超高速涡轮泵机械密封热弹流润滑特性研究

以超高速涡轮泵用机械密封为研究对象，针对超高速工况下密封界面多场耦合变形行为和热弹流润滑特性不明等问题，建立密封动静环和润滑液膜的耦合数学模型，研究不同转速和密封压力下的密封界面润滑特性和端面变形行为，分析相应的密封性能变化规律。结果表明：超高速工况下密封端面产生沿泄漏方向收敛的液膜间隙，密封动环的高温热变形是主因；随密封压力的增大，液膜间隙的收敛角减小，最大膜厚和泄漏率增大，端面温升明显减小；随着转速的增大，液膜间隙的收敛角、端面温升和泄漏率增大，摩擦扭矩减小。建立的流固热力耦合模型可为超高速涡轮泵用机械密封端面的优化设计提供理论指导。

Study on Thermo-elasto-hydrodynamic Lubrication Characteristics of Mechanical Seal for Ultra High-speed Turbopump

Aimed at the ultra high-speed turbopump mechanical seal,in view of the unclear problems on thermo-elasto-hydrodynamic lubrication characteristics and deformation behavior of sealing interface due to the multi-field coupling effect under the ultra high-speed operating conditions,a mathematical model was proposed on the seal rings(rotor and stator) and lubrication liquid film.The end face lubrication characteristics and deformation behavior were investigated at the different seal pressures and rotational speeds.The sealing performance laws with the operating conditions were analyzed.Numerical results show that the convergent film gap along the leakage direction is generated in the sealing interface at the ultra high-speed conditions due to the thermoelastic deformation of the seal rotator.With the increase of seal pressures,the coning angle of the convergent film gap decreases,the maximum film thickness and leakage rate increase,the temperature rise on the end face significantly decreases.With the increase in the rotational speed,the coning angle of the convergent film gap is enlarged,the temperature rises and leakage rate increases,while the frictional torque decreases.The proposed fluid-solid thermal and mechanical coupling model can be applied for the optimization design of ultra high-speed mechanical seal for turbopump.