Deposition of solid particles exposed to the suction of dual pumps in the tank of a pumping station

CFD-based prediction of initial microalgal adhesion to solid surfaces using force balances

Adhesion of microalgal cells to photobioreactor walls reduces productivity resulting in significant economic losses. The physico-chemical surface properties and the fluid dynamics present in the photobioreactor during cultivation are relevant. However, to date, no multiphysical model has been able to predict biofouling formation in these systems. In this work, to model the microalgal adhesion, a Computational Fluid Dynamic simulation was performed using a Eulerian-Lagrangian particle-tracking model. The adhesion criterion was based on the balance of forces and moments included in the XDLVO model. A cell suspension of the marine microalga Nannochloropsis gaditana was fed into a commercial flow cell composed of poly-methyl-methacrylate coupons for validation. Overall, the simulated adhesion criterion qualitatively predicted the initial distribution of adhered cells on the coupons. In conclusion, the combined Computational Fluid Dynamics-Discrete Phase Model (CFD-DPM) approach can be used to overcome the challenge of predicting microalgal cell adhesion in photobioreactors.

Influence of the Installation Position of Submersible Pumps on Deposition Characteristics in Prefabricated Pumping Stations

Based on the discrete phase model (DPM), solid–liquid two-phase flow calculation, particle settling theory and MATLAB image processing technology, the influence of the installation position of submersible pumps on the deposition characteristics in a cylinder-type prefabricated pumping station was studied, and two performance indices, the deposition rate and area ratio of the easy deposition region were proposed. The results show that the area ratio and deposition rate of the easy deposition region increase as the suspension height increases. The discharge effect is best when the suspension height is 0.1H0, however, at this time the inlet bias of the pump is larger, which is not conducive to the smooth operation of submersible pumps. The area ratio and deposition rate of the easy deposition region gradually increase with the increase in the interval of the pumps. As the center distance increases, the area ratio and deposition rate of the easy deposition region basically decreases first and then increases, and reach the minimum at 0.1R and 0R, respectively.