Numerical Simulation Of Radiation Transfer In Photobioreactor Of Energy Microalgae

Human are facing an unprecedented challenges of Energy shortage in the21st.Firstly,the continued population growth of the world’s and the emergence of aglobal economy are creating more stress on the resources of the earth. Secondly, theburning of traditional energy is becoming increasingly serious pollution of theenvironment. Therefore, the renewable and environmentally friendly biomass energyhas attracted more and more scholars concerned. Due to high oil field, fast growth, highenergy density, and the small use of field, the microalgae get more and more attentions.Although the use of microalgae biomass energy development prospects, there are manydifficulties of technique to be solved.Currently, the bottleneck in industrial development of energy microalgae is how toimprove the performance of the photobioreactor to reduce the cost of cultivation and tomake cultivation in large scale. To optimize the light environment of cell is the keyfactor to increase the efficiency of the photobioreactor. To analysis the Microalgaegrowth on the local light environment relies on the analysis of the process of theunsteady convection coupled with radiation within the bioreactor.This article is based on the means of computational fluid dynamics to discuss themulti-dimensional and multi-spectra light transport of the microalgae in thephotobioreactor and the process of the radiation transport coupled unsteady convection，and then analysis the unsteady convection process of the algal cells on the local lightenvironment. The microalgae selected chlorella，because it’s Radiation characteristicparameters are well studied. Considering Flat-plate photobioreactor simple structure,high area ratio of light, and the small use of field，so this paper uses a new type offlat-plate photobioreactor which has a multilayer separators. This paper analysis theeffect of the microalgae radiation transport process in the photobioreactor underdifferent concentrations and different lighting conditions. Then the article discussed theflow characteristics in the photobioreactor under different Aeration rate. Microalgaevarying optical properties and the “flashing light effect”caused by the unsteadyconvection coupled with radiation are discussed. By means of numerical simulation theauthor found that the frequency of light and dark will increase with the concentration ofmicroalgae and the aeration rate from0.003Hz to0.02Hz. The microalgae cells willabsorbed more radiation energy when irradiated with red or blue. So，it should try tochoose the band440nm or680nm light source Irradiate algal cells.