Evaluation of microalgal mortality in a centrifugal pump of a tubular photobioreactor

Industrially, the centrifugal pumps are very useful and within their applications, it can be found pumping fluids containing living microorganisms in suspension. However, this type of pumping can affect the growth of microorganisms because it generates high shear stresses, which are not supported by their cell walls, resulting in high cell mortality. In this article, we analyzed computationally a centrifugal pump used for pumping microalgal cultures in tubular photobioreactors. To do this, we modeled in CAD both the impeller and the volute; and then we conducted a simulation in CFX under the operation conditions of a photobioreactor. The evaluation of the velocity distribution and shear stresses inside the pump, led to conclude that it is impractical to use these pumping mechanisms, due to the high mortality rate that is expected for some microalgae species, such as the Chaetoceros muelleri; for which its viability can be reduced to levels of 52%".