摘要
为进一步探索湿化燃气轮机透平循环的叶片前缘冷却情况,分析了进口雷诺数和湿空气含湿量对冲击冷却流动和传热特性的影响。建立了带有进气室、单排圆形冲击孔和冲击冷却腔的冲击冷却模型,利用ANSYS CFX软件数值研究了进口雷诺数和湿空气含湿量对冲击冷却流动和传热特性的影响,总结了湿空气冲击冷却的流动和传热规律。在此基础上,对努塞尔数与冲击孔雷诺数和湿空气普朗特数进行关联式拟合,得到了湿空气冲击冷却的传热关联式。研究结果表明:冲击冷却的冷却性能随着进口雷诺数和含湿量的增大而提高;冲击射流冲击至靶面后沿着壁面向四周流动,并在冲击腔内形成复杂的流动涡结构;增大进口雷诺数能够显著增大冷气的涡量,提高换热靶面的换热强度;相同进口雷诺数下,干空气冷却和湿空气冷却换热靶面努塞尔数分布规律一致,但数值上湿空气冷却的略高于干空气冷却的,并且二者差异随着进口雷诺数的增大而增大;冷却工质的质量流量随着含湿量的增大而减小,换热靶面努塞尔数随着含湿量的增大而增大;拟合的传热关联式与数值计算的结果吻合较好,能够较好地预测湿空气冲击冷却的换热系数。
To investigate the cooling of the blade leading edge of a humidified gas turbine,the effects of inlet Reynolds number and humidity ratio of moist air on the impingement cooling of flow and heat transfer are analyzed.An impingement cooling model with an inlet chamber,a row of circular impingement holes and an impingement cooling chamber is established.The ANSYS CFX software is used to numerically investigate the influences of inlet Reynolds number and humidity ratio of moist air on flow and heat transfer characteristics of impingement cooling,and the properties of the flow and heat transfer are summarized.Following the numerical results,the Nusselt number is correlated with the Reynolds number of impingement holes and the Prandtl number to obtain the heat transfer correlation of the moist air impingement cooling.The results show that the cooling performance of impingement cooling improves with the increasing Reynolds number and humidity ratio.After the impingement jet impacts the target surface,the coolant flows along the wall surface and forms a complex vortex structure in the impingement cooling chamber.When the inlet Reynolds number increases,the heat transfer of the target surface is enhanced due to an increasing coolant vorticity.The Nu distributions of the target surface for dry air cooling and moist air cooling have little differences with the same inlet Reynolds number,but the value of Nu for moist air cooling is slightly higher than that for dry air cooling and the difference increase with the increasing inlet Reynolds number.The coolant mass flow decreases with the increasing humidity ratio,while the Nu of the target surface increases with the increasing humidity ratio.The heat transfer correlation coincides well with the numerical results and can be used to predict the heat transfer coefficient of moist air impingement cooling.
作者
李健武
符阳春
张志伟
廖贵鄂
李亮
LI Jianwu;FU Yangchun;ZHANG Zhiwei;LIAO Gui’e;LI Liang(Institute of Turbomachinery, Xi’an Jiaotong University, Xi’an 710049, China)
出处
《西安交通大学学报》
EI
CAS
CSCD
北大核心
2020年第5期170-178,共9页
Journal of Xi'an Jiaotong University
基金
国家科技重大专项资助项目(2017-I-0009-0010)。
关键词
燃气轮机
冲击冷却
湿空气
雷诺数
含湿量
gas turbine
impingement cooling
moist air
Reynolds number
humidity ratio
