船舶间冷循环多级动力涡轮气动优化设计

Aerodynamic Design Optimization of a Marine Multi-Stage Power Turbine Operating in an Intercooled Cycle

关键词:  间冷循环  多级涡轮  先进涡设计  粘性  设计优化

Key words:  Intercooled cycle  Multi-stage turbine  Advanced vortex design  Viscosity  Design optimization

摘要:

为了进行燃气轮机的间冷循环改造研究，需要对动力涡轮进行高效大功率重新设计。传统的准三维设计，由于对粘性影响的估算精度不够，导致设计和实际结果有一定偏差，尤其是对于多级涡轮设计，不但恶化了端部流场，还容易导致级间参数不匹配等问题。而近些年来的各种优化理论应用涡轮设计过程，由于计算量大、计算时间长、变量样本空间过于庞大，在实践中往往设计周期长，且难以有效实现。考虑了近端壁处粘性的影响，发展了一种基于传统无粘可控涡设计的局部环量再分布的先进涡设计技术，尽力减少端部二次流损失，并且改善叶片列间的匹配性能。基于CFD软件平台，将所发展的先进涡设计、级环境下单列叶栅局部优化和多级涡轮匹配优化联合实现多级涡轮的气动优化设计。最终所设计的间冷循环五级动力涡轮在满足设计流量的前提下，功率比设计值略高，轮周效率提高了1.36%，达到了轮周效率提高1%的设计要求。

Abstract:

In order to study the design process of intercooled cycle gas turbine，a high-efficiency and large-power turbine for gas turbine needs to be redesigned. Due to the fact that the effects of viscosity are not accurately estimated，the traditional quasi-three dimensional design has a disadvantage that there is a certain deviation between design results and actual results. It can bring many problems，for example，the endwall flow deterioration，parameters mismatch among the turbines stages. Those problems often appear in the design process of multi-stage turbines. In recent years，various optimization theories have been applied to the process of turbine design. However，due to massive calculation，long-time calculation，and huge variable sample space，those theories have long design-periods and are difficult to achieve in practice. The effects of viscosity near the endwalls were taken into account. An advanced vortex design technique was developed which is based on the local circulation redistribution of traditional non-viscous controlled vortex design technique. It can reduce endwall secondary flow losses and improve the matching performance of blade rows. Based on the computational fluid dynamics (CFD) platform，the advanced vortex design technique as mentioned，and single cascade local optimization in stage environment with matching optimization technique of multi-stage turbines were combined to achieve multi-stage turbine aerodynamic optimization design. Finally，on the premise of achieving the target of design mass flow rate，the five-stage power turbine in an intercooled cycle has obtained higher power as compared to the design goal，and the wheel efficiency rises by 1.36%，accomplishing the design goal of rising the wheel efficiency by 1%.