【摘要】 分别对海豚型叶型和常规设计的蒸汽轮机叶型进行了一级全三维气液两相数值计算,对比发现所设计的海豚型叶型在改善常规叶型流场的气动性能、提高汽轮机轮周效率的同时,可以提高流道内叶片段区域的湿蒸汽干度,改善流道内湿蒸汽的分布。海豚型叶型具有短的扩压段,使激波和附面层干扰区域具有更强的防汽流脱落能力,这样可减少此区域内水膜被高速汽流急剧撕裂成二次水滴的可能。海豚型叶型通道内湿蒸汽湿度沿叶高的分布特点有利于在叶片上表面开设除湿槽,进行高效除湿。更多还原

【Abstract】 A new kind of steam turbine last stage with the dolphin blade instead of the traditional blade was introduced for investigation.The flow fields of the dolphin blade and the traditional blade cascade were comparatively analyzed by two-phase flow numerical simulation of steady three dimensional N.S solvers based on wet steam physics characteristics.The computation results indicate that the use of the dolphin cascade effectively improves the aerodynamic performance of the flow flied,the stage wheel efficiency is increased,the steam mass fraction is enhanced,the distribution of wet steam is improved,the flow loss is reduced.Owing to the short diffuser of the dolphin channel,the interaction of the channel shockwave and the boundary layer can largely avoid flow shedding,so there is reduced possibility of sharply tearing the water film on the blade surface into coarse droplets in a high velocity flow.By contrast,for the dolphin cascade the steam wetness distribution along the blade height is convenient for setting the steam extraction slot on the upper blade surface.更多还原