水射流切削技术是一种高能量密度的“冷”加工手段，近年来在特种制造领域有较快的发展，同时在生命科学及生物制造领域也显现出独有的特色。为更好地适应宿主生理环境，生物骨切削所需的磨粒必须具有良好的生物相容性，且不在骨组织间隙残留，氯化钠晶粒射流安全可靠、便于获得，成为首选。氯化钠晶粒射流既能够实现骨材料快速去除，又可以有效防止骨细胞热坏死，避免产生骨组织微裂纹，该技术虽尚未实现临床应用，但已成为医学界所关注的热点技术之一。氯化钠晶粒射流切削生物骨材料的特殊性在于，射流束中离散相磨粒粒径约在 100μm 以下，小于骨单元尺度（100-500μm），材料的去除是由磨粒对骨单元的次级结构直接切削破坏而实现的。研究离散相晶粒在附骨边壁约束流场中的动力学行为规律及其高速切削骨组织的作用机理，是实现生物骨安全高效切削的关键。本项目针对氯化钠晶粒射流与生物骨组织亚层级结构的相互作用关系展开研究，通过理论分析计算和可视化实验研究明晰切削加工域内射流束及离散相晶粒的运动状态，获得氯化钠晶粒射流在附骨边壁约束条件下的流动特征及结构演变规律，阐明离散相氯化钠晶粒在湍动流场激励下的行为规律并构建其动力学模型；基于生物骨层级结构理论建立胶原蛋白纤维束构成的骨组织亚层级结构模型，探明韧性纤维束在氯化钠晶粒作用下的切削断裂机制，进而揭示氯化钠晶粒切削生物骨材料的微观去除机理；分析骨组织切削表面微观形貌特征，揭示生物骨材料加工表面微观成形机制。本项目研究成果可丰富液固两相射流切削的理论体系，为水射流技术在骨切削领域的应用提供理论依据和技术基础，进而促进水射流技术在生物医学领域的应用发展，发挥其在骨切削方面的独特优势。

Water jet machining technology is a kind of cold processing method with high energy density. In recent years, it has a rapid development in the field of non-traditional manufacturing and shows its unique characteristics in the field of life sciences and biomanufacturing. In order to better adapt to the host physiological environment, the abrasive particles needed for bio-bone machining must have good biocompatibility and do not have residue in bone tissues. Sodium chloride abrasive grain is safe, reliable and easy to obtain, so it becomes the first choice. Thermal necrosis of bone cells and microcracks in bone tissue can be avoided by using the sodium chloride abrasive water jet (NaCl-AWJ) in natural bone machining. This technology has become one of hotspots in the medical field, although it has not been applied clinically. It is the key to realize safe and efficient machining of bone that studying the dynamic behavior of discrete phase sodium chloride grains in the confined flow field and the mechanism of high-speed cutting of bone tissue by NaCl-AWJ. Focusing on the interaction between NaCl-AWJ and sub-hierarchical structure of biological bone tissue at micro-scale, this scientific research will be carried out by combining theoretical analysis, numerical simulation and experimentation. (1) Achieve the flow characteristics and the variation of the NaCl-AWJ by throughly investigating the state motion of the jet within the cutting domain flow field. (2) Clarify the motion behavior of dispersed-phase particles under turbulent flow field excitation and construct its dynamics model. (3) Establish the sub-hierarchical structure model of the bone tissue based on the theory of hierarchical bone micro-structure and mechanical properties of fiber composites. (4) Explore the fracture mechanism of the collagen fiber bundles under the micro-cutting of sodium chloride grains. (5) Analyze the micro-morphological characteristics and micro-morphology distribution regularity of bone surface machined by NaCl-AWJ. Finaly, reveal the micro-removal mechanism of NaCl-AWJ machining natural bone and formation mechanism of surface micro structure. The research results will enrich the theory system of liquid-solid two-phase jet machining and provide the theoretical and technical basis for the application of water jet technology in the field of bio-engineering and natural bone machining.