摘要
为了研究入口气流旋流角对带支撑结构轴流排气扩压段气动性能的影响,以某型燃气轮机排气扩压段为研究对象,采用数值计算的方法,对单独排气段模型及排气段和涡轮末级动叶耦合模型分别进行数值模拟。采用总压保持系数和静压恢复系数作为衡量排气扩压段气动性能的主要参数。排气段单独模拟的结果显示,当旋流角从0°变化至-32°,总压保持系数下降4%,且在-20°以后开始呈现突然的快速下降趋势;而静压恢复系数先上升后降低,在-16°时达到最大值。另外,通过耦合模型与单独排气段模型的数值计算对比,发现当排气段入口旋流角和质量流量相同时,计算结果较为一致。以上结果说明,入口旋流角是影响排气扩压段流动性能的关键因素之一,进行排气段结构设计时要充分考虑旋流角对内部流动的影响。而且,单独排气段数值模拟在相同质量流量和旋流角度条件下,可近似达到耦合模拟的精度,提高设计效率。
In order to investigate the effect of inlet swirl on the performance of an axial strutted annular exhaust diffuser,numerical method is used to study the flow field in separate exhaust hood and exhaust hood with last stage of turbine.The performance is evaluated by total pressure loss and static pressure recovery.The results of computations in separate exhaust hood shows that inlet swirl has a significant influence on exhaust losses.In this case,total pressure loss begin to increase rapidly while absolute value of inlet swirl increases to 20°.Total pressure holding coefficient decrease by 4%while inlet swirl varies from 0°to-32°.Static pressure recovery coefficient show a trend of rise before-16°,and declines after it.In addition to this,combined simulation method is used to validate the results of separate exhaust hood computation.Comparison results show that two methods are in reasonable agreement while inlet swirl and mass flow are about the same.The study shows that the impact of inlet swirl is quite important while we must take it into consideration in exhaust hood design.If appropriate boundary conditions can be given,separate exhaust hood model can also offer accurate simulation results.
作者
徐自荣
袁浩
初鹏
蓝吉兵
张春梅
隋永枫
XU Zirong;YUAN Hao;CHU Peng;LAN Jibing;ZHANG Chunmei;SUI Yongfeng(Industrial Turbine Academy Turbomechanical Institute,Hangzhou Steam Turbine Co.,Ltd.,Hangzhou 310022,China)
出处
《燃气轮机技术》
2018年第1期30-34,共5页
Gas Turbine Technology
关键词
轴流排气缸
数值分析
入口旋流角
耦合计算
axial exhaust hood
numerical analysis
inlet swirl
combined simulation
