为了解小球藻在不同降雨强度下纵向沉降规律,在自制沉降柱中模拟降雨条件下小球藻纵向迁移,其实验结果如下:小球藻在表层聚集时,干扰深度随降雨强度增加而增大,干扰深度与降雨强度呈线性关系,且各降雨持续时间下的干扰深度变化较小,小球藻沉速随粒径减小、降雨强度减弱而变慢,沉速范围为34.7~194.3μm·s^-1,粒径较小的小球藻更容易受降雨的影响而增大其沉速;小球藻在纵向均匀分布时,干扰深度同样随降雨强度增加而增大,但干扰深度与降雨强度呈指数分布,同时干扰深度随降雨持续时间的延长而增加,沉速随降雨强度的增加而增大,沉速范围为16.7~27.0μm·s^-1;分析自然界降雨对小球藻干扰深度影响时,应按小球藻纵向均匀分布考虑,短时间降雨对湖库表层中小球藻的干扰深度影响甚小,长时间持续降雨对小球藻的干扰深度影响较大,在降雨时间相同时各降雨强度等级的干扰深度变化不大.
In order to understand the longitudinal settlement law of chlorella in different rainfall intensities, The vertical migration of chlorella is simulated in the selfmade setfling column under rainfall conditions. The experimental results are as follows.. When the chlorella at surface aggregation, interference depth increased with rainfall intensity and, interference depth and rainfall intensity were in linear relationship, the interference depth changed less in each rainfall duration, the chlorella settling velocity changed slower as particle size decreased and rainfall intensity receded, settling velocity range was 34.7-194.3 μm · s^-1 ,the smaller the particle size of chlorella, more susceptible to the impact of rainfall increasing its settling velocity. When the chlorella was at the vertical uniform distribution, interference depth increased with rainfall intensity, but the interference depth and rainfall intensity was of an exponential distribution. At the same time interfering depth increased as the rainfall duration lengthens, and the chlorella settling velocity increased with rainfall intensity. The settling velocity range was 16.7-27.0 /μm · s^-1. In analysis of the nature of rainfall influence on chlorella interference depth , we should consider chlorella vertical uniform distribution, and the rainfall exerted very small influence on the chlo- rella interference depth which was on the surface layer of the lakes and reservoirs in the short time. However the rainfall influence was very big in the long time and the interference depth in each rainfall intensity level changed little at the same rainfall time.