进口防旋板对孔型密封非定常气流激振特性的影响
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摘要
为了展示透平机械密封系统设计中进口防旋板在改善密封转子动力特性和增强转子系统稳定性的止旋方面的性能,采用基于转子多频椭圆轨迹涡动模型和动网格技术的非定常数值方法,研究了进口防旋板对孔型密封非定常气流激振力和转子动力特性系数的影响,计算分析了进口预旋比分别为0和0.6时2种进口防旋板结构的孔型密封转子动力特性系数、非定常气流激振力和流场特性,并与实验结果进行了对比。研究表明:非定常数值方法能够准确预测与频率相关的孔型密封转子动力特性系数;进口预旋可显著减小孔型密封的有效阻尼、增大有效阻尼项的穿越频率,易诱发转子涡动失稳;进口防旋板能够有效减小孔型密封的进口旋流速度、孔型密封的交叉刚度和有效阻尼穿越频率,增大孔型密封的有效刚度和有效阻尼,进而提高转子系统的稳定性。
To reveal the anti-swirl performance of the swirl brake on improving the seal rotordynamic performance and enhancing rotor stability in turbomachinery,the effects of swirl brakes on the transient flow excitation characteristics and rotordynamic coefficients of a holepattern seal are numerically investigated.With computational fluid dynamics(CFD)method based on the multi-frequency elliptical orbit rotor whirling model and mesh deformation technique,the rotordynamic coefficients,transient fluid response forces and flow pattern of the hole-pattern seal are solved and analyzed for two types of swirl brakes at inlet preswirl ratios of 0 and 0.6.The predicted rotordynamic coefficients are compared with the experiment data.The numerical results show that the present transient numerical method enables to accurately predict the frequency-dependent rotordynamic coefficients of hole-pattern seal.Inlet preswirl significantly decreases effective damping in the hole-pattern seal and increases in the crossover frequency of the effective damping term,which usually induces rotor instability vibration.The swirl brake is very useful to eliminate rotor instability vibration because it can obviously reduce the cross-coupling stiffness and the crossover frequency,and increase the hole-pattern seal effective stiffness andeffective damping by reducing the inlet preswirl velocity.
To reveal the anti-swirl performance of the swirl brake on improving the seal rotordynamic performance and enhancing rotor stability in turbomachinery,the effects of swirl brakes on the transient flow excitation characteristics and rotordynamic coefficients of a holepattern seal are numerically investigated.With computational fluid dynamics(CFD)method based on the multi-frequency elliptical orbit rotor whirling model and mesh deformation technique,the rotordynamic coefficients,transient fluid response forces and flow pattern of the hole-pattern seal are solved and analyzed for two types of swirl brakes at inlet preswirl ratios of 0 and 0.6.The predicted rotordynamic coefficients are compared with the experiment data.The numerical results show that the present transient numerical method enables to accurately predict the frequency-dependent rotordynamic coefficients of hole-pattern seal.Inlet preswirl significantly decreases effective damping in the hole-pattern seal and increases in the crossover frequency of the effective damping term,which usually induces rotor instability vibration.The swirl brake is very useful to eliminate rotor instability vibration because it can obviously reduce the cross-coupling stiffness and the crossover frequency,and increase the hole-pattern seal effective stiffness andeffective damping by reducing the inlet preswirl velocity.
引文
[1]VANCE J M.Machinery vibration and rotordynamics[M].New York,USA:John Wiley&Sons,2010:271-272.
[2]CHILDS D W,VANCE J M.Annular seals as tools to control rotor dynamic response of future gas turbine engines,AIAA 94-2804[R].Reston,VA,USA:AIAA,1994.
[3]LI J,CHOUDHURY P D,KUSHNER F.Evaluation of centrifugal compressor stability margin and investigation of antiswirl mechanism[C]∥Proceeding of the32nd Turbomachinery Symposium.Texas,USA:Texas A&M University,2003:49-57.
[4]BENCKERT H,WACHTER J.Flow induced spring coefficients of labyrinth seals for application in rotordynamics[C]∥Proceedings of a Workshop on Rotordynamic Instability Problems in High-Performance Turbomachinery.Texas,USA:Texas A&M University,1980:189-212.
[5]CHILDS D W,RAMSEY C.Seal rotordynamic coefficient test results for a model SSME ATD-HPFTP turbine interstage seal with and without a swirl brake[J].ASME Journal of Tribology,1991,113(1):198-203.
[6]CHILDS D W,MCLEAN J E,ZHANG M,et al.Rotordynamic performance of a negative-swirl brake for a tooth-on-stator labyrinth seal,GT2014-25577[R].New York,USA:ASME,2014.
[7]NIELSON K K,CHILDS D W,MYLLERUP C M.Experimental and theoretical comparison of two swirl brake designs[J].ASME Journal of Turbomachinery,2001,123(2):353-358.
[8]SCHARRER J.Test results for leakage and rotordynamic coefficients;comparisons to labyrinth and smooth configurations[J].ASME Journal of Triboloby,1989,111(2):300-301.
[9]ZEIDAN F Y,PEREZ R X,STEPHENSON E M.The use of honeycomb seals in stabilizing two centrifugal compressors[C]∥Proceedings of 22nd Turbomachinery Symposium,Turbomachinery Laboratory.Texas,USA:Texas A&M University,1993:3-15.
