对开式向心涡轮背部间隙流动特性进行计算分析，计算结果和实验符合较好。分析结果表明：背部间隙泄漏流量远小于叶顶间隙泄漏流量，但两者损失大小相当，可见背部间隙与叶顶间隙虽然在形式上相似，但流动特性及损失机理有所不同；背部机匣刮削效应增强了展向二次流强度，在吸力面附近出现较大的高熵区，同时背部间隙泄漏流在展向二次流的带动下源源不断向叶顶方向运动，与主流形成较强的掺混；相比之下，叶顶机匣刮削流和展向二次流相互抵消，叶顶间隙泄漏流被展向二次流限制在叶顶壁角附近，掺混损失相对较小。
Numerical simulation is presented to investigate the backface clearance flow in a deeply scalloped radial turbine, CFD results agree well with experimental data for code certification. It is shown that the backface clearance flow, with significantly less leakage flow rate, accounts for nearly the same loss than the tip clearance flow, so we can see that backface and tip clearance have similar configurations but different flow characteristics effect strengthens the spanw[se secondary flow, and loss mechanisms; The backface casing scraping which causes higher entropy near the suction side wall, and the spanwise secondary flow ＂pushes＂ the backface clearance leakage flow up into the blade tip region, which results in a large mixing loss; On contrast, the spanwise secondary flow is offseted by the tip casing scraping flow, and the tip clearance leakage flow, which is constrained near the tip side wall by the spanwise secondary flow, has relatively less mixing loss.
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