注射条件对LCM工艺非饱和流动特性影响

双尺度多孔纤维预制体填充过程中延迟浸润的非饱和流动现象，对基于树脂流过区域为完全饱和区域的充模理论及模拟方法提出了挑战。通过控制体/有限单元（CV/FE）法结合沉浸函数实现了液体模塑成型工艺（LCM）中非饱和填充浸润的数值模拟，并对比了恒压下的实验结果，验证了其可靠性。分析讨论了注射口压力、流量和液体黏度对双尺度多孔纤维织物非饱和填充浸润特性的影响。结果表明:在允许误差内，该数值模拟结果可靠，可用于分析讨论各因素对双尺度多孔织物非饱和流动特性的影响；填充浸润过程中，纤维织物内部非饱和区域长度并非保持不变，而是随着填充浸润的进行经历了4个变化过程；不同注射条件下，压力、流量及黏度对非饱和流动特性影响不同。研究结果对合理控制注射条件及流体特性实现双尺度多孔纤维预制件的完全浸润具有指导意义。 

Influences of injection conditions on unsaturated flow characteristic of LCM process

The delayed impregnation of dual-scale porous fiber preform during unsaturated flow process presents a challenge for the molding theory and simulation method which based on the assumption that the region nearing the flow front was completely filled and the flow was saturated during the filling process. Combined with sink function, the numerical simulation of unsaturated filling and infiltration for liquid composites molding (LCM) was realized by control volume/finite element (CV/FE) method, and the validity of the results was proven by the comparison of experimental results under the constant pressure, and the influences of injection pressure, flow rate and fluid viscosity on the unsaturated filling and infiltration characteristics of dual-scale porous fabric were also discussed. The results show that the numerical results are reliable and can be used to analyze different factors' impact on unsaturated flow characteristics of dual-scale porous fiber preform within permissible error; and the length of unsaturated region isn't constant during the whole filling process in fiber fabric which experiences four stages; pressure, flow rate and viscosity have different influence on unsaturated flow characteristic; the research results have guiding significance on appropriate manipulated injection conditions and fluid characteristic to realize the fully impregnation of dual-scale porous fiber preform.