共查询到17条相似文献,搜索用时 93 毫秒
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迷宫密封动力特性影响因素分析 总被引:3,自引:0,他引:3
迷宫密封的存在会引起汽流激振,密封的结构和工况参数对转子动力特性均存在影响。本文综合分析转子转速、入口预旋比、密封间隙、压差等因素对转子动力特性系数的影响,为迷宫密封汽流激振的防治和设计中各参数的最优确定提供参考依据。 相似文献
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超超临界汽轮机转子密封激振特性研究 总被引:1,自引:0,他引:1
考虑非线性密封激振力、可倾瓦轴承的弹性支承力、转子阻尼力、转子不平衡力与重力,建立超超临界600MW汽轮机高中压转子-密封系统的非线性动力学模型。该非线性转子-密封系统动力学方程组具有超大规模的维数,采用Newmark数值积分方法对其进行求解,模拟出运行在正常工况下与最大工况下转子不平衡响应与汽流激振的特性;对转子不平衡量和密封流体的周向平均流速对汽流激振现象的影响规律进行分析。结果表明:在一定的范围内,不平衡量大小对发生汽流激振的失稳转速影响很小;密封内流体周向平均速比是影响汽流激振的失稳转速的主要因素,适当减小密封内流体周向平均速比可提高汽流激振的失稳转速;超超临界机组运行在最大工况下高中压转子发生汽流激振的失稳转速明显低于正常工况下的失稳转速。 相似文献
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随着旋转机械结构参数的提高,作用在转子上的密封中的气流激振力将显著增大。本文针对裂纹转子密封系统进行了研究。应用Muszynska非线性密封力模型,建立了在密封中的气流激振力作用下的裂纹转子系统耦合动力学方程,分析了在非线性密封力作用下的裂纹转子运动特性,并着重讨论了迷宫密封的物理和结构参数对裂纹转子运动特性的影响。研究结果表明,系统具有非常丰富的非线性动力学行为,密封中的气流激振力对裂纹转子的周期运动有明显的抑制作用,密封结构的各主要参数对系统稳定性有很大影响,故可以通过调整密封参数来改善系统的动态稳定性,这为旋转机械的理论设计和故障动态监测提供了理论依据。 相似文献
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非线性转子-机匣密封碰摩系统的耦合振动分析 总被引:1,自引:0,他引:1
随着旋转机械结构参数的提高,作用在转子上的气流激振力将显著增大.针对转子-机匣密封碰摩系统进行了研究.应用MuSzynska非线性密封力模型,建立了在气流激振力作用下的转子-机匣碰摩系统耦合动力学方程,分析了在非线性密封力作用下的碰摩转子运动特性.着重讨论了迷宫密封的物理和结构参数对碰摩转子运动特性的影响.研究结果表明,系统具有非常丰富的非线性动力学行为,气流激振力对碰摩转子的准周期运动有明显的抑制作用,密封结构的各主要参数对系统稳定性有很大影响,可以通过调整密封参数来改善系统的动态稳定性.为旋转机械的理论设计和故障动态监测提供了依据. 相似文献
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迷宫密封的气流激振是大型透平机组发生失稳的一个重要原因。评价转子系统稳定性的主要在数之一便是动力特性系数。对迷宫密封的动力特性系数提出了一种新的理论计算方法,理论计算与实验结果之间吻合良好。通过分析各有关参数对动力特性系数的影响,为迷宫密封气流激振的防治提供了对策。 相似文献
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ANALYSIS OF COUPLING INFLUENCES OF LABYRINTH SEAL PARAMETERS ON CROSS COUPLED STIFFNESS AND DIRECT DAMPING COEFFICIENT 总被引:1,自引:0,他引:1
A~ndal area Of cODtIDI volume (Inlnz )b~Breadth Of tOP of teeth(rnm)C, c--Damping (N' slm)e--Eccentricity~force(N)fi,fz--Coefficient of inchon factorC, X, Y--Constantsh~Height of teeth (mzn)K, k--S~s (N/m)L~ length Of seal cavihes (mxn)Li~Pitch (nun).m--~ mass flow (kg' m- 1' s- I )Nc--N~ Of seal cavihesnl --Circular speed Of ~ (r/ndn)nZ--ROtor speed (rlndn)p~Dess~ (Pa)p,--Dessme ~nce (Pa)R~Gas constant (J' kg~ l' K~ I )R,~ndus Of contIDI VOlume 1 (nun)RZ~ndus Of contIDI… 相似文献
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CFD Study on Stepped and Drum Balance Labyrinth Seal 总被引:2,自引:0,他引:2
The stability of rotors in turbomachines is affected by the labyrinth seal where driving forces are generated. Recent research results have shown that the preswirl has a significant influence on the rotordynamic characteristics of the straight labyrinth seal including both tooth-on-stator and tooth-on-rotor configurations. However, modern turbomachines require higher and higher pressure drop for the seal so that the eye seal is usually designed as stepped labyrinth, whereas the balance drum usually employs a tooth-interlocking labyrinth and a larger number of teeth. Both designs could generate greater forces on the rotor than