本研究針對兩相流流場對衝擊壁面之機械能沖蝕進行評估分析，使用Oka沖蝕物理模型計算三氧化二鋁(Al2O3)粒子對於衝擊壁面之累加沖蝕，初步假設在衝擊壁面上的熱邊界條件是固定壁溫，其衝擊壁面材料為石墨。由於影響沖蝕之因素眾多，分別針對Oka模型所需要之Oka參數、粒徑效應以及壁面退縮外型進行分析，其中觀察到Oka參數之參考沖蝕率(eref)為影響沖蝕大小之重要參數，並與實際實驗退縮量進行比對，整體之形狀趨勢以及沖蝕厚度峰值皆與實驗結果相符，唯有沖蝕位置分佈仍有差異；接著，在粒徑效應中，粒子大小也為影響沖蝕行為主要變數之一，故考慮合適之粒子大小相當重要以及貼近於實際狀況之粒徑分佈，將能有效的預估其沖蝕厚度；除上述參數以外，在衝擊壁面上，不同表面輪廓外型對於衝擊壁面的流場及熱負荷存在著很大的影響，進而改變粒子之沖蝕行為，故本研究嘗試加入動網格退縮探討其作用。
由於Fluent內建之Oka沖蝕模型無法將其計算之沖蝕率進行動網格，因此本研究欲開發機械能沖蝕(mechanical erosion)外掛程式與動網格搭配；且為更有效評估衝擊擋板的升溫現象，本研究利用氣動力數值模擬計算固態火箭發動機噴焰熱流場之熱負荷，嘗試耦合熱防護材料之燒蝕邊界條件，將初始衝擊壁面上之熱邊界條件改為二維熱傳之燒蝕模型，假設衝擊壁面之熱通量沿擋板徑向與厚度方向熱傳，研究結果發現以石墨為壁面材料時，預估其壁面溫度無法到達燒蝕條件，因而只考慮機械能沖蝕對於石墨擋板之磨耗。

Previous literatures show that the thermal loading effects of particles on the impinge surface is very significant, which is caused by the heat transfer of high temperature particles impinging on the surface. First of all, two-phase flow numerical simulation coupled with Oka model is used to simulate the mechanical erosion process of supersonic jet impinging on thermal protection material (TPM) in this study. The boundary condition on the impinge surface is initially assumed as the isothermal wall condition, and the erosion depth of impinging surface is calculated by considering the actual solid-propellant rocket alumina particles (about 16% of the plume) in the present computational fluid dynamics (CFD) model. Since there are many factors that affect erosion, this study investigates the sensitivity of Oka parameters, particle sizes, and wall surface profiles due to the particle impingement. Numerical results show that reference erosion rate (eref) is the main parameter that determines the magnitude of the erosion depth and 0.000154 is the appropriate value for this study. Moreover, when selecting particle sizes, this study recommends to reduce the particle diameter and to assume the maximum particle size as 5μm. The discussion for different wall surface profiles, the flat surface has deeper erosion thickness compare to the concave surface. Furthermore, this study also develops dynamic mesh user defined function (UDF) incorporating two-dimensional (2D) transient heat conduction model with Oka mechanical erosion model in the current simulation to evaluate the surface evolution process effects.

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