考虑热流固多物理场耦合的圆周密封特性

Circumferential seal characteristics with thermal-fluid-structure multi-physics field coupling

基于圆周密封工况分析,建立了流场、温度场及结构场的多物理场耦合三维求解模型。通过热流固耦合方法计算结果分别与理论模型和试验结果对比,验证了模型正确性。分析了圆周密封流场、温度场和结构场特性,及耦合场应力和变形分布规律,得到了关键工况参数对圆周密封性能作用规律。结果表明:流场压力沿z轴负向降低,压力降梯度与密封带宽度负相关;封严气体出现不规则涡旋运动,流速沿径向降低。温度场分布较均匀,最高温度位于搭接头处。结构场分析发现最大变形和最大应力位于凸搭接头处。热流固耦合下密封环最大变形量比流固耦合下增大161%,比热结构耦合下减小0.9%,温度场对变形显著影响。最大应力移至密封带与搭接头过渡处,比流固耦合下增大83%,比热结构耦合下增大23%,流场与温度场对密封环应力影响较大。温差变化对变形量起主要作用。压差变化对最大应力起主要作用,对泄漏量具有决定性作用。

Based on the analysis of circumferential seal conditions,a three-dimensional multi-physics coupling simulation model of flow field,temperature field and structural field was established.The correctness of the model was verified by comparing the results of the thermal-fluid-structure coupling method with the theoretical model and the experimental results.The characteristics of flow field,temperature field and structure field of circumferential seal,and the distribution of von Mises stress and deformation in multi-physics coupling field were analyzed,and the effect of typical condition parameters on the performance of circumferential seal was obtained.The results showed that the pressure in the flow field decreased along the negative directim of z axis,and the pressure drop gradient was negatively correlated with the seal dam width.The seal gas generated irregular vortex motion,and the flow velocity decreased along the radial direction.The temperature field was uniformly distributed,and the maximum temperature was located at the lap joint.It was found that the maximum deformation and maximum von Mises stress were located at the convex lap joint by static structural analysis.The maximum deformation of the seal ring under thermal-fluid-structure coupling was 161%higher than that of the fluid-structure coupling and 0.9%smaller than that of the thermal-structure coupling,and the temperature field had a significant effect on the deformation of the seal ring.The maximum von Mises stress shifted to the transition between the seal dam and the lap joint,83%higher than that under the fluid-structure coupling and 23%higher than that under the thermal-structure coupling;and both the flow field and temperature field had great influence on the von Mises stress of the seal ring.The change of seal temperature difference plays an important role in the deformation.The change of seal pressure difference plays a major role in the maximum von Mises stress and a decisive role in the leakage.