（SARMT）。使用两种方法计算 SARMT 并相互比较。对于桨叶涡轮叶轮，不满足通过模拟保证准确混合时间的标准，因此无法实现针对间隙的 SARMT 轮廓。对于拉什顿叶轮，