锥度和不对中误差对止推箔片轴承承载特性的影响

Influence of Taper and Misalignment Errors on Load Characteristics of Thrust Foil Bearings

空间核电系统采用高温气冷堆闭式布雷顿循环方案,使动力转换系统可高效地利用核能发电。动力转换系统采用止推箔片轴承,省略了供油和供气系统。建立柱坐标系下可压缩气体的雷诺方程并耦合求解锥度和不对中误差影响的气膜厚度方程,分析了止推箔片轴承在生产和装配过程中产生的锥度和不对中误差对轴承承载特性的影响。结果表明:在设计间隙不变的情况下,锥度增大导致轴承承载力减小;在轴向载荷恒定的情况下,锥度绝对值越大,最小气膜厚度越小,最大气膜压力则相反;随着不对中角度增加,轴承承载力和摩擦功快速增大,单瓦的承载力出现严重不均衡情况,不对中误差对轴承刚度系数和阻尼系数的影响较明显,直接影响转子系统的稳定性。

The closed Brayton cycle scheme of high-temperature gas-cooled reactor is adopted in space nuclear power system,so that the power conversion system can use nuclear energy to generate power more efficiently.The power conversion system adopts thrust foil bearings,omitting the oil supply and gas supply systems.The Reynolds equation of compressible gas in a cylindrical coordinate system is established,and the gas film thickness equation affected by taper and misalignment errors is solved by coupling.The influence of taper and misalignment errors generated during production and assembly of the bearings on load characteristics is analyzed.The results show that:under the condition of constant design clearance,the increase of taper leads to decrease of bearing load capacity;under the condition of constant axial load,the larger the absolute value of taper,the smaller the minimum gas film thickness,and the larger the maximum gas film pressure;with the increase of misalignment angle,the load capacity and friction work of the bearings increase rapidly,and the load capacity of single pad is seriously unbalanced,the misalignment errors have obvious influence on stiffness coefficient and damping coefficient of the bearings,affecting the stability of rotor system directly.