低温氦气体轴承透平膨胀机的设计

针对我国氦透平膨胀机的研制任务，设计了一台氦气体轴承透平膨胀机。从机械性能方面就该氦透平膨胀机开展了理论与试验研究，以高稳定性为主要目标进行了氦透平膨胀机的结构设计，实现了绝热及密封、快速装拆等要求。氦透平常温、低温实验证明该机具有良好的热力性能及机械性能，本文侧重于对该氦透平膨胀机结构设计的探讨。     

氦制冷系统气体轴承透平膨胀机设计

描述了氦制冷系统的流程设计,根据流程确定系统关键部件透平膨胀机的参数,设计并研制了一台氦气透平膨胀机.为达到氦透平膨胀机高速稳定性及高绝热效率的要求,采用NREC对氦透平膨胀机优化通流部分,采用FLUENT分析气体轴承性能,优化气体轴承机构,采用ANSYS分析优化转子结构参数,提高转子临界转速.现场试验结果表明优化设计后的氦透平膨胀机,在转速12万转/分钟稳定运行,绝热效率达到72％以上,达到了系统设计要求.     

径-轴流低温透平膨胀机整体性能多目标优化设计

讨论了径－轴流低温透平膨胀机整体性能多目标优化设计，对透平膨胀机，制动风机，轴向力及转子－轴承系统进行关于热力性能及机械性能的多目标优化，，开发了一套透平膨胀机设计程序。     

采用不同损失模型的低温透平膨胀机性能分析

针对氦气低温透平膨胀机变工况热力性能预测,研究了透平膨胀机各通流部分损失机理,并根据一维无量纲流动控制方程,采用基于焓降的损失系数分析了各部件内流动损失,结合各部件流动特性,确定了适合各通流部件的损失系数计算关联式,进一步开展了氦低温透平膨胀机变膨胀比和变转速的热力性能模拟研究,绘制了透平性能曲线,获得了透平膨胀机变膨...     

氦透平膨胀机的轴承 静压气体轴承在低于100K时的应用

本文介绍了日本丰田公司研制氦透平膨胀机的情况,它采用电机制动,其静压氦气轴承在液氮温度下运转。在概述了透平膨胀机的设计后,着重叙述了低温下静压气体轴承的设计和运转特性。并己应用于250升/时氦液化器和超导磁体冷却。图9,表2。     

空气轴承中压透平膨胀机试验研究

本文叙述了150 Nm~3/h制氧机空气轴承中压透平膨胀机的试验结果。对刚性装配及橡皮加稳的空气轴承进行了试验研究:研究了轴承径向间隙2 Cr、轴承供气压力 Ps、轴的材料及重量、橡胶 O 形圈的性能等参数对轴承失稳转速(自激涡动起始速度)的影响。作者还测定了轴承体的振动、轴承耗气量的变化、透平膨胀机热力性能。试验表明,该空气轴承中压透平膨胀机的性能是优良的。     

全动压气体轴承低温透平膨胀机的开发

设计了一台小型全动压气体轴承低温透平膨胀机，径向轴承采用新型弹性支承箔片径向气体轴承，止推轴承采用螺旋槽止推气体轴承。针对该透平膨胀机的机械性能做了大量试验，试验获得最大转速为220 000r/min，试验表明，该全动压气体轴承低温透平膨胀机运转稳定，对开发我国自己的全动压气体轴承低温透平膨胀机具有重要的意义。     

大功率氦气透平膨胀机的设计

介绍了大型氦气制冷机系统应用中的关键设备,大功率氦气透平膨胀机的设计。在设计中,充分考虑了大功率透平大流量,高压降的特点,对转子、气体轴承系统进行了设计、校核及优化。同时对通流部分的气动性能进行了模拟计算,得到了较高的通流效率。试验结果表明,透平膨胀机满足了10 k W@20 K制冷机系统要求,设备运行稳定。     

