Pham L A, Laurent J, Bois P, Wanko A
ICube, UMR 7357, ENGEES, CNRS, Université de Strasbourg, 2 rue Boussingault, 67000 Strasbourg, France E-mail:
Water Sci Technol. 2018 Nov;78(8):1782-1791. doi: 10.2166/wst.2018.461.
Different combinations of operational parameters including water level, paddle rotational speed and influent flow rate were applied to investigate their impacts on mixing characteristics, residence time distribution and gas transfer rate in a pilot-scale high rate algal pond. In closed condition, the paddle rotational speed had a positive correlation with the Bodenstein number (Bo), water velocity and oxygen volumetric mass transfer coefficient (ka) while increasing water level generated a negative impact on these parameters, although the impact of water level on water linear velocity was small. The amplification effect of water level and paddle rotational speed on the sensitivity of Bo and ka should be noticed. Moreover, paddle rotational speed had more impact on ka than on Bo. The study in open condition indicated that effective volume fraction had a positive correlation with inlet flow rate and negative correlation with paddle rotation, while the opposite was observed in the case of Peclet number. The impact of water level variation on these parameters was unclear. Both water level and paddle rotational speed had negative impacts on the short-circuiting index, while no correlation was observed when varying inlet flow rate. In this study, the optimal operational conditions included low water level (0.1 m) and medium paddle rotational speed (11.6 rpm).
在中试规模的高速藻类池塘中，应用包括水位、桨叶转速和进水流量在内的不同操作参数组合，以研究它们对混合特性、停留时间分布和气体传输速率的影响。在封闭条件下，桨叶转速与博登斯坦数（Bo）、水流速度和氧体积传质系数（ka）呈正相关，而水位升高对这些参数产生负面影响，尽管水位对水的线速度影响较小。应注意水位和桨叶转速对Bo和ka灵敏度的放大作用。此外，桨叶转速对ka的影响比对Bo的影响更大。开放条件下的研究表明，有效体积分数与进水流量呈正相关，与桨叶旋转呈负相关，而在佩克莱数的情况下则观察到相反的情况。水位变化对这些参数的影响尚不清楚。水位和桨叶转速均对短路指数有负面影响，而改变进水流量时未观察到相关性。在本研究中，最佳操作条件包括低水位（0.1米）和中等桨叶转速（11.6转/分钟）。
