进口总压不均匀性对燃气透平端壁气热特性影响的研究

Effects of Inlet Total Pressure Non-Uniformities on Aero-Thermal Performance of Gas Turbine Endwalls

关键词:  燃气轮机  总压不均匀性  端壁  二次流  传热

Key words:  Gas turbine  Total pressure non-uniformity  Endwall  Secondary flow  Heat transfer

摘要:

为了研究非均匀进口总压引起的燃气透平内部流动特性变化对静、动叶端壁传热的影响机制，针对GE-E3透平第一级叶片在均匀、湍流边界层及航空发动机燃烧室出口实测得到的“C”型总压三种进口条件下进行了非定常数值计算。研究表明:非均匀进口总压相对均匀进口条件对静叶端壁附近流速和入口三角区传热产生了显著影响；湍流边界层总压相对均匀总压增强了前缘马蹄涡强度，从而使静、动叶端壁前缘传热系数分别增加100%和30%；“C”型总压使静叶端壁分离线下游和动叶端壁前缘局部传热系数降低；静叶内被湍流边界层总压增强的通道涡和由“C”型总压诱导产生的对转涡均会出现在动叶上下端壁附近；残余通道涡削弱了动叶端壁横向流动并使对应位置传热系数最大降低了12%，残余对转涡则增强了动叶端壁横向流动并使端壁传热系数最大增加了38%。

Abstract:

To investigate the effects of the variations of turbine flow patterns induced by the non-uniform inlet total pressure on turbine stator and rotor endwall heat transfer characteristics， unsteady numerical simulations were conducted using the first stage airfoils of GE-E3 turbine with three inlet total pressure profiles. The three total pressure profiles include uniform total pressure， turbulent boundary layer total pressure， and “C” type total pressure measured at an engine combustor exit. The results show that comparing with the uniform case， total pressure non-uniformities have significant impacts on the fluid velocity near stator endwall and thus the heat transfer at the entrance triangular area. The turbulent boundary layer total pressure intensifies the horse-shoe vortices and increases the stator and rotor endwall leading edge heat transfer coefficients (HTC) by 100% and 30%， respectively. While the “C” type total pressure decreases the HTC downstream of the list-off line on stator endwall and at the certain regions of rotor endwall leading edge. The passage vortices intensified by turbulent boundary layer total pressure and counter-rotating vortices induced by “C” type total pressure in the stator passage will still exist in the rotor passage near endwalls. The residual passage vortices weaken the rotor endwall cross-flow and result in maximal HTC decline of 12% at the corresponding region. Conversely， the residual counter-rotating vortices intensify the rotor endwall cross-flow and induce maximal rotor endwall HTC increment of 38%.