the straight labyrinth seal. Therefore, it is necessary to further study the influence of preswirl on stepped and tooth-interlocking labyrinth seals. This article employed 3D calculational fluid dynamics (CFD) to solve the flow in those seals. Then the rotordynamic coefficients of the two seals at different preswirl rates were calculated based on the CFD results. The results were compared with test data and bulk flow results. A rotor stability analysis was conducted considering the balance drum seal with the coefficients predicted by the numerical method. 相似文献
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针对现场实测振动数据表明转轴-可倾瓦-密封系统存在的振动失稳问题,从可倾瓦参数的理论模型、汽流激振力、进汽方式、运行参数、轴承载荷、安装工艺等角度分析转轴-可倾瓦-密封系统振动失稳的原因,并深入讨论转轴-可倾瓦-密封系统振动稳定裕度问题,提出用对数衰减率、系统阻尼、系统抗定常干扰界限值来描述系统的稳定性。 相似文献
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提出一种密封入口周向均匀设置有涡流槽的新型密封结构,建立了传统迷宫密封与新型涡流槽密封泄漏特性及动力特性求解模型,在实验验证数值计算方法准确性的基础上,通过比较分析了传统迷宫密封与新型涡流槽密封在不同进出口压比、预旋比工况下的泄漏特性与动力特性,研究了新型涡流槽结构对密封泄漏特性及动力特性的影响机理。研究结果表明:随着涡流槽数量的增加,涡流槽密封的泄漏量逐渐降低;在同一压比下,不同涡流槽数新型密封的泄漏量之间差值随着压比的增大而增大。当压比为6时,64涡流槽的新型密封较传统迷宫密封,泄漏量下降了3.37%;在高预旋比的工况下,不同涡流槽数量密封的切向气流力均与转子涡动方向相反,起到抑制转子涡动的作用,且随着涡流槽数量的增加,切向气流力也随着增大;随着转子涡动频率的增大,三种不同涡流槽数量密封的交叉刚度先减小到负值然后增大到正值。涡流槽密封的有效阻尼均高于传统迷宫密封,新型涡流槽密封可以提高转子系统的稳定性。 相似文献
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分析了密封装置激起转子失稳的机理,在此基础上,得出了转子失稳的条件以及失稳边界,即失稳发生在转子工作转速大于2倍转子临界转速的条件下之下。根据密封装置对转子刚度和阻尼的影响规律,提出了消除此类故障的措施。 相似文献
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Xin Yan Xinbo Dai Kang Zhang Jun Li Kun He 《Journal of Mechanical Science and Technology》2018,32(10):4697-4709
To achieve higher aerodynamic performance, turbine usually works at tight clearance, which results in inevitable rub between the rotor and stator parts of labyrinth seal due to vibrations, misalignment, mechanical force, thermal stress, etc. In the rubbing events, contact between labyrinth fin and rotor part will commonly induce the teeth bending and mushrooming damages, which significantly affect the discharge performance of a labyrinth seal. To account for the influence of teeth bending and mushrooming on leakage performance of a straight-through labyrinth seal, the leakage rates and flow fields in the worn labyrinth seal are measured and also compared with the original design cases. With numerical methods, the discharge behaviors of the labyrinth seal with different degrees of bending and mushroom damages are analyzed. It shows that the predicted leakage performance and flow fields in the labyrinth seals match well with the experimental tests. For the bending cases, the leakage rates and flow patterns in labyrinth seals are dependent on the effective clearance and bending angle. The leakage ratio of forward bending case is smaller than that of backward bending case with the same geometrical dimensions. However, for the mushroomed labyrinth seals, the leakage rates and flow patterns are much dependent on the effective clearance but slightly dependent on the mushroom radius. 相似文献