Assessment of Bhatnagar-Gross-Krook Approaches for Near Continuum Regime Nozzle Flows
Assessment of Bhatnagar-Gross-Krook Approaches for Near Continuum Regime Nozzle Flows
复制标题
近连续流态喷嘴流动的 Bhatnagar-Gross-Krook 方法的评估
DOI：
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
S. Gimelshein
中科院分区：
文献类型：
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作者：
Rakesh Kumar;E. Titov;D. Levin;N. Gimelshein;S. Gimelshein
由于存在多个流动长度尺度，对低至中等雷诺数喷嘴流膨胀至真空的精确和数值有效的建模可能是困难的。这种模拟对于预测推进推力和航天器污染都很重要，而这两者都很难在地面设施中测量。为此，采用直接模拟蒙特卡罗方法、具有速度滑移和温度跳跃边界条件的纳维尔-斯托克斯方程、求解Bhatnagar―Gross―Krook方程和椭球统计Bhatnagar ―Gross―Krook方程的统计和确定性方法，研究了雷诺数为1230和12,300时的锥形喷管流。Bhatnagar-Gross-Krook方程的确定性解和统计解与MonteCarlo直接模拟结果吻合较好。统计Bhatnagar―Gross―Krook方法和椭球统计Bhatnagar―Gross―Krook方法在连续和近连续区域中也比直接模拟Monte Carlo方法更有效，并且在稀薄流动部分（例如边界层和喷嘴唇缘周围的流动）中比Navier―Stokes方程更精确。
Accurate and numerically efficient modeling of low-to-moderate Reynolds number nozzle flow expansions to vacuum can be difficult due to the presence of multiple flow length scales. Such simulations are important for the prediction of propulsive thrust as well as spacecraft contamination, both of which can be difficult to measure in ground-based facilities. To that end, conical nozzle flows were studied for Reynolds numbers of 1230 and 12,300 using the direct simulation Monte Carlo method, Navier―Stokes with velocity slip and temperature jump boundary conditions, and statistical and deterministic approaches to the solution of the Bhatnagar―Gross―Krook and ellipsoidal-statistical Bhatnagar―Gross―Krook equations. The deterministic and statistical solutions of the Bhatnagar―Gross―Krook equation were found to be in good agreement with the benchmark direct simulation Monte Carlo results. Statistical Bhatnagar―Gross―Krook and ellipsoidal-statistical Bhatnagar―Gross―Krook methods were also found to be more efficient methods than direct simulation Monte Carlo in the continuum and near-continuum regime, and more accurate than the Navier―Stokes equations in the portions of the flow with rarefaction, such as the boundary layer and the flow around the nozzle lip.