加力燃油泵隔舌分离流的大涡数值模拟  

Large eddy simulations of separated flow at the casing tongue of an afterburner fuel pump

作　　者：薛梅新[1] 朴英[1] 

机构地区：[1]清华大学航天航空学院,北京100084

出　　处：《清华大学学报（自然科学版）》2012年第11期1638-1642,1649,共6页Journal of Tsinghua University(Science and Technology)

摘　　要：针对某型航空发动机的加力燃油泵隔舌空蚀破坏,采用动态亚格子应力模型对不同流量工况下加力泵内非定常流场进行大涡模拟,分析环形腔室隔舌附近分离流动规律及瞬时压力特性,探讨隔舌空蚀破坏发生工况。计算结果表明:在全开加力工况下,伴随隔舌附近分离涡的周期性增长与脱落,隔舌处监测点压力脉动幅值达14%,而下游监测点压力脉动幅值仅3%;在小加力工况下,扩散管内阻滞燃油绕流隔舌返回环形腔室,隔舌附近流动严重分离,分离涡的脱落使得隔舌处瞬时静压达到负值,分离再附位置与隔舌空蚀破坏核心区域相符。在全开加力工况下,隔舌附近不会发生空化;而在小加力工况下,隔舌分离流会诱导空化并导致空蚀破坏。To solve the uncommon cavitation damage problem near the casing tongue of an afterburner fuel pump on a certain type of aero-engine, the unsteady flow field inside the pump at different flow rates was studied by large eddy simulations with the dynamic subgrid-scale stress model. The separated flow characteristics and pressure fluctuations around the casing tongue were analyzed to find the conditions causing the cavitation. The results show unsteady separating eddies near the casing tongue. At full afterburner conditions, with the periodic growth and shedding of the separation eddies, the monitoring pressure fluctuation amplitude at the casing tongue reaches 14%, while the amplitude is only 3% downstream. At low flow conditions, the blocked fuel in the diffuser flows over the casing tongue back to the annular chamber, which triggers serious separation. The shedding of the separated vortex lowers the static pressure at the casing tongue to less than zero with the separation point in accord with the cavitation damage core region. Thus, at full afterburner conditions there is no cavitation near the casing tongue, while at low flow conditions the separated flow induces cavitation and damage.

关 键 词：加力燃油泵 隔舌 分离流 大涡模拟 

分 类 号：V233.2[航空宇航科学与技术—航空宇航推进理论与工程]