静态篦齿封严温变效应产生机理数值研究

Numerical study on the generation mechanism of temperature variation effect of static labyrinth seals

采用理论分析和数值计算的方法系统地研究了静态篦齿封严温变效应产生机理和影响因素,对静态篦齿封严温变效应进行了理论分析,建立了基于RNG(renormalization group)k-ε湍流方程的数值求解模型。研究了静态篦齿封严温变效应,分析了压比和相对封严间隙对温变效应的影响规律,揭示了静态篦齿封严温变效应产生机理。结果表明:气体流经封严间隙温度先降低后升高,从涡流中心到外缘温度升高,齿腔近壁面气体温度升高。篦齿封严局部气体温度既有升高也有降低,总体上温度沿轴向降低;静态篦齿封严气体温度随压比和相对封严间隙的增加而降低,当压比为1.6,相对封严间隙为1.6时,温降最多为4.70 K;静态篦齿封严的温变效应主要是由其节流效应、热力学效应和摩擦效应产生。气体在间隙由于节流效应,分子动能减小,在齿腔由于热力学效应,涡流中心动能传递给涡流外缘,在齿腔近壁面由于摩擦效应,气体动能转换为热能。研究成果为篦齿封严间隙气流热分析提供了理论依据。

Theoretical analysis and numerical calculation methods were used to systematically study the generation mechanism and influencing factors of the temperature variation effect of the static labyrinth seals.A theoretical analysis of the temperature variation effect of the static labyrinth seals was carried out,and a numerical solution model based on the RNG(renormalization group)k-εturbulence equation was established.The temperature variation effect of static labyrinth seals was studied,the influence of pressure ratio and relative seal clearances on the temperature variation effect was analyzed,and the generation mechanism of the temperature variation effect of static labyrinth seals was revealed.The results showed that the temperature of the gas flowing through the seal clearances first decreased and then increased,and the temperature increased from the center of the swirl to the outer edge,and the temperature of the gas near the wall of the labyrinth cavity increased.The local gas temperature of the labyrinth seals increased or decreased,and the overall temperature decreased along the axial direction;the temperature of the static labyrinth seals gas decreased with the increase of the pressure ratio and the relative seal clearances.When the pressure ratio was 1.6 and the relative seal clearances was 1.6,the temperature drop was at most 4.70 K;the temperature variation effect of the static labyrinth seals was mainly caused by its throttling effect,thermodynamic effect and friction effect.Due to the throttling effect in the clearances,the molecular kinetic energy of the gas decreased.In the labyrinth cavity,due to the thermodynamic effect,the kinetic energy of the center of the swirl was transferred to the outer edge of the swirl.Due to the friction effect on the near wall of the labyrinth cavity,the kinetic energy of the gas was converted into heat energy.The research results provide a theoretical basis for the thermal analysis of the airflow in the labyrinth seals clearances.