論文題目：Numerical investigation on full thermodynamic venting process of liquid hydrogen in an on-orbit storage tank
期刊名稱：International Journal of Hydrogen Energy
影響因子：4.216（2019）
作者：Zhongqi Zuo, WenBing Jiang, Xujin Qin, Yonghua Huang*
發表年月：2020年8月-在線
中文摘要：液氫/液氧推進劑憑藉其比衝大的特點逐漸成為長距離空間飛行任務的首選組合。而液氫等低溫流體貯存溫度極低，即使使用高性能絕熱材料也不能完全消除流入貯箱的環境漏熱。熱力排氣技術可有效降低低溫燃料在軌貯存時因環境漏熱和微重力產生的排放損失。然而以往文獻中大多僅關注熱力排氣系統中單個部件或者單個過程中低溫流體的熱力狀態變化，而少有針對系統整體運行規律的詳細討論。因此，本文提出了針對在軌液氫貯箱熱力排氣全流程的三維有限體積法-集總參數法複合仿真模型，具備綜合預測在軌低溫燃料貯箱內節流、噴射和混合過程的能力。該模型對貯箱內部的流體和噴射混合機構運用有限體積法，貯箱外的循環管路、節流閥、排氣閥中的流動和換熱過程使用集總參數法,既保留了貯箱內複雜流動和傳熱的細節特徵，又大幅降低了全流程的計算複雜性和提升了計算速度。該模型獲得的自增壓計算結果與NASA液氫自增壓實驗數據吻合良好。通過對包含連續兩個「自增壓過程-降壓過程」周期的全流程仿真計算與分析，發現在軌工況下貯箱內液氫的溫度均勻度明顯優於地面工況。對應地，在軌工況下貯箱內的自增壓階段在整個排氣循環中的佔比顯著高於地面工況。也就意味著，在地面進行的熱力學排氣試驗理論上比在空間在軌條件下更加苛刻。
英文摘要：Liquid hydrogen has been identified as a promising propellant for long-duration space missions, benefiting from its high specific impulse when paired with liquid oxygen. A full procedural computational fluid dynamic model was proposed for the jetting, mixing, throttling, and venting processes of thermodynamic venting systems (TVS) for the purpose of reducing liquid hydrogen boil-off on orbit. In addition to the mixing and jetting components as well as the fluid domain inside the storage tank, the external fluid circulation loop and the throttling device were also coupled into the solver in the form of user-defined code, which enabled simulation of the continuous complete thermodynamic cycles. The evaporation/condensation intensity factors for the liquid-vapor phase change were confined in a smaller range than those used in other studies through theoretical analysis. To enhance the numerical stability, the well-known Lee model for liquid-vapor phase change was modified by introducing a smoothing function. Simulations with a variety of initial temperatures, mass flow-rates and vent ratios were conducted, which revealed that the condensation of superheated vapor contributes noticeably greater than the disturbance of the temperature stratification during the depressurization processes. Depressurization efficiency was introduced for evaluating the TVS performance during the jetting process. Significant performance enhancement was observed when the temperature difference between the liquid and the ullage before jetting was enlarged. The self-pressurization period was found lasting longer time under on-orbit condition than that on the ground, which is attributable to the floating of the bulk liquid and higher uniformity of the temperature distribution after the jetting process in the absence of gravity.
精彩圖文：
本文中研究的貯箱示意圖
模擬所採用的UDF流程圖
噴射過程中貯箱內物理場分布
全流程TVS運轉過程中貯箱內物理參數變化規律
項目資助：國家自然科學基金(51676118，51936006)
全文連接：
https://doi.org/10.1016/j.ijhydene.2020.07.099
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