交错型篦齿对涡轮气动性能的影响

摘要

应用数值方法对某2级带冠涡轮的流场进行模拟，基于原篦齿结构，在机匣内壁固定篦齿与叶冠上的篦齿配合形成交错型篦齿，进而改变叶冠顶部的流动结构，减小叶冠泄漏流量，提高涡轮效率，同时分析了固定在机匣内壁上的篦齿形状及其高度对涡轮气动性能的影响。研究结果表明，采用交错型篦齿的涡轮效率比原篦齿结构的涡轮效率提高0．5％左右，机匣内壁上的篦齿形状对涡轮效率影响程度的优良次序为：三角齿→梯形齿→矩形齿，同时得出机匣内壁上的三角齿高为2．5 mm左右时封严性能较好。%A 2 stage turbine with shroud was studied by using a numerical simulation program.Based on the original labyrinth struc-ture, the staggered labyrinth is composed of the labyrinth on the case and the shroud.Then flow structure on the top of shroud was changed, the leakage flow decreased and the turbine efficiency increased.The effects of the shape and the height of the labyrinth on the case to the turbine aerodynamic was analyzed.The simulation results show, the staggered labyrinth make the turbine efficiency increased 0.5%comparing the original labyrinth.The order of the effects to the turbine efficiency by the shape of the labyrinth on the case is:triangle labyrinth→trapezium labyrinth→rectangle labyrinth.In addition, the sealing performance is much better when the riangle labyrinth on the case is 2.5mm high.