摘要
为获得涡轮机匣内部冷却结构的换热特性,利用瞬态液晶技术测量了动力涡轮机匣中环腔及机匣后腔内表面的换热系数,获得了进口雷诺数(Re=3.0×10^(4)-9.5×10^(4))和出流比(M=0.5~2.0)影响下机匣内表面的换热规律。结果表明:机匣内表面换热系数随射流雷诺数的增大而升高,冲击射流在轴向及周向的发展使得环腔表面形成三角形和圆形高换热区。射流冲击倾斜靶面后,贴壁射流对后腔上表面形成二次冲击,提升了局部换热系数。对后腔下表面而言,随着出流比的增加,冲击靶面上游区域平均努塞尔数逐渐增加,最大增幅分别为8.5%和12.3%,而靶面下游区域平均努塞尔数逐渐减小,最大降幅分别为18.5%、26.3%和34.6%。对后腔上表面而言,出流比的增大对换热系数影响很小。
In order to obtain the heat transfer characteristics of the internal cooling structure of turbine casing,transient thermochromic liquid crystal test technology was used to measure the heat transfer coefficient on the inner surface of the annual cavity and rear cavity.The combined effect of Reynolds number and outflow ratio on the detailed distribution of Nusselt number were studied for 3×10^(4)≤Re≤-9.5×10^(4)and 0.5≤M≤2.0.The results indicate that in the range of Re number studied in present paper,the Nusselt number on the surface of turbine casing increases as the Reynolds number increases.The development of the jet-flow in the circumferential and axial directions make the surface near the entrance of the annular cavity appear triangular and circular high heat exchange zones.After the jet impacts the inclined target surface,the adjoining jet forms a secondary impact on the up surface of the back cavity,which strengthens the local heat transfer coefficient.As the increasing of the outflow ratio,the average Nusselt number on the upstream region of the stagnation area gets higher accordingly and the maximum increases are 8.5%and 12.3%for each,while the average Nusselt number on the downstream region becomes down relatively and the maximum decreases are 18.5%,26.3%and 34.6%for each.The change of outflow ratio has little effect on average Nusselt number of the up surface.
作者
邱长波
李国栋
郭涛
刘存良
朱惠人
QIU Chang-Bo;Li Guo-Dong;GUO Tao;LIU Cun-Liang;ZHU Hui-Ren(AECC Hunan Aviation Powerplant Research Institute,Zhuzhou 412002,China;School of Power and Energy,Northwestern Polytechnical University,Xi'an 710129,China)
出处
《工程热物理学报》
EI
CAS
CSCD
北大核心
2021年第9期2333-2344,共12页
Journal of Engineering Thermophysics
关键词
涡轮机匣
射流冲击
瞬态液晶
出流比
换热系数
turbine casing
impinging jet
transient thermochromic liquid crystal
outflow ratio
heat transfer coefficient
