加力燃油泵压出室非设计工况内流特征数值模拟

针对某型航空发动机加力燃油泵隔舌空蚀破坏,采用滑移网格技术模拟泵内非定常流场,揭示了压出室在典型非设计工况下的内流特征,研究了隔舌处的空化机理.计算结果表明:大流量工况,扩散管锥形段存在大小两个分离涡,而环形腔室隔舌段燃油以相切方式流经隔舌壁面,无明显流动分离,不会发生空化;而小流量工况,扩散管锥形段内两分离涡扩展到大部分区域,右半侧部分阻滞燃油在反向流向涡作用下,绕流隔舌上部,在隔舌下游形成了明显分离涡,导致隔舌壁面静压急剧降低,进而引发空化,产生空蚀破坏. 

Numerical simulation on internal flow characteristics in the discharge chamber of an afterburning fuel pump under off-design conditions

The unsteady flow in an afterburning oil pump on a certain type of aero-engine was simulated for the uncommon cavitation damage problem near its casing tongue,with arbitrary sliding mesh technology.The discharge chamber internal flow characteristics at off-design conditions were investigated to find out possible conditions causing the casing tongue cavitation.The results showed that:under large flow-rate condition,there are two separated vortices of different sizes located in the cone-shaped tube passage,while the fuel flowed past the casing wall without obvious separation in the annular chamber,which hardly trigger cavitation;under small flow-rate condition,the two separated vortices extend to take up most part of the cone-shaped passage,incoming flow of the diffuser is choke up with a part of the fuel blocked at right side flowing back to the annular chamber around the tongue.As a result,serious flow separation is raised with a high pressure decrease,which is expected to generate cavitation and following damage on the casing tongue.