1.5级涡轮实验台前腔燃气入侵实验

在1.5级涡轮实验台上，针对不同转速和不同封严质量流量，分别采用稳态压力测量、瞬态压力测量和二氧化碳体积分数法对燃气入侵现象进行了实验研究，以确定不同工况下主流的动静叶相互作用对燃气入侵的影响以及入侵到盘腔的燃气在腔内与冷气的掺混过程.结果表明:静叶后的时均压力在周向有明显的周期分布，部分区域封严环外的压力高于腔内压力，且随着封严质量流量增加，这一区域逐渐缩小；动叶扫掠带来同频率的压力波动，对于燃气入侵的发生有着重要的影响；通过二氧化碳体积分数实验获得了最小封严质量流量，并得到在封严质量流量不足情况下燃气沿着静盘侧入侵盘腔的结果. 

Experiment on gas ingestion on forward disk cavity of 1.5 stage turbine rig

An experimental investigation on the gas ingestion phenomenon was performed on the rig of 1.5 stage turbine with different rotating velocities and seal mass flow rates. The experimental measurements include time-average and unsteady pressure field measurements and carbon dioxide volume fraction technique. These data were used to find out the influence of the interaction between rotor blades and stator blades on the phenomenon of gas ingestion and investigate the details during the process of the main gas into the cavity. The study suggests that, some part of the pressure on the annulus out of the seal in higher than the pressure inside seal rim due to the circumferential variation following the vane pitch. And this part decreases as seal mass flow rate increases. An unsteady blade-periodic component is found in this experiment, which is also a key to ingestion. The minimum necessary value of seal mass flow rate is obtained by carbon dioxide volume fraction technique. And the fact that the path of the main gas ingestion into the disk cavity is arranged along the stator when seal mass flow rate is not enough can also be inferred.