关于混合气体输运系数计算方案的影响研究  

A study on the influence of calculation scheme for transport coefficients in gas mixtures

作　　者：王晓栋[1] 卢德勇 WANG Xiaodong;LU Deyong(Computational Aerodynamics Institute of China Aerodynamics Research and Development Center,Mianyang 621000,China)

机构地区：[1]中国空气动力研究与发展中心计算空气动力研究所

出　　处：《空气动力学学报》2019年第5期819-826,共8页Acta Aerodynamica Sinica

摘　　要：为了研究混合气体分子输运系数的不同近似计算方案对边界层及射流剪切层流场计算的影响,以含双方程k-ωSST湍流模式的质量平均Navier-Stokes方程为控制方程,分别采用两种计算方案:公式计算混合气体导热系数、扩散系数的直接计算方案和由普朗特数和施密特数等关联混合气体导热系数、扩散系数的关联计算方案,对Burrow和Kurkov实验流场进行了数值模拟。结果表明:与采用直接计算方案相比,采用关联计算方案,流场数值模拟在获得相当的计算结果的同时,大大降低了计算量;抛开与控制方程的相容性问题,混合气体扩散系数各直接计算方案对流场参数计算影响不明显;在湍流计算时,边界层/剪切层区域的混合气体湍流输运系数大于分子输运系数,由此弱化了混合气体分子输运系数不同的近似计算方案对流场数值模拟的影响;相对输运系数近似计算方案,湍流可压缩修正模型对组分剖面的影响更为明显。计算表明,在边界层近壁流场、剪切层流场以及层流流场的精细化数值模拟中,混合气体分子输运系数的计算方案有重要的影响。In order to investigate the influence of approximate computation scheme for transport coefficients in gas mixtures on the numerical simulation of the flow field of scramjet combustor,the cold flow field with multicomponent gas mixtures in Burrows-Kurkov combustor has been simulated numerically by using the Favre-Averaged Navier-Stokes equations with the two-equation k-ω SST turbulence model. The effects of approximate computation scheme are studied for transport coefficients in gas mixtures on the numerical simulation with boundary layer and shear layer. The result indicates that: 1) by comparing with direct computation scheme thermal conductivity coefficients and diffusion coefficients in gas mixtures calculated directly by approximate formula,the correlated calculation scheme,with those obtained by an algebraic formula consisting of Prandtl/Schmidt number and viscosity coefficient of the gas mixtures can produce comparative results and rapidly reduce the computation cost;2) without the consideration of the consistence with the governing equation,the effect of computation schemes for diffusion coefficients in gas mixtures is insignificant;3) in the numerical simulation of turbulent flow field,the turbulent transport coefficients in the boundary layer and shear layer are much greater than the molecular transport coefficients in gas mixtures,and the effect of different computation schemes for the molecular transport coefficients in gas mixtures is weakened consequently;4) comparing with the computation schemes for the molecular transport coefficients in gas mixtures,the compressible correction terms to Menter’s two-equation turbulence models have greater effect on the composition profiles. The results also show that the approximate computation scheme for transport coefficients in gas mixtures plays an important role in the precisely numerical simulation for the boundary-layer flow fields near surface,shear-layer flow fields,and laminar flow fields with multicomponent gas mixtures.

关 键 词：超声速流动 壁面射流 输运系数 氢燃料 数值模拟 

分 类 号：V211.3[航空宇航科学与技术—航空宇航推进理论与工程]