Particle image velocimetry measurement of hydrodynamic properties of raceway pond with the effect of central wall

Raceway ponds with paddle wheel mixing are the most common choice for microalgae cultivation because they allow better interaction of algae cells with water, nutrients, and CO2. A central wall splits the algal pond into two channels, which significantly affects hydrodynamic properties of the pond. This study used the particle image velocimetry (PIV) technique to experimentally investigate the effects of the central-wall-end designs on the fluid properties of a laboratory-scale raceway pond. The rectangular and round ends of the central wall were compared using a velocity field, the Reynolds number, power consumption, and microeddy length. Flow circulation was found to be more effective in the round end model because of the smaller recirculation size and smaller dead zones. Mixing was improved by using a central wall with round ends. Power consumption was influenced by velocity, and the round-end model consumed less power during mixing. Higher turbulent mixing resulted in shorter microeddies that could damage the boundaries of the algae cells.