基于多组分非牛顿流体模型的血流特性模拟

Simulation of blood flow characteristics based on a multicomponent non-Newtonian fluid model

  • 摘要: 可视化人体内血液流动特性对精准诊断心血管疾病、解析病理机制及优化治疗方案至关重要. 然而,传统医疗手段难以直接观测血液流动状态,且对血液成分耦合效应的量化评估不足. 为此,本文提出一种基于多组分非牛顿流体模型的血流特性模拟方法. 首先,基于Walburn–Schneck模型描述非牛顿流体表观黏度;其次,通过引入体积分数,将Walburn–Schneck黏度模型拓展至多组分应用场景,准确模拟了不同组分间的交互作用机制,实现了多组分非牛顿流体延展和流动效果的准确模拟;最后,构建血管壁处固–液作用力模型,采用改进的光滑粒子流体动力学方法对壁面剪应力和黏附力进行建模,修正了壁面附近粒子截断对流固边界附近流体模拟的计算误差. 实验结果表明,本文方法可有效捕捉非牛顿流体剪切速率的依赖特性及多组分流体的混合扩散行为,较传统模型能更真实地还原复杂血管结构中的血液流动状态. 研究成果为数智化诊疗提供了新的技术路径,有望辅助深化理解血流动力学异常相关的病理机制.

     

    Abstract: Visualizing characteristics of blood flow in the human body is essential for accurate diagnosis of cardiovascular diseases, analysis of pathological mechanisms, and optimization of personalized treatment. However, traditional medical methods, relying primarily on imaging observations and empirical analysis, face significant limitations in directly observing blood flow states and lack sufficient quantitative assessment of the coupled effects of blood components. Therefore, in this study, we propose a blood flow characteristics simulation method based on a multicomponent non-Newtonian fluid model, integrating rheological modeling, multiphase coupling, and fluid–solid interaction mechanisms to address these problems. The proposed method takes three pivotal advancements into consideration. First, the Walburn–Schneck model is employed to describe the shear-thinning behavior of non-Newtonian fluids, wherein the viscosity is characterized as a function of shear rate. Second, the Walburn–Schneck model is extended to multicomponent application scenarios by introducing volume fractions, enabling the modeling of interaction mechanisms between different components and their collective influence on bulk viscosity. This extension allows for accurate simulation of multicomponent non-Newtonian fluid dynamics, including the complex deformation and flow patterns that traditional single-component models struggle to capture. Third, a solid–liquid interaction force model at the blood vessel wall is constructed using an improved smoothed particle hydrodynamics framework. The model incorporates wall shear stress and adhesive forces, effectively mitigating computational inaccuracies near the fluid-solid boundary caused by particle truncation. As a result, the model achieves robust simulations in complex vascular geometries. To verify the effectiveness of the proposed method for blood flow simulation, a series of experiments were performed. The drop and deformation experiments of non-Newtonian fluids were first conducted. The results demonstrated that the Walburn–Schneck model can accurately capture the shear rate-dependent viscosity changes, outperforming the Carreau model in reproducing fluid extension and thinning effects. To further assess the model’s adaptability to high-viscosity fluids, experiments on the coiling and folding phenomena exhibited by non-Newtonian fluids with high-viscosity characteristics were also carried out. The extended Walburn–Schneck model effectively captured and maintained the complex crease effects generated by fluid curling and folding, thereby verifying the model’s accuracy and applicability in high-viscosity scenarios. Then, simulations of multicomponent non-Newtonian fluids with varying volume fractions of high-viscosity components were carried out, and the stability of the multicomponent non-Newtonian fluid model was verified through the three-phase dam break experiment. Finally, simulations across diverse vascular scenarios were conducted to verify the efficacy of the solid-liquid interaction force model and the multicomponent non-Newtonian fluid model in the blood flow scenario. The model effectively reproduced mixing-diffusion behaviors in complex vascular structures, including straight, bifurcated, and stenotic vessels. Stable fluid–solid coupling and no particle penetration were observed, highlighting the robustness and accuracy of the proposed method. The research results provide a new technical pathway for digital and intelligent medical diagnosis, holding promise to assist in deepening the understanding of pathological mechanisms related to hemodynamic abnormalities. By integrating the fluid viscosity of the multicomponent with non-Newtonian rheology, the method improves the accuracy of hemodynamic simulations. Future work will focus on integrating microscale cellular interactions and dynamic vascular elasticity to further bridge the gap between simulation and clinical reality.

     

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