Abstract: The micro-pore structure of tissue engineering scaffold has a great influence on the flow of nutrient liquid and ingrowth of cell, it also directly affects whether the scaffold can replace the bone in the defect site, and continues to function. According to the SEM morphology of the internal structure in natural bone, three kinds of basic unit cells are designed. The flow property of nutrient solution in the scaffold is numerically simulated by using the finite element analysis software ADINA. The pressure and velocity distribution in different types of basic unit cells are obtained, and the influence of the model parameters on the average inlet pressure and velocity of nutrient solution is also analyzed. The results show that when nutrient solution flows from the upper face of the basic unit cells to the lower face, the maximum pressure appeared at the upper face and near the unit cell wall, the velocity increases first and then reduces, and the maximum velocity appears near the entrance. With the increase of pore diameter, the average inlet pressure decreases, the nutrient solution velocity increases, and its distribution becomes more uniform. As for hole plate-rod unit cell and hole plate unit cell, compared with connected aperture D, the effect of central aperture D_s on the average inlet pressure and flow velocity is small. By comparing the different types of basic unit cells, it is found that open rod unit cell shows a more stable and smaller average inlet pressure, its value is (0.300 to 0.412) Pa and the internal nutrient solution flows faster and more uniform, the maximum flow rate is (0.011 8 to 0.013 1) m/s. It is more beneficial to the growth of nutrient solution and cells. Results obtained in this study laid the foundation for the optimal design of the structure, research on profile modeling and rapid prototyping of bone scaffold.

Key words: basic unit cell, flow property, numerical simulation, tissue engineering scaffold