BEPCⅡ氦制冷机一级换热器故障分析及处理

BEPCⅡ氦制冷机的一级换热器在前两轮运行中出现故障,换热效率降低,导致氦制冷机制冷量下降,影响了BEPCⅡ的正常运行。一级换热器的结构较为复杂,故障分析难度较大。介绍了一级换热器的结构和流程,再根据一次温度突变,通过分析找到发生故障的位置。制定并完成了相关的处理方案,使得一级换热器和氦制冷机恢复正常。     

氦制冷机的效率

随着超导技术发展和广泛应用,它对低温系统的容量要求也越来越庞大。对于大型超导磁体系统的氦制冷系统,其效率直接影响大型超导装置的运行费用。论述了影响氦制冷机效率的各种因素,并指出了提高制冷机效率的各种基本途径。     

氦制冷机和液化器中的纯化系统

主要介绍了氦制冷机和氦液化器中应用的几种典型的氦纯化器的工作原理，主要工作程序和优缺点，并介绍了讨论了几种氦纯化器的设计方案，吸附量和计算以及可用于氦纯化器的工程设计。     

超小型透平式氦制冷机

日立制作所于1986年11月6日报道了一种超小型透平式MET-50氦制冷机。该制冷机的心脏部分是超小型透平膨胀机。该制冷机采用的具有特殊形状叶片的超小型透平膨胀机，每分钟有82万转的超高转速。透平转子采用了气体轴承，因此，无磨损，比往复式的振动轻、噪音小，且可靠性高。     

EAST氦制冷机静态模拟分析

采用机理建模的方法建立了EAST制冷机单元部件和流程的静态数学模型,用C++语言开发出对应静态模型的模拟计算软件,应用该软件分别对4.5 K液化/制冷和4.5 K液化/制冷+3.5 K制冷流程进行静态模拟计算,并分析了4.5 K液化/制冷+3.5 K制冷模式下制冷机各单元部件的有效能损失以及制冷量与各项热力学参数之间的...     

BEPCII SSM磁体控制阀箱内氦冷却管线热应力分析

北京正负电子对撞机重大改造工程(BEPCII)超导螺线管磁体(SSM)的控制阀箱是该磁体低温冷却系统的主要设备之一,用来分配、调节和控制超导磁体及其电流引线的冷却介质流量。低温下磁体超导导线及其冷却管会产生冷缩变形,变形量要在控制阀箱内给与补偿。同时阀箱内来流和回流氦冷却管线布置紧凑,需要判断是否要采取措施来补偿冷缩变形。本文运用有限元分析软件ANSYS对BEPCII SSM控制阀箱内冷却管线的热应力进行模拟及分析,从而为该阀箱内冷却管线的设计及布局提供理论依据。     

溴化锂制冷机溶液的维护和再生

溴化锂制冷机组要使制冷效果始终处于最佳状态，机组使用寿命延长，除保证机组处于良好的气密性外，对机用溴化锂溶液进行日常维护、定期检测和调整是必不可少的。     

氦制冷机节流级的最佳工作点

在氦制冷机/液化器中,最末级的冷却一般采用节流方式.节流级的各参数的选择必然会影响氦制冷机的制冷量或氦液化率.讨论了节流级节流前压力、末级换热器的热端温度及其效率对制冷量或液化率的影响,得出了不同模式下的节流级的最佳工作点.     

TCF-20氦液化器-制冷机简介

简介苏尔寿TCF-20氦液化器的性能参数、流程和总体布置。并介绍压缩机参数和标准设备配套选择方案(可作液化器用,也可作制冷机用)。用液氮预冷,可提高产量。加纯化器,使原料氦含有杂质时也能正常工作。图2表4。     

氦制冷机油气分离器设计及除油效果测试

对高压氦气的除油过程进行理论分析,将过程分为捕集-聚结-排液3个部分,并对捕集过程进行理论计算,在不考虑二次夹带的情况下,一级、二级油气分离器对油滴的理论捕集效率应大于97%和99.6%。对油气分离器进行结构设计,并通过实验检验设计的油气分离器的除油效果。测试结果显示一级油气分离器除油效率达到97.625%,与理论捕集效率较为一致;二级油气分离器除油效率67.37%,对二级除油效率与理论捕集效率存在偏差进行了分析。综合除油效率达到99.25%,满足工程设计要求。     