大功率电涡流制动氦透平膨胀机在EAST氦制冷机中的控制与调试

为保障系统的制冷量与可靠性,EAST托卡马克装置2k W氦制冷机采用了动压气体轴承电涡流制动氦透平膨胀机替代原有的油气混合轴承氦透平膨胀机。新电涡流制动氦透平膨胀机配合转子冷却回路运行,制动功率最大可达10 k W。氦透平膨胀机采用全动压径向气体轴承,而下止推轴承则引入静压气体用于增加止推轴承的承载力。目前,大功率电涡流制动氦透平膨胀机已完成在EAST氦制冷机中的安装与调试运行。介绍了电涡流制动氦透平膨胀机的测量与控制设计,在调试运行的基础上总结了氦透平膨胀机的启动与停机控制流程,并对其低温调试进行了详细分析。调试结果表明,电涡流制动的应用简化了氦透平膨胀机的启动、停机与操作流程,有助于EAST氦制冷机全自动控制的实现。     

应用于透平机械的相似模化方法评述

为解决氦透平膨胀机的相似模化试验问题，本文首先总结了以往选取透平机械相似准则的方法，进而对这些选取相似准则组织透平机械模化试验的各种方法进行了评论，其中重点评术透平机械中应用具有不同绝热指数的工质进行模化试验的多种方法，为研究以空气代替氦气进行氦透平膨胀机性能试验的问题奠定了基础。     

低温氦透平膨胀机的研究进展

对低温氦透平膨胀机的近期研究进展进行了介绍，特别指出了动压气体轴承在透平膨胀机中的应用现状与前景。     

Flow field analysis of high-speed helium turboexpander for cryogenic refrigeration and liquefaction cycles

Turboexpander constitutes one of the vital components of Claude cycle based helium refrigerators and liquefiers that are gaining increasing technological importance. These turboexpanders which are of radial inflow in configuration are generally high-speed micro turbines, due to the low molecular weight and density of helium. Any improvement in efficiency of these machines requires a detailed understanding of the flow field. Computational Fluid Dynamics analysis (CFD) has emerged as a necessary tool for the determination of the flow fields in cryogenic turboexpanders, which is often not possible through experiments.In the present work three-dimensional transient flow analysis of a cryogenic turboexpander for helium refrigeration and liquefaction cycles were performed using Ansys CFX®, to understand the flow field of a high-speed helium turboexpander, which in turn will help in taking appropriate decisions regarding modifications of established design methodology for improved efficiency of these machines. The turboexpander is designed based on Balje's n_sd_s diagram and the inverse design blade profile generation formalism prescribed by Hasselgruber and Balje. The analyses include the study of several losses, their origins, the increase in entropy due to these losses, quantification of losses and the effects of various geometrical parameters on these losses. Through the flow field analysis it was observed that in the nozzle, flow separation at the nozzle blade suction side and trailing edge vortices resulted in loss generation, which calls for better nozzle blade profile. The turbine wheel flow field analysis revealed that the significant geometrical parameters of the turbine wheel blade like blade inlet angle, blade profile, tip clearance height and trailing edge thickness need to be optimised for improved performance of the turboexpander. The detailed flow field analysis in this paper can be used to improve the mean line design methodology for turboexpanders used in helium refrigeration and liquefaction cycles.     

空气制冷机微机动态测试系统及分析软件的开发

针对空气制冷机系统实验台的特点 ,设计了一套微机动态测试系统及数据分析、处理软件 ,可方便快捷地对空气制冷机系统的机械性能、热力性能进行测量及在线分析     

EAST装置2 kW/4.5 K氦制冷机透平膨胀机的测试

EAST装置于2006年成功进行工程调试和物理实验,全部超导磁体均已冷却到液氦温度,并获得了第一次等离子体.低温系统共有4台俄制氦透平膨胀机,通过气体绝热膨胀来获得低温.实验表明4台透平的设计满足EAST装置对冷量的需求,透平效率略低于设计值,流量比设计值大.介绍了EAST低温系统中4台透平膨胀机的设计参数、启动过程和运行,并对透平膨胀机在运行过程中的性能参数进行测试和分析.     

