壁温比对圆截面隔离段激波串的影响研究

Effects of Wall Temperature Ratio on ShockTrain in Cylindrical Isolator

关键词:  壁温比  隔离段  激波串  反压  剪切应力

Key words:  Wall temperature ratio  Isolator  Shock train  Back pressure  Shear stress

摘要:

为明晰壁温比对圆截面隔离段激波串的影响，采用RANS方法对圆截面隔离段进行三维数值计算，发现冷壁条件下，壁温比升高将导致隔离段抗反压能力减弱。在此基础上，通过理论分析研究了壁温比对边界层的影响，发现边界层主要通过剪切应力和亚声速流层携带的流体惯性的综合作用来抵抗反压，其中剪切应力与压升作用一致，而亚声速流层携带的流体惯性与压升作用相反。考虑壁温比影响，对经典Waltrup激波串预测公式进行修正，修正后公式可以动态反映壁温比变化导致的激波串长度改变，有助于隔离段优化设计。

Abstract:

In order to clarify the effects of wall temperature ratio on shock train in cylindrical isolator, three dimensional numerical simulation was carried out by RANS method. It is found that under the cold wall condition, with the increase of wall temperature ratio, the ability of isolator to resist back pressure is weakened. On the basis, the effect of the wall temperature ratio on boundary layer was analyzed theoretically. It is found that boundary layer resist back pressure through shear stress and fluid inertial force, and shear stress has the same effect with back pressure, while fluid inertial force has the opposite effect with back pressure. The classical Waltrup shock wave prediction formula was corrected considering wall temperature ratio, and the modified formula can reflect the effect of wall temperature ratio dynamically, which is good for isolator optimization and design.