高速干气密封端面型槽仿生设计理论与实验研究

发布时间：2018-01-22 00:37

  本文关键词： 干气密封 高速 仿生设计 鸟翼 稳定性　出处：《浙江工业大学》2016年博士论文　论文类型：学位论文

【摘要】：离心压缩机用于气体的压缩和输送,是石油化工、能源输运等行业中的“心脏”设备。随着离心压缩机向大轴径、高速、高压等高参数方向发展,干气密封易遭受气膜失稳、磨损和端面变形等威胁,严重影响压缩机乃至整个生产装置的正常运行。我国“十二五”规划中也明确提出要重点发展大型压缩机高可靠性机械密封装置和高性能非接触式机械密封。可见,研究开发大型高速压缩机用高性能、高可靠性干气密封,并实现完全自主知识产权,对于保证高速压缩机的长周期稳定运行乃至我国的能源安全具有重要的实际意义和战略意义。从高速飞鸟翼翅宏观构形和羽翼结构两个层面出发,建立了典型高速飞鸟的多元耦合递阶层次结构模型;基于工程仿生学方法,提出并构建了干气密封典型仿鸟翼形端面型槽的几何模型和参数体系;基于统计学方法分析了飞鸟翼翅外形轮廓与干气密封端面型槽之间的关联规律,论证了基于飞鸟翼翅外形的端面型槽仿生的可行性和有效性。建立干气密封端面型槽稳态密封性能分析的数学模型,基于完全析因设计方法,获得了干气密封螺旋槽关键结构参数的优选值,为后续仿生型槽的性能对比分析提供统一对比基准。提出压缩数压力比这一综合表征工况条件的特征参数,在此基础上发明并优选出集束仿生槽和微列仿生槽两种综合密封性能优异的典型仿生型槽。通过对高速条件下上述两种典型仿生型槽干气密封端面压力场和速度场的数值模拟仿真分析,揭示了典型仿生型槽在高速条件下能保持较低泄漏率的同时显著提升气膜刚度的作用机理,获得了关键几何结构参数对典型仿生型槽干气密封性能的影响规律,给出了上述结构参数的优选值范围。为验证数值分析结果,自主搭建了弹簧比压可调、气膜厚度和泄漏率可测的高速干气密封实验装置,提出一种测量干气密封端面气膜刚度的新方法,实验测试了典型仿生型槽干气密封在静压条件和高速低压条件下的密封性能,分析了关键结构参数和工况参数对其密封性能的影响规律。结果表明,与普通螺旋槽相比,典型仿生型槽在高速低压条件下的气膜刚度提升20%~50%,泄漏率降低20%~40%,是两种综合密封性能优异的端面型槽结构;槽深、介质压力和弹簧比压等参数对干气密封性能影响明显。基于微扰法和有限差分法,考虑轴向扰动建立干气密封气膜动态特性分析数学模型,推导出表征气膜轴向动态特性的刚度系数和阻尼系数计算表达式,并通过与文献值的结果对比验证了程序和数值分析方法的正确性。借鉴高速飞鸟翼翅的收敛构形,对比分析了普通螺旋槽和典型收敛型槽两类干气密封的气膜动态特性,指出收敛型槽能显著提升密封低频扰动下的阻尼特性,从而避免自激振动发生。对比分析了典型仿生型槽干气密封的轴向气膜动态特性,研究了关键几何结构参数对其气膜动态特性的影响规律,结果表明典型仿生型槽在高频扰动时具有更佳的阻尼特性,而在低频扰动时刚度特性更佳,且型槽结构参数对气膜动态特性的影响显著。基于压缩数压力比这一特征参数提出一种快速判断典型仿生型槽适用工况范围的型槽选型新方法,给出了典型仿生型槽性能参数增量比与压缩数压力比的拟合表达式。借鉴离心泵选型型谱图,提出不同工况条件下典型仿生型槽关键几何结构参数的优选型谱图,以解决型槽结构参数优选值随工况条件而变化导致无法正确选型和定型的问题,为仿鸟翼形端面型槽干气密封的工程选型与优化设计提供指导。论文的研究成果较系统地提出了高速干气密封端面型槽仿生设计的理论与方法,可为大型高速旋转机械用高性能干气密封的工程选型与优化设计提供理论依据。
[Abstract]:Centrifugal compressor for compressing and conveying gas, petrochemical, energy, transport and other industries in the "heart". With the centrifugal compressor to large diameter, high speed, high pressure and high parameter direction, dry gas seal is vulnerable to gas film instability, wear and deformation of face threat seriously affects the normal operation of the compressor and the whole production equipment. China's "12th Five-Year" plan also explicitly proposed to focus on the development of large-scale compressor high reliability of mechanical seal and non-contact mechanical seal device and high performance. Therefore, research and development of large-scale high-speed compressor with high performance, high reliability of the dry gas seal, and to achieve a completely independent intellectual property rights, it is important to ensure practical significance and strategic significance of long period stable operation of high speed compressor and the energy security of our country. From the macro configuration and high speed bird wing wing structure of the two layer of, Establishment of a multi coupled hierarchical structure model of typical high-speed birds; bionics method based on geometric model is proposed and the parameter system of dry gas seal face groove shape with typical imitation; based on the statistical analysis of the bird wing shape and dry gas seal association rules between face groove, demonstrates the feasibility of the end groove shape of the wings of birds bionic and effectiveness. Based on mathematical model analysis of seal groove dry gas seal steady-state performance, full factorial design method based on optimal selection of dry gas key structural parameters of spiral groove seal value, provide a unified benchmark for performance comparison analysis. Subsequent bionic groove feature the number of compression pressure ratio parameters are put forward a comprehensive characterization of working conditions, on the basis of the invention and the selection of cluster bionic groove and two kinds of micro column bionic groove density comprehensive The typical bionic groove sealing properties. Through dry gas of high speed under the conditions of the two typical bionic groove seal numerical simulating