[10]CHILDS D W,WADE J.Rotordynamic-coefficient and leakage characteristics for hole-pattern-stator annular gas seals-measurements versus predictions[J].ASME Journal of Tribology,2004,126(2):326-333.
[11]BROWN P,CHILDS D.Measurement versus predictions of rotordynamic coefficients of a hole-pattern gas seal with negative preswirl[J].ASME Journal of Engineering for Gas Turbines and Power,2012,134(12):122503.
[12]晏鑫,李军,丰镇平.BULK FLOW方法分析孔型密封转子动力特性的有效性[J].西安交通大学学报,2009,43(1):24-28.YAN Xin,LI Jun,FENG Zhenping.Validation of two-control-volume BULK FLOW method for rotordynamic characteristics of hole-pattern seals[J].Journal of Xi’an Jiaotong University,2009,43(1):24-28.
[13]YAN X,LI J,FENG Z.Investigations on the rotordynamic characteristics of a hole-pattern seal using transient CFD and periodic circular orbit model[J].ASME Journal of Vibration and Acoustics,2011,133(4):041007.
[14]李志刚,李军,丰镇平.袋型阻尼密封转子动力特性的多频单向涡动预测模型[J].西安交通大学学报,2012,46(5):13-18.LI Zhigang,LI Jun,FENG Zhenping.Multiple frequencies one-dimensional prediction model of rotordynamic characteristics for pocket damper seals[J].Journal of Xi’an Jiaotong University,2012,46(5):13-18.
[15]LI Zhigang,LI Jun,YAN Xin.Multiple frequencies elliptical whirling orbit model and transient RANS solution approach to rotordynamic coefficients of annual gas seals prediction[J].ASME Journal of Vibration and Acoustics,2013,135(3):031005.
[2]CHILDS D W,VANCE J M.Annular seals as tools to control rotor dynamic response of future gas turbine engines,AIAA 94-2804[R].Reston,VA,USA:AIAA,1994.
[3]LI J,CHOUDHURY P D,KUSHNER F.Evaluation of centrifugal compressor stability margin and investigation of antiswirl mechanism[C]∥Proceeding of the32nd Turbomachinery Symposium.Texas,USA:Texas A&M University,2003:49-57.
[4]BENCKERT H,WACHTER J.Flow induced spring coefficients of labyrinth seals for application in rotordynamics[C]∥Proceedings of a Workshop on Rotordynamic Instability Problems in High-Performance Turbomachinery.Texas,USA:Texas A&M University,1980:189-212.
[5]CHILDS D W,RAMSEY C.Seal rotordynamic coefficient test results for a model SSME ATD-HPFTP turbine interstage seal with and without a swirl brake[J].ASME Journal of Tribology,1991,113(1):198-203.
[6]CHILDS D W,MCLEAN J E,ZHANG M,et al.Rotordynamic performance of a negative-swirl brake for a tooth-on-stator labyrinth seal,GT2014-25577[R].New York,USA:ASME,2014.
[7]NIELSON K K,CHILDS D W,MYLLERUP C M.Experimental and theoretical comparison of two swirl brake designs[J].ASME Journal of Turbomachinery,2001,123(2):353-358.
[8]SCHARRER J.Test results for leakage and rotordynamic coefficients;comparisons to labyrinth and smooth configurations[J].ASME Journal of Triboloby,1989,111(2):300-301.
[9]ZEIDAN F Y,PEREZ R X,STEPHENSON E M.The use of honeycomb seals in stabilizing two centrifugal compressors[C]∥Proceedings of 22nd Turbomachinery Symposium,Turbomachinery Laboratory.Texas,USA:Texas A&M University,1993:3-15.
[10]CHILDS D W,WADE J.Rotordynamic-coefficient and leakage characteristics for hole-pattern-stator annular gas seals-measurements versus predictions[J].ASME Journal of Tribology,2004,126(2):326-333.
[11]BROWN P,CHILDS D.Measurement versus predictions of rotordynamic coefficients of a hole-pattern gas seal with negative preswirl[J].ASME Journal of Engineering for Gas Turbines and Power,2012,134(12):122503.
[12]晏鑫,李军,丰镇平.BULK FLOW方法分析孔型密封转子动力特性的有效性[J].西安交通大学学报,2009,43(1):24-28.YAN Xin,LI Jun,FENG Zhenping.Validation of two-control-volume BULK FLOW method for rotordynamic characteristics of hole-pattern seals[J].Journal of Xi’an Jiaotong University,2009,43(1):24-28.
[13]YAN X,LI J,FENG Z.Investigations on the rotordynamic characteristics of a hole-pattern seal using transient CFD and periodic circular orbit model[J].ASME Journal of Vibration and Acoustics,2011,133(4):041007.
[14]李志刚,李军,丰镇平.袋型阻尼密封转子动力特性的多频单向涡动预测模型[J].西安交通大学学报,2012,46(5):13-18.LI Zhigang,LI Jun,FENG Zhenping.Multiple frequencies one-dimensional prediction model of rotordynamic characteristics for pocket damper seals[J].Journal of Xi’an Jiaotong University,2012,46(5):13-18.
[15]LI Zhigang,LI Jun,YAN Xin.Multiple frequencies elliptical whirling orbit model and transient RANS solution approach to rotordynamic coefficients of annual gas seals prediction[J].ASME Journal of Vibration and Acoustics,2013,135(3):031005.