【作者】 邓庆锋；

【导师】 郑群；

【作者基本信息】 哈尔滨工程大学 ， 轮机工程， 2013， 博士

【摘要】 涡轮气动设计是叶轮机械领域的一个非常重要的研究方向，在推动高性能航空发动机以及地面燃气轮机发展上起着举足轻重的作用。随着计算流体力学的进步，涡轮设计技术也得到了快速发展，然而涡轮气动设计仍是一个十分具有挑战性的研究课题。本文对涡轮的压力可控涡气动设计机理进行了一系列研究，主要包括以下几个方面的工作：首先，本文提出了涡轮的压力可控涡设计方法，并基于此方法设计了一个单级涡轮。与传统可控涡控制切向环量cur和轴向速度cz分布有所不同，压力可控涡方法主要控制轴向速度cz和径向压力p的分布。通过控制轴向速度cz建立了与子午流面之间的联系，致使流面发生变化，从而在叶栅通道内诱导产生了较大的二次涡，有效地抑制了通道涡的生成与发展。通过径向压力p又将流体运动的宏观驱动力关联起来，从而将流面变化与压力控制有机地结合起来，更好地发挥了可控涡设计效果。这种设计方法旨在合理利用和控制叶栅流道中的二次流的产生与迁移，其核心概念是通过改变不同展向位置处的叶栅负荷来控制最为主要的径向压力梯度。同时，这种设计方法不仅对叶型升力产生了影响，相应的叶栅喉部宽度、反动度以及质量流量沿径向的分布也都发生了改变或者进行了重新分配。在涡轮总流量保持不变的前提下，采用压力可控涡设计的涡轮级总体效率明显获得提升。此外，压力可控涡设计只改变了叶型气流角和安装角，并没有对端壁型线、叶栅积叠线以及节距比进行优化。其次，在径向压力梯度控制的基础上，结合三维压力控制措施提出了一种三维压力可控涡设计方法，与先进叶型技术、弯掠叶片技术以及可控子午端壁技术一起形成了一套高性能涡轮设计框架。通过压力可控涡诱导流道内流面厚度变化及流面发生挠曲，合理地利用和控制了叶栅中的旋涡流动，从而在叶片表面形成了有利的边界层流动，降低了二次流损失。通过进一步控制径向、流向以及周向三个方向的压力分布使各个方向的压力梯度合理匹配，在上述区域形成有利的压力场，从而有效地控制了边界层的分离与增厚，减少了相应损失。运用三维压力可控涡设计对某低压涡轮第一级进行了重新设计，设计结果表明新设计涡轮等熵效率提高了0.76%，功率提高了0.6%，而流量与原型保持一致。此外三维压力可控涡设计还改善了大子午扩张涡轮的动静叶匹配特性。最后，应用三维压力可控涡方法对某多级涡轮进行了重新设计，设计过程中采用了整体设计逐级校核的设计思想，并对多级涡轮级间匹配问题进行了深入研究。运用数值模拟对多级环境下的三维压力可控涡设计效果进行了系统分析，计算结果表明：三维压力可控涡设计的多级涡轮具有良好的变工况性能，在整个运行工况范围内涡轮效率和功率均有大幅度提升。数值结果充分展示了三维压力可控涡设计的优越性。尽管多级涡轮三维压力可控涡设计是在单一设计工作点下进行的，然而新设计涡轮性能无论在设计工况还是非设计工况均得到了有效改善。更多还原

【Abstract】 Turbine aerodynamic design is an important research direction of turbomachinery,playing a significant role in high performance aeroengine and gas turbine. With the rapiddevelopment of computational fluid dynamics (CFD) and blade modeling method, turbineblade design technique has been developed speedily. Nevertheless, turbine aerodynamicdesign is still a challenge reaseach topic. A series of research about turbine design have beenconducted in this thesis. These studies mainly consist of the following aspects:Firstly, a turbine design method based on Pressure Controlled Vortex Design (PCVD) ispresented to design a small size turbine stage. Contrary to conventional CVD method withdirect assumptions of tangential circulation cur and axial velocity czdistributions, the mainobjective of PCVD is to control the axial velocity and radial pressure in the stator-rotor gap.Through controlling axial velocity cz, the PCVD establishes a direct tie to meridional streamsurface. Thus stream surface variation is induced, resulting in a large secondary flow vortexcovering the full blade passage in respective stator and rotor. This secondary flow vortexcould be dedicated to control passage vortex generation and development. Through radialpressure p, the PCVD is also associated with macroscopic driving force of fluid motion. Sothe stream surface variation and pressure are organically unified in order to achieve betterbenefit of CVD. The emphasis of this design method is secondary flow mitigation andmigration. Core concept behind PCVD is to mainly control the spanwise pressure gradient byaltering profile loading at various spanwise locations. Therefore not only the local profile liftis affected, but also the resulting throat widths, stage reaction degree and massflow rate arealtered or redistributed respectively. With the PCVD method, the global stage efficiency isincreased successfully while mass flow rate keeps constant. Additionally there is no endwallshape optimization, stacking optimization or pitch/chord variations, concentrating solely onvarying blade profile deflections and stagger.Secondly, based on the radial pressure control, a3D PCVD method incorporating3Dpressure control approach into PCVD technique is proposed and a high performance turbinedesign framework including advanced blading,3D geometry features as well as endwallprofiling is formed. Via stream surface thickness variation and stream surface deflection induced by PCVD, the secondary flow vortex in cascade is rationally utilized and dominated.A well-posed boundary layer flow pattern is presented, so the relevant secondary flow lossesare reduced largely. Through further control of spanwise, streamwise and azimuthal pressure,favorable pressure gradients are achieved in the above three directions. Not only canboundary layer separation and thickening be effectively controlled, but also profile loss canprofit. The3D PCVD results of the first stage in a low pressure turbine demonstrate that thenew design turbine isentropic efficiency increases by0.76%and the power rises by0.6%withthe massflow unchanged. The3D PCVD also greatly increases the turbine root reaction andsignificantly improves the matching characteristics between stator and rotor in a largemeridional expansion turbine.Finally a multi-stage3D PCVD method is developed and demonstrated with amulti-stage low pressure turbine in this thesis. The design process has been carried out basedon stage-by-stage design approach and the stage matching is also interpreted for effectivedesign. A systematic investigation has been carried out to evaluate the3D PCVD effects in amulti-stage turbine environment. An optimal design over the entire operating range isachieved relative to the baseline turbine and the3D PCVD turbine has fine off-designperformance. Numerical results fully demonstrate the advantage of this design method.Although3D PCVD is executed at design condition, the multi-stage turbine performance atoff-design condition has improved greatly simultaneously.更多还原