探空八號火箭酬載任務為中山科學研究院開發之探空計畫，目的在於接續探六計劃所建構之科學酬載回收艙研發。而本文目的是以數值模擬探八回收艙在高速飛行下之流場與氣熱動力(aerothermodynamics)特性，並探討探六與探八回收艙因幾何外型效應對於氣熱動力的影響。模擬回收艙之高度為14,000 m~36,600 m；馬赫數介於0.5至6；紐森數(Knudsen number, Kn)皆小於0.01。本文採用FLUENT套裝軟體為分析工具，先針對國外的MESUR太空艙、圓球狀太空艙與探六回收艙進行模擬，以驗證本文數值模式。 經由驗證證明本文之數值模式對於流場與氣熱動力模擬有一定的精確度。由模擬結果顯示，回收艙外型由探六等比例地放大為探八，阻力係數將會增大，可使回收艙有效地減速；當探八達到馬赫數4、攻角為180度時，在停滯點有最大之壓力35.32 kPa；當馬赫數為6、攻角為180度時，表面溫度最高會達到約2700 K，且在靠近肩部位置有最大熱傳率值5 kW/m2。對於回收艙表面的壓力、溫度與熱傳率，外型改變影響則不大。而本文之模擬結果將可作為探八回收艙結構強度與防熱設計上的參考依據。 Sounding Rocket VIII Mission (SR 8) is a sounding plan developed by Chong-Shan Institute of Science and Technology, the object is to continue the development of Sounding Rocket VI Mission (SR 6). The purpose of this paper is to analyze the flow field and characteristic of aerothermodynamics of the reentry capsule of SR 8, and discuss geometrical effects between SR 8 and SR 6. The range of height in simulation is 14,000~36,600 m, Mach numbers are from 0.5 to 6, and Knudsen numbers all less than 0.01. The FLUENT software is to be the analysis tool. To verify the numerical model, this work will simulate MESUR capsule, spherical capsule and capsule for SR 6. Through a series of verification and comparison, the accuracy of numerical model in this work has been established. Simulation predicts that the drag coefficient increase when shape of capsule for SR 6 enlarge proportionally to SR 8. As SR8 reaches to Mach number 4 and attack angle is 180o, there is maximum pressure of 35.32 kPa occurs at the stagnation point; When Mach number further increases to 6 at attack angle of 180o, surface temperature increases upto 2,700 K, in addition the heat transfer rate appears near the shoulder region with a value of 5 kW/m2. The geometry effect is mild on the surface pressure, surface temperature and heat transfer rate of the reentry capsule. The present simulation results can provide a valuable design guide on the structural strength and thermal protection of SR8 reentry capsule.
