Study Of Experiments And CFD Simulation Of Open Raceway Pond Photo-bioreactor For Energy Microalage

Open raceway pond photo-bioreactor for energy microalgae was systematic studied in this paper. The flow field test, CFD simulation, model validation, the internal structure optimization and optical characterization of algal cell were carried out.First of all, the flow structure in the small open raceway pond was investigated employing PIV. The results showed that adding inner and outer guiding baffles can reduce high turbulence kinetic energy dissipation rate region. The distribution of tubulence kinetic energy dissipation rate and turbulent kinetic energy are positively correlated.Then the flow characteristics in the small open raceway pond was simulated employing different turbulence models, and the results were compared with PIV results. The results showed that large eddy simulation can accurately capture the instantaneous characteristics and turbulent characteristics of flow field, but it has no obvious advantage in the time averaged velocity field. And the simulation results were verified by cultivation measurement.Optimization was carried out in the large raceway pond. The flow pattern is best when the inner and outer guiding baffle angles are 180 degree and extending lengthΔL/W is 0.5 considering average velocity,dead zone ratio and the power. The air inlet arrangement is best when the spacing along width directionΔY/W1 is 1/4 and the spacing along length directionΔX/L1 is 0.025 which average velocity magnitude along the light direction is increased by 4.36 times.Combining PTM with light attenuation model, particle motion trajectories are simulated with and without air. The result showed particles are in horizontal movement without air which has no exchange between light and dark areas. Different algae cell trajectories are regular with air which are in sine wave variation. After FFT light and dark frequency without air is approximately 0, while light and dark frequency is 0.2Hz with air.