油气混合氦透平膨胀机在EAST低温系统中应用现状研究

介绍用于EAST(Experimental Advanced SuperconductingTokamak)低温系统中特殊结构的氦透平膨胀机,并且指出在当前降温过程中氦透平膨胀机不稳定性问题。分析2种降温模式(使用透平D和不使用透平D)对制冷机性能的影响,结果表明不使用透平D将会大大降低制冷机的性能。在现有条件下提出对静压气体轴承的改进设计,试验结果表明此方法能有效改善氦透平膨胀机的稳定性。     

透平膨胀机气体静压轴承的修复

介绍了PLN－6／4－0．25型透平膨胀机气体静压轴承在生产运行中常见的故障，在作业现场采取了合理的修复措施和切实可行的修复方法，消除了故障的根源，大大减少了停机次数，保证了生产正常运行。     

大型透平膨胀机气体轴承设计

空分装置中的透平膨胀机,是一种高速机械,目前这种机器上的轴承均采用油润滑。为避免润骨油对工质的污染,提高膨胀效率,更新传统的油轴承是有意义的。为此,我们研究了国产6000m~3/h制氧装置中透平膨胀机的轴承系统,肯定了在这种机械上应用气体轴承的可行性。     

气体轴承透平膨胀机安装与应用

<正> 1.气体轴承透平膨胀机的工作原理气体轴承用气体作润滑剂,在轴与轴承之间构成气膜,使活动面与静止面避免直接地接触,这就是气体轴承的原理。用压缩空气在膨胀机内绝热膨胀直接产生冷量获得低温,并使空气在空分塔中节流液化,同时补偿空分设备中的各种冷量损失,透平膨胀机     

透平膨胀机气体静压轴承的修复

介绍了PLN-6/4-0.25型透平膨胀机气体静压轴承在生产运行中常见的故障,在作业现场采取了合理的修复措施和切实可行的修复方法,消除了故障的根源,大大减少了停机次数,保证了生产正常运行。     

透平膨胀机新型切向小孔气体轴承静特性的实验研究

为减小普通切向小孔供气轴承的耗气量,本文提出了一种新型切向小孔供气轴承。静态性能的测试表明,这种新型轴承具有耗气量小、刚度大等优点。     

气体轴承透平膨胀机故障分析与处理

气体轴承透平膨胀机的故障诊断和处理,对保证整个制冷系统安全运行有重要影响。分析气体轴承透平膨胀机的结构组成对故障诊断意义重大。通过静平衡和动平衡试验消除由于转子不平衡引起的卡机故障。对转子超载引起的卡机故障应规范操作,保证启动和运转时不超速。分析了轴承所受的径向载荷和频繁启停及闪停电引起的影响气体轴承稳定性的问题,指出了供气压力、径向半径间隙及转子的平衡性间的关系。通过调整机壳与工作轮叶片的间隙避免内泄漏的增大。采取调整工作轮后部的密封间隙和充足的密封气量等措施减少外泄漏的发生。分析了液击故障产生的原因,提出处理方法。对管路堵塞、轴承气不洁净引起的运行故障作了分析处理。提出通过严格动静平衡试验、正确组装、规范操作以及经常维护等方法来保证气体轴承透平膨胀机的安全稳定运行。     

向心透平发电膨胀机静压气体轴承设计与承载特性分析

为提升有机朗肯循环（organic Rankine cycle,ORC）系统向心透平发电膨胀机静压气体轴承的承载力与刚度,采用表压比法设计了以R245fa为润滑工质的静压气体轴承,分析转子偏心率、供气孔尺寸、进气压力对静压气体轴承承载力与刚度的影响。实验结果表明：在相同供气压力下,轴承承载力与刚度随着转速的增大而增大;在相同转速下,0.7 MPa供气压力相对于其他气体供气压力轴承的承载力与刚度略高;静压气体轴承的偏心率越大承载力越大;相同供气孔直径下,静压气体轴承的承载力与刚度随着转速的升高而升高;随供气孔直径增大,静压气体轴承的承载力和刚度也随之增大。     

透平膨胀机气体轴承的数值模拟

应用ANSYS有限元软件对透平膨胀机的核心部件——气体轴承进行模态分析和谐响应分析,求解转子的振型、应力分布、固有频率和失稳转速。并对不同轴承半径间隙时的转子动力学分析,根据失稳转速的变化规律,得出所设计的双排径向静压气体轴承的最佳轴承半径间隙:Cr=0.02 mm。     

氦气体轴承透平膨胀机研制

根据氦制冷系统的要求设计氦透平膨胀机,按透平膨胀机的整体热力性能及机械性能进行多目标优化方法设计,对氦透平膨胀机的结构形式、热力性能进行优化设计。对传统的 Riccati 传递矩阵法改进推导进行临界转速求解,提出一种切向进气的静压气体轴承结构形式,通过设置回气孔和轴向排气孔,提高主轴的失稳转速。通过现场氦气试车,氦透平膨胀机运转平稳,热力性能优异,表现出良好的整机性能,完全达到了氦制冷系统的设计要求。     

一种球面气体静压轴承的建模与仿真

介绍了一种小孔节流式球面气体静压轴承,该轴承的加工工艺性较好,而且在各个方向上都有较大的支承力;针对该轴承支承力的计算提出了一种有限划分计算方法,在建模中考虑到气膜压力分布的不对称性,将轴承根据节流孔的数目划分为数个等分,对每个等分再进行有限划分,若划分数足够多,可以认为在每个小等分中的气膜压力沿划分方向无变化,以小等分中心的压力代替,从而简化了轴承的气膜压力分布的求解;借助MATLAB软件队轴承的支承性能进行了仿真计算,并通过实验进行比较验证,实验结果与仿真结果基本一致。     

Externally Pressurized Journal Gas Bearings

Externally pressurized gas-lubricated bearings with multiple orifice feed are investigated. An analytical treatment is developed for a semicylindrical bearing with 9 orifices and for a cylindrical journal bearing with 192 radial and 24 axial orifices.

