中文摘要：

基于多频椭圆涡动模型和动网格技术,通过数值求解三维非定常Reynolds-Averaged Navier-Stokes（RANS）方程和κ-ε紊流模型的方法,研究了进口预旋和涡动频率对旋转动密封转子动力特性的影响。研究表明：旋转动密封在x和y方向具有相同的直接激振力系数（K_（xx）≈K_（yy）,C_（xx）≈C_（yy））和大小相等、符号相反的交叉激振力系数（K_（xy）≈-K_（yx）,C_（xy）≈-C_（yx））;旋转动密封具有正的、频率无关的直接刚度系数,其值随进口预旋的增大而增大。进口预旋对密封交叉刚度的大小和符号均具有显著影响;直接阻尼系数在低频区为负值,且随涡动频率的增大而增大,在90 Hz附近变为正值;在整个涡动频率范围内,旋转动密封的有效阻尼均为负值,不利于转子系统的稳定,其产生的流体激振力可能诱发转子系统失稳。进口预旋虽在一定程度上减小了正的交叉刚度,但同时增大了负的直接阻尼,最终使密封有效阻尼减小;较大的进口预旋增大了转子系统失稳的风险。

英文摘要：

Based on multi-frequency elliptical whirling orbit model and mesh deformation technique,three-dimension transient Reynolds-Averaged Navier-Stokes（RANS） solution methods and κ — εturbulent model are employed to investigate the influences of inlet preswirl and whirling frequency on the rotordynamic characteristics of rotating seals.Numerical results show that the rotating seal possesses the same direct force coefficients（K_（xx） ≈ K_（yy）,C_（xx） ≈ C（yy）） and equal-value,opposite-sign cross-coupling force coefficients（K（xy） ≈ — K（yx）,C（xy）≈-C（yx））;The rotating seal possesses positive,frequency-independent direct stiffness coefficients which increase with the increasing inlet preswirl;The increasing inlet preswirl has a significant effect on the magnitude of cross-coupling stiffness as well as the sign;The rotating seal possesses negative direct damping at lower frequencies whose value increases with the increasing whirling frequency and cross over to positive value at around 90 Hz;The rotating seal possesses negative effective damping throughout the whole frequency range,which is undesired for the rotor system stability and may generate destabilizing fluid excitation forces inducing rotor instability;The increasing inlet preswirl results in a decrease in the effective damping due to the combination of decreasing positive cross-coupling stiffness and increasing negative direct damping;The larger inlet preswirl results in an increasing risk of rotor instability.