analysis of velocity field and pressure field of face, reveal the typical bionic groove can keep a low leakage rate and significantly improve the mechanism of gas film stiffness in the condition of high speed the influence of key geometrical parameters of typical bionic groove dry gas seal performance, optimization of the structure parameters is given value. In order to verify the results of numerical analysis, we build a spring pressure adjustable, film thickness and leakage rate can be measured in high speed dry gas seal test device, puts forward a new method for measurement of dry gas seal gas film stiffness, tested the seal performance in static condition and high speed under low pressure conditions typical of bionic groove dry gas, analyzes the key structure parameters and operating parameters on the density Influence of sealing performance. The results show that compared with the ordinary spiral groove gas film in high speed under low pressure conditions typical bionic groove stiffness to improve 20%~50%, reduce leakage rate of 20%~40%, is the two comprehensive seal groove structure excellent performance; groove depth, medium pressure and spring pressure parameters of dry gas the sealing performance is obvious. The perturbation method and the finite difference method based on the establishment of stem axial perturbation analysis mathematical model of dynamic characteristics of gas film seal, calculation formula of stiffness coefficient and damping coefficient deduced the axial dynamic characterization of gas film, and by comparison with literature values of the results verify the correctness of the program and numerical analysis methods. From the configuration of high speed convergence bird wings, comparative analysis of the dynamic characteristics of ordinary gas film spiral groove and groove of two kinds of typical convergence of dry gas seal, pointed out that the convergence groove can significantly improve the sealing of low frequency disturbance The damping characteristic, so as to avoid the occurrence of self-excited vibration. Comparative analysis of the dynamic characteristics of the axial gas film typical bionic groove dry gas seal, studied the key geometric structural parameters on the dynamic behavior of gas film. The results show that the typical bionic groove with better damping characteristics in high frequency disturbance, and in low frequency when the disturbance of stiffness is better, and the parameter type groove structure influence on the dynamic characteristics of the gas film is significant. The number of compression pressure ratio characteristic parameters and proposes a rapid new method to determine the range of applicable conditions of typical groove type bionic groove based on the fitted parameters of typical bionic groove performance increment ratio and compression pressure ratio the reference spectrum is presented. Selection of a centrifugal pump type, spectrum optimization type proposed key parameters of geometric structure of typical bionic groove under different conditions, in order to solve the optimization of structure parameters of groove with condition The conditions can lead to the correct selection and setting of the problem, provide guidance for engineering selection and optimization design of gas seal for imitation bird shaped face groove. The research results of the thesis systematically puts forward the theory and method of high speed dry gas seal face groove of bionic design, which can provide the theoretical basis for large rotating machinery with high speed project selection and design optimization of high performance of dry gas seal.

【学位授予单位】：浙江工业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TH452;TH136
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本文编号：1453056