烟气轮机叶顶隙中气相运动规律的模拟

摘要

针对烟气轮机催化剂结垢问题,采用可压缩流体的标准k-ε湍流模型,对烟气在烟机叶顶隙的气相运动规律进行研究.研究表明:静叶内,间隙流压能、热能的下降量以及烟气速度的提高量都要比主流小;动叶内,主流因为做功,速度不断减小,间隙流受主流的影响烟气速度先增大后减小;静叶叶顶隙存在回流,靠近叶片处烟气速度减小,催化剂颗粒容易沉积;动叶叶顶隙出现了漩涡,叶尾处存在二次流,这些都容易造成催化剂颗粒的沉积;静叶叶顶隙与叶片对应的位置泄漏率不断增大,动叶叶顶隙与叶片对应的位置泄漏率不断减小.%The energy saving effect of flue gas turbine is considerable,but it often breaks down.Although the tip clearance size is very small,it has a great influence on the channel.In view of the problem of flue gas turbine catalyst scaling,the standard k-ε two equation turbulence model of the compressible fluid was employed to simulate the gas flow in the flue gas turbine cascade and the tip clearance.The results show that in the static blades,the decrease of gap pressure energy and heat energy and the increase of flue gas velocity are smaller than the mainstream.In the moving blades,mainstream speed decreases due to work.The velocity of the gap flow increases and then decreases with the influence of the main flow.Circumfluence occurs in the tip clearance of the stator blade.The flue gas velocity near the blade decreases,so the catalyst particles are easily deposited.Vortex occurs in the tip clearance of the moving blade.The secondary flow is generated at the moving blade tail.These factors are likely to cause the deposition of catalyst particles.In the tip clearance of the stator blade,the leakage rate corresponding to the position of the blade is increasing.In the tip clearance of the moving blade,the leakage rate corresponding to the position of the blade is decreasing.