Large eddy simulations of the turbulent flow in a stirred reactor
Large eddy simulations of the turbulent flow in a stirred reactor
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DOI：
10.1016/s0009-2509(98)00203-6
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发表时间：
1998-12
影响因子：
4.7
通讯作者：
J. Revstedt;L. Fuchs;C. Trägårdh
中科院分区：
文献类型：
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作者：
J. Revstedt;L. Fuchs;C. Trägårdh
对单级Rushton涡轮机搅拌的折流板反应器进行了大涡模拟。涡轮机位于反应器的中间高度。数值求解了非定常空间滤波不可压Navier-Stokes方程。这些大涡模拟（LES）提供了用所谓的雷诺平均方程和相应的模型不能获得的流场的细节。未解决的尺度已通过离散化的截断误差隐式建模。叶片的运动被描述为与时间相关的动量源。研究了时均流动特性，即平均流动和湍流。相位平均用于表征相对于叶轮叶片的流动。功率谱密度和相关性，在时间和空间进行了研究。结果已与实验数据从几个来源，也与其他模拟的数据进行了比较。将我们的数据与测量结果进行比较，我们看到定性和定量的总体一致性良好。在叶轮流中，由于尾涡对，我们观察到径向方向上的流动加速。这个加速度也可以从已发表的实验和数值数据中推导出来。然而，在叶轮区域的速度波动方面存在一些差异。这些差异可能是由于叶轮描述不准确造成的。
Large eddy simulations of a baffled reactor stirred with a single Rushton turbine were performed. The turbine was positioned at mid-height in the reactor. The unsteady spatially filtered incompressible Navier–Stokes equations have been solved numerically. These large eddy simulations (LES) provide details of the flow field that cannot be obtained with the so-called Reynolds averaged equations and corresponding models. The un-resolved scales have been modelled implicitly through the truncation errors of the discretisation. The motion of the blades was described as time-dependent momentum sources. The time-averaged flow properties, mean flow and turbulence, have been studied. Phase averaging was used to characterize the flow relative to the impeller blades. Power spectral density and correlations, both in time and space were investigated. The results have been compared with the experimental data from several sources and also with the data from other simulations. Comparing our data with measurements we see an overall good agreement both qualitatively and quantitatively. In the impeller stream we observe an acceleration of the flow in the radial direction due to the trailing vortex pair. This acceleration can also be deduced from published experimental and numerical data. There are however some discrepancies concerning velocity fluctuations in the impeller area. These discrepancies are probably caused by inaccuracy in the impeller description.