为提升船用低速机涡轮增压器性能，对增压器涡轮排气壳底部流道结构进行参数化，设计并开展了以效率为优化目标的四因素三水平正交试验优化设计和增压器整机性能试验。首先，采用CFD数值模拟方法对不同参数组合的涡轮气动性能进行了计算，然后对涡轮排气壳底部流道结构参数开展了灵敏度分析，同时针对不同参数组结构开展了内部流场对比分析，明确结构因素对流动的影响机理；在此基础上对优化后方案开展了涡轮特性分析，最后在低速双燃料机平台上开展增压器整机试验验证。分析研究表明：在涡轮进气壳、喷嘴环和涡轮叶片等通流部件结构不变的前提下，涡轮排气壳排气方向轴向长度对涡轮整级效率的影响最大，优化后效率明显提升，设计点总压损失系数降低0.3874，静压恢复系数提升0.537，总静效率提升1.85%，其余工况总静效率最大提升24%。试验结果表明：优化后涡轮增压器整机效率在主机燃油模式和燃气模式下的全工况范围内效率均有提升，最大提升幅度分别达到1.4%和2.1%，涡轮性能和增压器整机性能改善明显。

In order to improve the performance of marine lowspeed turbocharger, the flow channel structure at the bottom of turbine exhaust hood of turbocharger was parameterized, and the orthogonal test with fourfactor and threelevel based on efficiency optimization were designed to test the overall turbocharger performance. Firstly, the aerodynamic performance of turbine of different parameter combinations was calculated by CFD numerical simulation method, and then the sensitivity analysis of the structural parameters at the bottom flow channel of the turbine exhaust hood was conducted. Meanwhile, the comparative analysis of the internal flow field was carried out according to the structures of different parameter groups, so as to clarify the mechanism of structural factors influencing the flow; on the basis, the turbine characteristics of the optimized scheme were analyzed. Finally, the test verification of the overall turbocharger was carried out on the lowspeed doublefuel engine platform. The analysis result shows that the axial length of the turbine exhaust hood in the exhausting direction makes the greatest influence on the turbine stage efficiency, on the premise that the structure of flow passage components such as turbine inlet housing, nozzle ring and turbine blade remains unchanged. The efficiency is significantly improved after optimization. The total pressure loss coefficient at the design point decreases by 0.387 4, the static pressure recovery coefficient increases by 0.537, the total static efficiency increases by 1.85%, and the total net efficiency maximally increases by 2.4% under other working conditions. The test results show that the overall efficiency of the optimized turbocharger is improved in the full operating range of both main engine fuel mode and gas mode, with a maximum increase of 1.4% and 2.1%, respectively. The turbine performance and the overall turbocharger performance are improved obviously.

TK421

船用低速机（一期）——船用低速机增压器研制项目（cstc2018jszxcyzd0151）