氢氦混合工质脉管制冷性能研究

由于氢气具有优越的传热和流动特性,有望减少脉管制冷机回热器的流动和传热损失,从而可获得高于纯氦工质的制冷性能.从氢组分对循环热力学性能、流体流动与传热性能等因素的影响角度出发,开展了氢-氦混合工质脉管制冷性能研究,并在30 K温区进行了实验验证,获得了比纯氦更好的制冷性能.     

Applicability of equations of state for modeling helium systems

Proper design of helium systems with large number of components and involved configurations such as helium liquefiers/refrigerators requires the use of tools like process simulators. The accuracy of the simulation results, to a great extent, depends on the accuracy of property data. For computation of thermodynamic properties of helium, the 32-parameter MBWR equation of state proposed by McCarty and Arp [1] is widely used. However, it is computationally involved, makes the simulation process more time-consuming and sometimes leads to computational difficulties such as numerical oscillations, divergence in solution especially, when the process operates over a wide thermodynamic region and is constituted of many components. Substituting MBWR EOS by simpler equations of state (EOS(s)) at selected thermodynamic planes, where the simpler EOS(s) have the similar accuracy as that of MBWR EOS may enhance ease of computation. In the present paper, the methodology to implement this concept has been elucidated with examples of steady state and dynamic simulation of helium liquefier/refrigerator based on Collins cycle. The above concept can be applied to thermodynamic analysis of other process cycles where computation of fluid property is involved.     

实用氦气声学温度计初步研究

对高温气冷堆堆芯温度的可靠测量是目前的技术难题之一。传统温度计依靠实验室标定的材料特性与温度的关系进行测温,然而,长期暴露在高温、高辐照环境中,其测温材料的性质会发生改变且得不到及时校准,温度传感器易发生漂移甚至失效。气体声学温度计通过测量单原子气体的声速可以直接获得热力学温度;由于气冷堆内氦气介质相对稳定,利用氦气声速获得温度具有较高的可靠性。针对实用氦气声学温度计开展了初步研究,基于圆柱声学共鸣法设计了实用声学温度计测试系统,采用声波导管声学传感器测量了488K至806K圆柱共鸣腔内氦气的声学共振频率,修正了热边界层和粘性边界层的影响;基于量子力学从头算得到的氦气声学维里状态方程,获得了热力学温度。对氦气共振频率的测量相对标准偏差小于0.07%,温度测量的信噪比可满足需求,声学温度计与热电偶测温结果差异小于1%。研究结果为未来持续开展极端环境下气体声学温度计的应用研究提供了支持。     

透平膨胀机新型动压径向气体轴承的试验研究

对一种用于高速低温透平膨胀机的新型平箔式箔片径向动压气体轴承进行了试验研究，试验箔片径向轴承的直径为φ２５．０ｍｍ，在１５０Ｎｍ＾３Ｏ２／ｈ制氧机用透平膨胀机上达到了１２．１６万ｒ／ｍｉｎ，超速４％的良好试验效果，通过对多种组合结构参数的轴承－转子系统稳定性能的分析，得出了最佳实验结构参数的范围，为今后在透平膨胀机上开发及应用新型平箔径向动态气体轴承提供了设计依据。试验结果表明，此种结构的箔片轴承     

Tests on large diameter superconducting solenoids designed for colliding beam accelerators

Two prototype large diameter thin coil solenoids which use the mechanical structure to moderate quenches, have been built and systematically tested. The solenoids are cooled by two phase helium flowing in tubes which form a part of the coil structure. The coils have been tested by inducing a series of quenches at various currents. The results of these tests are given in this paper.