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Please use this identifier to cite or link to this item: http://ntour.ntou.edu.tw:8080/ir/handle/987654321/10121

Title: 連續流與稀薄氣流一體化數值計算法研究
Unified Computational Methods for Continuum and Rarefied Flow
Authors: 黃俊誠
Contributors: NTOU:Department of Merchant Marine
國立臺灣海洋大學:商船學系
Keywords: 稀薄氣體動力學;Boltzmann 方程式;Navier-Stokes 方程式;Knudsen 數;分立座標法;守恆律高解析算則;WENO 算則;平行計算;動態負載平衡;Gauss-Hermite 積分法;連續體流域;過渡流域;運載火箭;戰術導引飛彈;PPCVD
Rarefied gas dynamics;Boltzmann equation;Discrete ordinate method;High resolutionconservative scheme;WENO scheme;MPI parallel computing;Dynamic load balance,Gauss-Hermite quadrature;Continuum flow regime;Transitional flow regime;PPCVD
Date: 2008-08
Issue Date: 2011-06-28T07:28:17Z
Abstract: 摘要:穿越大氣層之飛行環境跨越連續體流域(continuum flow regime)與稀薄氣體流域,傳統 上高空飛行器氣動力學設計分析程序是針對各氣體流域的需求;分別採用適當的方法。在連 續體流域,以計算流體力學(CFD)技術解Navier-Stokes 方程式獲得飛行器表面壓力、溫度、 周圍流場結構與氣動力性能係數等相關資料。在Knudsen 數較大的稀薄氣體流域,普遍應用 DSMC 法計算稀薄氣體氣動力特性。但是對於Knudsen 數較低的近連續體流域,Navier-Stokes 方程式解不夠準確,而DSMC 法計算量相當高,無法普遍應用。有必要發展一體化的數值計 算技術,提高近連續體流模擬效率,使氣動力分析結果更精確。 因此,本計畫目標是應用分立座標法結合CFD 相關技術,發展三維Boltzmann 模型方程 式數值計算技術,應用於運載火箭、探空火箭、再入戰術導彈等之稀薄氣體動力學分析。同 時本計畫也將結合Navier-Stokes 與Boltzmann 方程式的計算法,建立一體化(unified)連續 體流與稀薄流模擬技術,提高近連續體流氣動力學計算效率與精度。 本研究計畫期間共計三年。分年目標簡述如下: (1)第一年主要以建立三維Boltzmann 模型方程式數值計算程式為目標。重點工作項目包括 發展自調適分立座標法、建立尺度因子Gauss-Hermite 積分法、建立三階與四階準確度 WENO 計算程式、應用空間分割法建立平行計算程序等。數值方法完成測試驗證後,將 應用於單錐體與雙錐體載具稀薄流場模擬,並探討稀薄氣體效應氣動力性能。 (2)第二年以建立連續體流與稀薄流一體化計算技術為主要目標。重點工作項目包括發展三 維數值計算程式平行運算功能、結合Navier-Stokes 方程式與Boltzmann 模型方程式數值 計算程序、發展巨觀與微觀通量耦合計算算則、建立局部流場稀薄度判別基準公式等。 同時也探討高空噴流(姿態控制噴嘴冷噴流與發動機尾焰)流場與氣動力學,以及壓力 脈衝化學氣相沉積反應腔負載氣體暫態流場特性等相關問題。 (3)第三年以建立動態負載平衡平行運算技術,提高運算效率,並應用於極超音速高空飛行 器稀薄氣動力學分析為主要目標。重點工作項目包括測試流場稀薄度判別法適用性、發 展計算域分割技術、以運載火箭與戰術導彈為例,分析稀薄氣動力學特性等。 預期本計畫完成後將充分建立近連續體流至過渡流域模擬,與低次音速至極超音速稀薄 氣動力學分析的技術能量。配合國內DSMC 法的發展與應用,使稀薄氣體動力學的研究更為 完備。本項新開發技術除了應用於飛行器氣動力學研究外,也可以推廣應用於衛星姿態控制 噴嘴、真空泵浦、化學氣相沉積、以及微機電系統等科學及工業上。在太空計畫、國防科技 與產業發展等均能有所助益。 第一年研究計畫已奉核定於95 年度執行,期限95.08.01 至96.07.31。現申請第二、三年 後續研究計畫。
Abstract:The flight enviorments of the tran-atmosphere vehicles include the continuum flow regime and rarefied flow regime. The disciplines of studies are gas dynamics and kinetic theory. In traditionally, the methods for aerodynamic design of high speed space vehicles are depend on the flow regime considered. On Continuum flow regime, the CFD method based on the solution of Navier Stokes equations is used to obtain surface pressure, temperature, the flow structure around vehicle, and the coefficients of aerodynamic characteristic. For rarefied gas flow regime, which has larger Knudsen number, DSMC method has been widly used. However, for the nearly continuum flow regime, the solution of Navier Stokes equation does not obtain accurate results and the DSMC method can not be widely used since the computing time is too long. It is necessary to develop an unified numerical method for simulation of rarefied, transition, and continuum flow and used for aerodynamic design of space vehicle, especially in nearly continuum flow regime. Therefore, one of the purposes of this project is to develop a numerical solver for 3 dimensional model Boltzmann equation by integrating descrete ordinate method and CFD method. Another purpose is to develop efficient and accurate computational algorithms for unified simulations of rarefied and continuum flow regimes by combining the methods for Navier Stokes and Boltzmann equation.. The period for this project is three years. The special items of proposed research for each year are listed as follows: (1)The purpose of first year is to develop a numerical solver for 3 dimensional model blotzmann equation. The adaptive discrete ordinate method, scale factor Gauss-Hermite quadrature, 3rd and 4th order accurate WENO schemes, and parallel computing algorithm are completed. All the new methods will be calibrated and validated with some standard test cases, like as rarefied flow in cylinder, sphere, cone, and double cone, which are the basic configuration of space vechicle. (2)The purpose of 2nd year is to establish a unified solver for continuum and rarefied flow. The working items are to develop parallel computing code, coupling flux algorithm, domain switching criteria, and to combine the Navier Stokes and model Boltzmann solver. The unified solver will be used to study the nozzle flow of altitude control system of sattlite. Also the unsteady flow in reactor of PP-CVD will be simulated and studied. (3)The purpose of 3rd year is to develop the parallel code of the unified solver by dynamic load balancing technique. The aerodynamic performance of launch vehicle and ballistic missile will be studied.
Relation: NSC96-2221-E019-067-MY2
URI: http://ntour.ntou.edu.tw/ir/handle/987654321/10121
Appears in Collections:[商船學系] 研究計畫

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