凸起迎风面积对不同轮缘封严结构封严效率影响的实验研究

Experimental Study on Effects of Section Area of Protrusionon Sealing Efficiency of Different Rim Seal

关键词:  转静系  轮缘封严  凸起迎风面积  封严效率

Key words:  Rotator-stator system  Rim seal  Protrusion section area  Sealing efficiency

摘要:

为了获得合适的凸起迎风面积并为减缓燃气入侵提供依据，用CO₂浓度测量法研究了凸起迎风面积的变化对涡轮腔内各参数(静压、总压、浓度)的影响，揭示了关于不同封严结构的封严效率和最小封严流量随凸起迎风面积改变的规律。试验在主流雷诺数[Rew]=4.39×105，旋转雷诺数在7.51×105<[Re?]<1.30×106的范围内，测得了不同封严冷气流量下的实验参数。结果表明:试验设计工况范围内，凸起的迎风面积改变对涡轮腔内的静压影响不大，靠近封严环处的静压变化几乎可以忽略不计；而总压和封严效率都和凸起迎风面积成正比关系，但不同封严结构的提升程度存在差别。整体而言，径向封严结构效率的增大最突出，轴向封严和静盘双齿封严改善略小。安装凸起后，平均来看，三种结构所需的最小封严流量分别可以减少11.8%，5.3%，3.4%。此外，旋转雷诺数对封严效率的影响也很明显。

Abstract:

In order to obtain the appropriate protrusion section area and provide a basis for relieving the gas ingestion， the effects of different section area of protrusion on various parameters (static pressure， total pressure， concentration) were studied by measuring CO₂ concentration， exposing the change rule of the sealing efficiency and the minimum flow rate of sealing air of the different sealing structure. In the experiment， the experimental parameters of different dimensionless sealing flow were measured under the condition that the annulus Reynolds number ([Rew]) was 4.39×105 and the rotating Reynolds number ([Re?]) changed from 7.51×105 to 1.30×106. The results show that the change of the section area of protrusions has little effect on the static pressure in the cavity， and the static pressure change near the sealing ring is almost negligible. The total pressure and sealing efficiency will increase with the increase of the section area of protrusion. However， the degree of change in the three sealing structures is different. As a whole， the effect of radial rim seal is most obvious， and the improvement of axial and double teeth rim seal are less. On average， after the protrusions are installed， the minimum seal flow required for the three structures can be reduced by 11.8%， 5.3% and 3.4% respectively. In addition， the rotating Reynolds number will also have a significant impact on the sealing efficiency.