基于双吸叶轮两侧非均衡进气研究轮盘凸台尺寸影响

Effects of Hub Radial Portion Scale on Performance of a Double-Sided Centrifugal Compressor Impeller under Un-Equilibrium Inlet Condition

为明确双吸叶轮两侧叶轮之间的径向轮盘凸台尺寸变化对其总体性能及内部流场的影响,探索不同尺寸轮盘结构叶轮的流动损失机理,基于双吸叶轮两侧非均衡进气条件,采用数值方法对五种径向轮盘尺寸双吸叶轮的三维粘性流场进行了模拟研究。研究结果表明:从双吸叶轮最优性能及最高流动稳定性观点出发,均要求两侧叶轮之间的径向轮盘凸台超出叶片尾缘一定范围;具体超出尺寸范围则需要通过对双吸叶轮的压比、效率性能目标进行折衷确定。径向轮盘凸台尺寸的改变明显影响双吸叶轮两侧叶轮的流量分配,进而影响扩压器内分离流动损失大小及双吸叶轮的整体性能。另外,相比于较大径向轮盘凸台,无径向轮盘凸台结构更容易造成双吸叶轮两侧叶轮流量差距悬殊。

To expose the effects of hub radial portion scale in a double-sided centrifugal compressor im- peller on performance and inside flow structure, numerical simulation was carried out on a double-sided im- peller with five different hub radial portion scales under un-equilibrium inlet condition. The simulation re- sults show that, the hub radial portion is expected to exceed blade trailing edge, from both performance and flow stability standpoint. The best hub radial portion scale should be optimized based on impeller pressure ratio and efficiency performance compromise. The hub radial portion directly affects the double-sided impel- ler mass flow rate in both sides, hence the impeller performance. Due to the effect on the mass flow rate, different hub radial portion configuration can modify separation flow in downstream diffuser. The minimum hub radial portion impeller configuration tends to make the mass flow rate between front side and rear sideunbalanced more easily than any other configurations.