基于流固热耦合的非金属迷宫密封泄漏特性与公式构造

Leakage characteristics and formula establishment of nonmetallic labyrinth seal based on fluid-solid-thermal coupling

建立了考虑齿变形的非金属迷宫密封泄漏特性流固热耦合数值求解模型,在验证求解模型准确性的基础上,研究了聚醚醚酮(PEEK)、填充30%碳纤维增强聚醚醚酮(PEEK-CA30)和铝合金三种材料迷宫密封在不同压比、温度下的流场特性、结构力学特性与泄漏特性,并基于Vermes公式构造了考虑齿变形的非金属迷宫密封泄漏量理论公式。研究结果表明:建立的迷宫密封流固热耦合模型可以准确计算非金属密封齿的变形量和变形后的泄漏量。在研究的三种材料中,采用PEEK-CA30材料密封齿的变形量相对较小,占密封齿径向长度的0.35%~0.67%,其密封性能较好,相比于未考虑齿变形密封的泄漏量增加1.2%~6.8%。当温度高于500 K,压比大于3时,采用铝合金材料密封齿的最大等效应力达到材料的屈服极限而引起密封件失效。所构造的泄漏量理论公式能够准确预测考虑齿变形的非金属迷宫密封泄漏量,为非金属迷宫密封泄漏特性分析提供理论依据。

Fluid-solid-thermal coupling numerical model of nonmetallic labyrinth seal leakage characteristics was established considering the deformation of tooth.The flow field,structure mechanical characteristics and leakage characteristics of polyether ether ketone(PEEK),30% carbon fiber-filled reinforced polyether ether ketone(PEEK-CA30) and aluminium alloy in three kinds of material labyrinth seal under different pressure ratios and temperature were studied on the basis of the validation to solve the model accuracy,and based on the formula for Vermes,the nonmetallic labyrinth leakage theory formula was constructed considering the deformation of tooth.The results showed that the fluid-solid-thermal coupling model of labyrinth seal can accurately calculate the deformation of nonmetallic seal teeth and the leakage rate.Among the three materials studied, PEEK-CA30 material had relatively small deformation of sealing teeth, accounting for 0.35%-0.67% of radial length of sealing teeth.Its sealing performance was good,and compared with the leakage rate without considering deformation of teeth,it only increased by 1.2%-6.8%.When the pressure ratio was more than 3 and the temperature was higher than 500 K,the equivalent stress of the seal teeth using aluminium alloy material reached the yield limit of the material,leading to the failure of the seal.The theoretical formula of leakage rate can accurately predict the leakage rate of nonmetallic labyrinth seal considering deformation of tooth,providing a theoretical basis for analysis of the leakage characteristics of nonmetallic labyrinth seal.