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分析了液体模塑成型工艺(LCM)下织物预成型体中双尺度流动以及由此造成的空气裹入,进而产生细观及微观气泡的现象。基于多相流(VOF)方法建立了树脂空气两相流体在单胞内部流动的数学模型,并确定了该模型中多孔介质阻力源项和毛细力源项的具体形式。基于Fluent软件的UDF功能实现了上述两相流模型的数值求解,研究了平纹织物单胞中的两相流动以及2种气泡的生成过程。对Rovcloth 2454织物的气泡生成仿真结果显示,毛细数Ca对气泡的产生有决定性作用:当毛细数接近临界毛细数Cac时,气泡产生量最低,而当Ca小于Cac时,容易产生细观气泡,反之容易产生微观气泡。通过与文献中的理论预测和实验数据对比,验证了本文算法的正确性。
The double-scale flow in the fabric preform and the entrapped air caused by the liquid molding process (LCM) were analyzed. The mesoporous and microscopic bubbles were also observed. Based on the multiphase flow (VOF) method, a mathematical model of the flow of resin air two-phase fluid in the interior of the unit cell was established and the specific forms of the porous medium resistivity and capillary force source terms were determined. The UDF function based on Fluent software realizes the numerical solution of the above two-phase flow model, and studies the two-phase flow and the formation of two kinds of bubbles in the unit cell of plain weave fabric. The simulation results of bubble generation in Rovcloth 2454 fabric show that capillary Ca plays a decisive role in the generation of bubbles: when the capillary number is close to the critical capillary Cac, the bubble generation is the lowest, while when Ca is smaller than Cac, Conversely easy to produce micro-bubbles. By comparing with the theoretical prediction and experimental data in the literature, the correctness of the proposed algorithm is verified.