水蒸气喷射泵混合室内边界层脱离现象的计算流体力学研究

Computational Fluid Dynamic Study of Boundary Layer Separation in Mixing Chamber of Steam Ejector

为了深入了解水蒸气喷射泵内流场结构,采用文献[1]给出的物理模型,在保持其他条件不变情况下,采用计算流体力学模拟得到不同背压下喷射泵内部压力分布图和混合室内迹线图,模拟结果与实验数据有较好的一致性。通过分析迹线图中的边界层脱离现象和压力分布图中压力的关系,得出高压力梯度作用导致了引射流体边界层分离,而边界层分离后导致有效区减小,造成引射系数急剧下降。

The pressure profiles and the path-line distributions at different back pressures inside the steam ejector,with no change in other conditions,were numerically calculated via a number of computational fluid dynamic simulations,on the basis of the physical model,developed by Chunnanond,et al.The calculated results show that the high pressure gradient,evaluated from the pressure profiles and the path-line distributions,leads to the boundary layer separation in the mixing chamber of the steam ejector.In addition,the boundary layer separation reduces the effective area,and rapidly decreases the entrainment ratio.The simulated results were found to agree fairly well with the experimental data.