本研究使用計算流體力學方法，建立超臨界流體微細發泡射出成形氣泡成長之數值模型，並利用不同製程參數條件進行超臨界流體微細發泡射出成形之氣泡成長模擬分析，以了解在超臨界流體微細發泡射出成形中各參數對氣泡尺寸大小之影響。本研究使用連續、動量及能量方程式描述模穴內的流場，並利用波前方程式得知塑料在模穴內波前位置，以及使用氣泡成長方程式獲得氣泡尺寸大小。本文使用有限體積法離散流場統御方程式，並以流體體積法計算熔膠之波前分佈，同時以Cross-WLF黏度修正模型來描述熔膠在充填過程的非牛頓流體流變特性，氣泡成長方程式使用Amon和Denson提出的氣泡模型描述氣泡成長過程。由本研究所建立的數值模型與相關實驗結果比較，具有定性與定量上的一致性。研究結果顯示氣泡大小隨著持壓時間增加而減小，隨著反壓壓力降低而升高，隨著超臨界流體含量越高而減小，當量測點越接近壁面時，氣泡大小越小。反壓壓力為150 bar時，低持壓時間(tp < 5 s)時，計算結果與實驗結果有較高的一致性，此時在實驗參數點氣泡大小約為25 μm。

This study proposes a numerical model to simulate the bubble growth in the microcellular injection molding process assisted with counter pressure filling of gas, where various conditions is employed to investigate the effects of processing parameters on the bubble size. The microcellular injection molding process is described by the continuity equation, the momentum equation, the energy equation, and the front transport equation. The govern equations are discretized by a finite volume approach, while the volume-of-fluid method is employed to calculate the location of melt front. The non-Newtonian rheological behavior of polymer is described by the modified Cross-WLF model. The proposed numerical model is proven to give both qualitative and quantitative agreement with corresponding experiments. The results of this study reveal that the size of bubble decreases with the holding time and the weight percent of supercritical fluid, as well as the counter pressure. The size of bubble grows as the location of bubble moves away from the mold surface. Better agreement between numerical simulations and experimental results is found for the case with counter pressure of 150 bar, where the bubble size is about 25 μm at the reference point in the experiment

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