热边界对封严篦齿性能影响的数值计算

Numerical Analysis of Heating Boundary Effect on the Characteristics of Rotational Sealing Labyrinth

为了解热边界对封严篦齿的流动特性的影响,本文采用标准k-ε模型QU ICK格式、非结构化网格和S IM PLE算法,数值模拟了模化的热态封严篦齿的流动特性。求解了速度场、温度场和压力场,分析了流场特性。计算结果表明:不同压比下,热边界热流增加泄漏减小,增强了封严效果。热流密度对泄漏系数的影响规律基本呈线性变化关系。热量传递的不均匀性会导致篦齿腔内出现小旋涡,也增强了封严效果。小旋涡出现位置和旋涡大小与热边界端面的传热量和封严段前后压比有关。

The standard k-ε turbulence model,QUICK schemes,non uniform grid and SIMPLE method were applied to the calculations of flow field characteristics for the modeled sealing labyrinth with heating boundaries. It is aimed at investigating the effect of heating boundary. The velocity, temperature and pressure fields were obtained and the flow characteristics were discussed. The computational results state that the leakage goes down as heat flux of the heating boundary rises ,and thus the sealing effectiveness under different pressure ratios is enhanced. The results also show that the sealing effect and the heat flux are linearly related. The uneven distribution of the heat transfer causes to produce small eddy at the cavity of the labyrinth and an increase in the sealing effectiveness. The location and size of the small eddy depend on the heat flux on the wall of the heating boundary and the pressure ratio.