Experiments are described on models of the two bearing configurations with specially designed fixtures which incorporate pneumatic loading and means for determining pressure profiles, gas flow, and gap height. The correlation between theory and experiment is satisfactory.     

基于VB程序的气体静压轴承设计

气体静压轴承的结构参数对其工作特性有很大的影响,传统的设计方法过程复杂烦琐.本文以VB编程语言为开发工具,对气体静压轴承进行工程计算及参数的优化设计,以获得合理的结构参数.用VB编写的设计软件使用方便,提高了气体静压轴承设计精度和效率,实现了设计快速、简捷、自动化.     

静压气体轴承设计支持系统的研究

本文介绍了静压气体轴承设计支持系统的总体方案。在分析了静压气体轴承设计特点的基础上,提出了一种用事件并借鉴面向对象的技术来表达的基于知识推理的方法来实现本系统的设计。     

Tri-Conical Gap-Shaped Externally Pressurized Gas Bearing Pads

Externally pressurized gas (EPC) bearing pads with convergent conical shapes can provide high load capacity and high stiffness. Research has revealed that if the suitable combination of gap difference and working gap height is chosen, the optimized diameter ratios for stiffness and load capacity are close to the same value, about 0.8 to 0.9, or the ratio of the diameter of the conical gap-shaped part over the pad diameter. The optimized diameter ratio is independent of the supply pressure, the pad diameter and the number of conical parts. Conversely, the stability of the bearings is controlled by the combination of the diameter ratio and the gap difference. From the analysis of the stability criteria and the optimized diameter ratio, the concept of the tri-conical gap-shaped EPG bearing pads was proposed. Numerical and experimental investigation shows that under the same stable conditions, tri-conical gap-shaped pads provide higher stiffness and higher load capacity than simple conical or parallel gap-shaped pads.     

小孔节流静压气体轴颈轴承的静态特性研究

通过对小孔节流静压气体轴颈轴承润滑方程的分析,利用泛函求极值法将二阶偏微分方程降为一阶,采用有限元方法,利用三角单元线性插值函数,简化压力分布方程式的计算,对轴承的参数进行了优化,得到了轴承上各点的压力分布和轴承的承载能力和支承刚度,并分析了轴承间隙和偏心率等因素对承载能力和刚度的影响。     

Performance Research on the Externally Pressurized Gas Journal Bearing under Different Working Gas Based on Finite Difference Method

利用有限差分方法编写一套可以用于分析动静压气体轴承性能的计算程序,并通过已有算例和试验验证本程序计算结果的可靠性.对不同润滑介质下静压轴颈轴承气体消耗量进行研究发现,不同分子量润滑介质下气体消耗量随偏心率变化表现出不同的变化规律,小分子润滑介质下气体消耗量与偏心率成正比,而大分子润滑介质下气体消耗量与偏心率成反比,并且此规律与节流小孔类型无关,小孔节流轴颈轴承气体消耗量大于环面节流类型轴颈轴承.相同供气压力和偏心率情况下,小分子润滑介质小孔节流轴颈轴承承载能力比环面节流类型轴承承载能力小,大分子润滑介质下正好相反.本程序方法为后来对俄罗斯油—气混合低温氦透平膨胀机气体轴承端改造奠定了理论基础.     

The Design of Externally Pressurized Gas Lubricated Bearings by the Method of Bearing Equivalence

This paper presents the theoretical development and experimental verification of a simplified technique for the design of externally pressurized gas lubricated bearings. The general procedure is to establish an equivalent rectangular bearing which is the performance replica of an arbitrary gas bearing configuration. The resulting equivalent bearing has the same load support, clearance, area, source pressure, entrance losses, and mass flow as the arbitrary bearing which is analyzed. In accomplishing this end, the general rectangular bearing is analyzed, a consistent criterion of equivalence is defined, and theoretical analyses are compared to experimental data.     

The Externally Pressurized,Porous Wall,Gas-Lubricated Journal Bearing.

The externally pressurized, gas-lubricated journal bearing consisting of a porous bushing, through which gas enters the clearance space, is analyzed. The classical Reynolds' equation for laminar, isothermal, compressible flow in a finite journal bearing is modified to allow for the local mass flow through the porous bushing into the clearance space due to the difference between the constant supply pressure and the pressure within the bearing. At low mass flow rates, it is assumed that the flow in the porous bushing obeys the Darcy equation for isothermal, compressible “creeping flow.” The analysis is extended to include bearings with higher flow rates by a simple modification of the Darcy equation.

The modified Reynolds' equation is solved for the case where the shaft does not rotate by perturbing the mass flow rate through the bearing using the eccentricity ratio as a small parameter. An asymptotic solution for the “short bearing” and the “maximum load-carrying capacity” is determined independent of the perturbation technique. The results of the perturbation technique are compared numerically with the results of the asymptotic solution, and they are found to be in agreement.