双向旋转槽型干气密封性能分析

发布时间：2018-03-25 01:34

本文选题：仿枫叶槽　切入点：干气密封　出处：《昆明理工大学》2017年硕士论文

【摘要】：螺旋槽干气密封(S-DGS)因具有良好的动压效应、较强的抗干扰能力,应用较为广泛。但在实际生产中,由于操作失误或异常停机事故会导致设备反向旋转,从而密封失效的生产事故发生。双向旋转密封则可较好的解决该问题。目前,国内外研究人员对于双向旋转式干气密封密封特性进行了相关的研究,虽然取得了一些进展,但仍存在低速运转开启力不足等问题。为了获得更好的双向旋转槽型密封特性,本文作者基于干气密封技术和仿生学原理提出一种新型的双向旋转式干气密封槽型,并对其密封性能进行研究。主要的研究如下:利用Fluent对仿枫叶槽干气密封流场进行数值模拟,分别考察了不同气膜厚度和不同操作条件对密封性能的影响,结果表明:膜厚ho分别为2.03μm、3.05μm、5.08μm时,仿枫叶槽干气密封均能具有稳定的动压效应,在同一槽深下,动压效应会随气膜厚度的增加而减弱;膜厚ho=2.03μm时,开启力和泄漏率均随操作压力的增大而增加,且开启力的增幅更大。当槽深大于11μm后,与螺旋槽干气密封相比,仿枫叶槽具有更大的开启力;当槽深为5μm时,气膜厚度在3～5μm时,仿枫叶槽相比于螺旋槽具有更好的抗干扰能力。利用Fluent数值模拟分析了实际气体效应对螺旋槽、槽底倾斜螺旋槽、仿枫叶槽干气密封性能的影响。研究结果表明,槽底倾斜相比于普通螺旋槽具有更大的轴向刚度。实际气体效应对于干气密封的泄漏率有较大影响,对于气膜开启力的影响不大。空气和氮气在理想气体状态的结果和实际气体的结果相差不大,由于氢气相比空气、氮气更难压缩,氢气实际气体的结果均小于理想气体的结果。实际气体效应对槽区温度没有太大影响。仿枫叶槽靠近外径处的气体温度较低,当膜厚的增加,气膜的高温区由台区逐渐转移到密封坝区。膜厚越大,端面气膜的平均温度越低。假设静环变形是轴对称线性变形,将气膜压力与静环变形进行耦合分析,采用皮采诺圆环理论计算公式,对静环的变形量解析计算,结果表明,密封间隙越小,静环变形量越大。利用ANSYS Workbench平台联合Fluent和Mechanical软件对仿枫叶槽干气密封进行流固耦合数值模拟,并将数值模拟的结果与解析计算的结果进行对比验证,结果表明,数值模拟的结果与解析计算的结果相差不是特别大,静环最大变形量主要发生在静环外径处。
[Abstract]:The spiral groove dry gas seal S-DGSs is widely used because of its good dynamic pressure effect and strong anti-interference ability. However, in actual production, the equipment will rotate in reverse because of operation error or abnormal shutdown accident. Thus, the production accident of seal failure occurs. Bidirectional rotary seal can solve this problem better. At present, researchers at home and abroad have carried out relevant research on the characteristics of bidirectional rotary dry gas seal, although some progress has been made. However, there are still some problems such as insufficient opening force in low speed operation. In order to obtain better sealing characteristics of bidirectional rotary groove, a new type of bidirectional rotary dry gas seal groove is proposed based on dry gas seal technology and bionic principle. The main results are as follows: numerical simulation of dry gas seal flow field in maple blade grooves was carried out by Fluent, and the effects of different film thickness and operation conditions on seal performance were investigated respectively. The results show that when the film thickness ho is 2.03 渭 m ~ 3.05 渭 m ~ 5.08 渭 m, the dynamic pressure effect of dry gas seal in maple blade trough is stable, and the dynamic pressure effect decreases with the increase of film thickness under the same groove depth, and when the film thickness is ho=2.03 渭 m, the dynamic pressure effect decreases with the increase of film thickness. Both the opening force and leakage rate increased with the increase of operating pressure, and the opening force increased more. When the groove depth was more than 11 渭 m, the simulated maple blade groove had a greater opening force than the spiral groove dry gas seal, and when the groove depth was 5 渭 m, the film thickness was 3 渭 m. Compared with the spiral groove, the simulated maple blade groove has better anti-interference ability. The effect of the actual gas effect on the helical groove, the inclined spiral groove at the bottom of the groove and the dry gas seal performance of the simulated maple blade groove is analyzed by Fluent numerical simulation. The results show that, The inclination of the bottom of the groove has greater axial stiffness than that of the common spiral groove. The actual gas effect has a great effect on the leakage rate of the dry gas seal. The result of air and nitrogen in ideal gas state is not different from that of real gas, because hydrogen is more difficult to compress nitrogen than air. The results of the actual hydrogen gas are smaller than those of the ideal gas. The actual gas effect has no great effect on the temperature of the trough. The temperature of the gas near the outer diameter of the maple leaf trough is lower than that of the ideal gas, and when the film thickness increases, The higher the film thickness, the lower the average temperature of the gas film. Assuming that the static ring deformation is axisymmetric linear deformation, the film pressure is coupled with the static ring deformation. The deformation of the static ring is calculated analytically by using the theoretical formula of Piczeno ring. The result shows that the smaller the seal clearance, the smaller the seal clearance. The larger the deformation of static ring is, the more numerical simulation of fluid-solid coupling is carried out by using ANSYS Workbench platform combined with Fluent and Mechanical software, and the results of numerical simulation are compared with those of analytical calculation. The result of numerical simulation is not especially different from that of analytical calculation. The maximum deformation of static ring mainly occurs at the outside diameter of static ring.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TH136

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