Hydrodynamic conditions in pilot or industrial cultivation systems significantly affect the process of microalgae cultivation. It is necessary to ensure sufficient mixing and even distribution of the flowing medium in the entire irradiated area of the photobioreactor (PBR). It is also important to prevent the formation of dead zones in which sedimentation or uneven retention of microalgal cells could occur. In order to intensify the mixing of the processed medium and homogenizes the flow in the entire cross-section of the flat panel PBR chamber, the static mixer was designed. A numerical model of hydrodynamic conditions in PBR with static mixer was validated based on the experimental measurements. Validated model allows a detailed investigation of local hydrodynamic parameters in the PBR chamber. The designed static mixer significantly reduces the homogenization time of the processed medium in the PBR chamber. According to the results, installation of static mixer proved it is possible to eliminate the formation of dead zones.