Failure analysis and redesign of the evaporator tubing in a Kimchi refrigerator

A failure analysis was conducted on a pitted aluminum tubes in the evaporator used to cool, a Kimchi refrigerator. The root cause of the failure was a pitting corrosion which was traced to chlorine in a cotton adhesive tape used on the tubes. To reproduce the failure modes and mechanisms causing the tube pitting corrosions, a tailored set of accelerated life tests was applied to the evaporator tubing. Using chemical loads, the key noise parameters in the assembly, including a variety of chemical reaction formula, were analyzed. The failure modes and mechanisms found experimentally were identical to those of the failed sample. To correct the problem, the cotton tape in the cooling evaporator was replaced by a generic transparent tape. The B₁ life of the new design is now guaranteed to be over 10 years with a yearly failure rate of 0.1%.     

基于遗传算法的20 K氦制冷机的优化设计及其热力学分析

通过计算机程序实现10 k W@20 K的大型氦制冷机的热力学过程,在此基础上分析了流程中压缩机和透平膨胀机入口压力对系统制冷系数和效率的影响。同时与Matlab编写的遗传算法接口相连交互数据,从而实现针对该制冷机热力学参数的优化。选取制冷量和系统效率的加权值为优化目标,压缩机和透平膨胀机入口压力为待优化参数,通过遗传算法(GA)的优化计算得到了稳定的最优解,表明遗传算法在优化大型制冷系统过程中可以快速高效搜索到满足目标要求的全局最优解。     

Failure analysis of coal pulveriser gear box

The premature failure of coal pulveriser gear box has been studied in this investigation. Complete breakage as well as cracking in a number of gear teeth were noticed in which the cracking initiated from the middle of the root-fillet of the teeth and propagated beneath the root region. Studies were conducted using microstructural studies, hardness measurements, fracture surface studies, etc. The failure was found to be initiated by bending fatigue from the root fillet region of teeth which mainly constituted coarse ferrite–carbide aggregate resulting in a relatively low hardness level. The life of gear box could be improved by local hardening of the fillet root to provide a fine martensitic structure with hardness in the range of 55RC.     

螺杆制冷机的清洗及保养修理

螺杆制冷机稳定运行8年后,制冷能力下降,随时可能影响空分设备的稳定运行。用离子静电处理器清洗制冷机的换热器,拆检制冷机并对存在的缺陷进行合理处理,提高了制冷机的制冷效率。     

太阳能光伏直流蓄冷冰箱系统的可行性分析

太阳能光伏利用技术能够有效解决环境污染和能源紧张的问题。本文介绍太阳能光伏直流蓄冷冰箱系统的组成及原理,该系统综合太阳能光伏制冷技术、直流变频技术以及相变蓄冷技术的优点,阐述太阳能光伏直流蓄冷冰箱系统的技术经济可行性及应用前景。     

液氦温区小型节流制冷机发展现状及趋势

随着国际空间与地面制冷技术的不断发展,对液氦温区甚至超流氦温区的冷环境需求场合越来越广.针对目前国外在深低温超小型节流制冷器方面的研究已经开展并取得可观成果,介绍了有关J-T节流的原理、J-T节流制冷机的结构等有关知识,概述了当前国外10 K以下温区J-T节流制冷机的应用情况,对液氦温区J-T节流制冷机的发展前景进行了...     

Thermal design and tests of a subcooled superfluid helium refrigerator

Design methods for a subcooled superfluid helium refrigerator with high efficiency are studied. The design details are presented for a He I heat exchanger (perforated disk stack type), a He II heat exchanger (low fin tube type), an expansion valve, a safety valve, an initial filling valve and a pumping system. Heat loss, cooling capacity and cooldown time are also calculated. The test results for the trial-manufactured refrigeration system are presented in comparison with the designed values.     

Dynamic simulation of the helium refrigerator/liquefier for LHD

A real-time dynamic simulation has been carried out for the 10 kW class helium refrigerator/liquefier of Large Helical Device (LHD) at National Institute for Fusion Science (NIFS). The refrigerator consists of eight screw compressors, seven expansion turbines, fourteen heat exchangers and a 20 m³ liquid helium reservoir. A simulation model was implemented to Cryogenic Process REal-time SimulaTor (C-PREST), developed as a platform for the plant process study and optimization. Validity of the simulation model has been confirmed based on the design values as well as the results of commissioning tests. This paper describes the cooldown process and expansion turbine trips during the operation. Difficulties of dynamic simulation for the large cryoplant are also discussed.