采用数值方法对某0.6 L二冲程汽油机涡轮增压器的径流涡轮进行研究，发现不同的涡轮轮盘结构对轮背间隙泄漏流影响较大。轮背泄漏流进入主流道后会形成大尺度通道涡，导致涡轮效率下降，其中开式轮盘结构的影响最大，涡轮效率最低，而扇形和闭式轮盘结构能够有效减弱甚至消除轮背间隙泄漏流，涡轮效率分别提高1.1%～1.6%和3.2%～3.5%。轮背泄漏流在径流涡轮叶片前缘叶根区域产生了高激振力，且不同轮盘结构在该区域都存在高激励区，但范围依次减小。对比分析发现，开式轮盘结构涡轮由于高激励区和高模态振幅区在叶片前缘位置叠加，导致广义压力大幅提升，而扇形轮盘和闭式轮盘涡轮的叶片前缘高激振力区未出现高模态振幅，其最大广义压力分别降低了74%和78%。不同涡轮轮盘结构的模态分析表明，扇形和闭式轮盘的一阶频率相比开式轮盘涡轮分别提高了44.5%和51.1%，使得共振工况更难激发，从而进一步提升其可靠性。扇形轮盘结构可以兼顾轮背间隙泄漏导致的涡轮效率下降和叶片高周疲劳失效问题。

A numerical method was used to study the radial turbine of a 0.6 L two-stroke gasoline engine turbocharger, and it was found that different turbine disc structures have a significant impact on the leakage flow through the backface clearance. The backface clearance leakage flow formed a large-scale channel vortex after entering the main flow channel, which reduced turbine efficiency. Among the three types of structures, the deeply scalloped turbine had the greatest impact, therefore resulting in the lowest turbine efficiency. In contrast, the scalloped and unscalloped disc structures could attenuate or even eliminate the backface clearance leakage flow, increasing the turbine efficiency by 1.1% to 1.6% and 3.2% to 3.5%, respectively. The backface clearance leakage flow generated high excitation forces in the leading edge root area of radial turbine blades. All different disc structures had such high excitation zones in this area, although the range decreased successively. The comparative analysis showed that the deeply scalloped turbine experienced significantly higher generalized pressure due to the partial coincidence of high excitation zones and high modal amplitude regions at the blade leading edge. However, the high excitation force zones at the leading edge of the scalloped and unscalloped turbine did not overlap with high modal amplitudes, resulting in maximum generalized pressure reductions of 74% and 78%, respectively. In addition, combined with the modal analysis of different turbine disc structures, the first-order frequencies of scalloped and unscalloped turbines increased by 44.5% and 51.1% compared to the deeply scalloped turbine, respectively. These high frequencies made resonance conditions less likely to occur under operational loading, thereby enhancing structural reliability. Accordingly, the scalloped disc structure achieved an optimal compromise between minimizing turbine efficiency losses caused by backface clearance leakage and mitigating the risk of high-cycle fatigue failure of the blades.