Study of the flow mixing in a novel open-channel raceway for algae production

Making fuel from algae is one of the promising approaches of producing biofuels. Open channel raceway is a typical facility of growing algae in medium and large scales. The algae growth rate in water raceway is affected by conditions of water temperature, nutrients, and sunlight. These conditions are essentially associated with the fluid mixing in the flow field. A good mixing of fluid allows better diffusion of nutrients and equal opportunities of exposure to the water surface and therefore sunlight, as well as a uniform temperature everywhere in water raceway so that all algae cells grow in the same rate. While a better fluid mixing is benefit to the growth of algae, it is also desirable that the energy needed to drive the flow and mixing being the minimum. In this work, a novel flow field has been proposed and the flow field was studied through flow visualization and CFD analysis. Optimization of the flow field for better flow mixing and low energy cost for the flow has been considered.