中文摘要：

随着高空无人飞行器研究的不断升温，高空低雷诺数条件下动力装置的研究越来越受到人们的重视．结合近年来国内外相关领域的研究工作，对低雷诺数低压涡轮内部复杂流动机理的研究进展进行了介绍，包括低雷诺数情况下低压涡轮内部非定常流动的特点，叶片边界层分离及转捩现象机理，上游周期性尾迹与下游叶片边界层相互作用机理等．在此基础上给出了适合低雷诺数条件的低压涡轮气动设计方法：尾迹通过与边界层的相互作用，能够抑制分离，进而减小叶型损失，在气动设计中有效引入非定常效应可以大幅度提高低压涡轮的气动负荷或降低气动损失，最终达到提高性能的目的；数值及实验结果验证了这种设计方法的有效性．

英文摘要：

With increasing interests on high altitude Unmanned Aerial Vehicles （UAVs）, more and more attentions have been paid to the research of aero-engines under high altitude, low Reynolds number conditions. This paper reviews the research progress on complex internal flow in low Reynolds number and low pressure turbine （LPT） in recent years. The main topics include unsteady flow characteristics of LPT, mechanisms of separation and transition phenomena of boundary layer, mechanisms of periodic wake/boundary layer interactions. Based on flow mechanisms, an aerodynamic design method for low Reynolds number LPT is proposed. The interactions of wake/boundary layer can inhibit separations and diminish profile losses. Taking unsteady effects into account in the aerodynamic design, one can effectively improve blade loading or reduce aerodynamic losses, and finally improve the performance of LPT. The numerical and experimental results validate this aerodynamic design method.