The Flow Field Simulation And Structure Optimizaition Of Shaking Bioreactor

Biotechnology as one of the important driving force to lead the scientificdevelopment in the21st century plays an important role in fields of health care,environmental protection and chemical, and has greatly improved the our health andliving environment. Bioreactor is the key equipment to change biotechnology into theproduction practice. The shaking bioreactor as a new type of animal cell cultureequipment don’t need sterilization equipment which has the advantage of low shear force,high efficiency of dissolving oxygen, but when the big bioreactor filled with largequantity of fluid,both the cell density and metabolic products reduced. This paper is totrying to analyze the flow field and optimize the structure of shaking bioreactor with theCFD method.Firstly, this paper establish the CFD model of shaking bioreactor with the RNGk-εturbulence model, VOF liquid surface tracking method, and the moving boundary controlmethod which use dynamic meshing combined with UDF. Then we simulate the fluidmotion state in different types of shaking bioreactor filled with different liquid volumewith the method of CFD. And then we do experience with water on the shakingbioreactor. The result show that the simulation model agreed well with the actual, whichcan reflect the characteristics of the flow field.We research the oxygen transfer efficiency, shear rate size, shear rate distributionand the effects of mixing on the base of simulation results. The research shows that theshear rate, oxygen transfer efficiency and the mixing efficiency are all lower with theincrease of liquid volume which helps to reduce the damage to the cells, but which mayalso lead to the lack of oxygen, inadequate supply of nutrients and metabolic wasteexcretion poor in the large-scale cultivation.According to the existing problems of the current bioreactor, we optimize the shapeof its tanks, and make simulation experiment. The results show that the6.5L shakingbioreactor which added a spiral baffle liquid surface area has increased by55%thanbefore, the average volume of medium shear force increases slightly, but not obviousonly9.7%, and the turbulent kinetic energy increases from0.034to0.368which get alarge degree of improvement. All of those above make the6.5L bioreactor have betterdissolved oxygen performance and mixing characteristics also had significantimprovement. The50L shaking bioreactor with the square structure, liquid surface areais about4%lower than the original one, meanwhile the turbulent kinetic energydissipation rate has increased from0.034to0.368, shear rate distribution in low shearrate area percentage increase, but the high shear rate area is no more than before.