高转速袋型阻尼密封泄漏的特性

采用有限元分析和计算流体动力学耦合数值分析方法（FEA/CFD）,研究了考虑转子系统由于高速旋转造成转子径向伸长效应时袋型阻尼密封的泄漏特性和流场形态.计算了密封间隙为0.13mm时,袋型阻尼密封试验件在3种压比、3种转速下的泄漏量,并与试验值和不考虑转子伸长效应的CFD数值模拟结果进行了比较,验证了所采用的FEA/CFD数值方法的可靠性（误差小于1.3%）和高转速下考虑转子伸长的必要性.研究了6种压比、6种转速下密封间隙为0.25mm的袋型阻尼密封的流场和泄漏量,分析了压比和转速对袋型阻尼密封泄漏特性的影响规律.结果表明：当压比大于0.26时,随压比的减小,袋型阻尼密封泄漏量逐渐增大;当压比减小到一定值时（π〈0.26）,泄漏流体的马赫数在最后一个密封齿间隙处达到1.0,即发生了堵塞,此时泄漏量达到与密封进口总压相对应的最大值;在高转速下,考虑和不考虑转子半径的伸长,密封泄漏量均随转速的增大而减小;在转子面周向马赫数大于0.35时,需要考虑转子半径伸长对泄漏量的影响.

Leakage flow of pocket damper seal at high rotational speed

The leakage flow characteristics of the pocket damper seal(PDS) was numerical investigated with consideration of the rotor growth effect at the high rotational speed using finite element analysis/computational fluid dynamics(FEA/CFD).The leakage flow rate of the experimental pocket damper seal with 0.13mm clearance at three different pressure ratios and three different rotational speeds was conducted.The accuracy of the present numerical approach was demonstrated by comparison of the experimental data and numerical results without consideration of rotor growth.Six pressure ratios and six rotational speeds were utilized to analyze the leakage flow characteristics of the pocket damper seal.The influence of the higher pressure and higher rotational speed on the leakage flow characteristics of the pocket damper seal was analyzed.The obtained results show that for pressure ratio down to 0.26, the leakage flow rate of the pocket damper seal increases with the decreasing pressure ratio.The leakage flow rate of the pocket damper seal obtains the maximum value when the pressure ratio equals to 0.26.The Mach number of the leakage flow obtains 1 at the last fin clearance when the pressure ratio is 0.26.At the higher rotational speed, the leakage flow rate of the pocket damper seal decreases with the increasing rotational speed with and without consideration of the rotor growth effects.The rotor growth effect should be taken into account to predict the leakage flow rate of the pocket damper seal when Mach number exceeds 0.35.