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...     

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.     

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。     

BEPCII氦制冷机冷箱故障分析和维护

BEPCII低温系统制冷机运行时间已达12年,制冷机冷箱出现了多种问题,例如:冷箱内存在压缩机油,活性炭粉末等,导致制冷机的制冷能力严重下降。为了提高制冷机的制冷能力,提高工作效率,消除隐患,针对问题开展对制冷机Plant A冷箱进行了彻底的维护。维护后制冷机运行稳定,制冷能力达到验收时的指标。     

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...     

Thermodynamic design of hydrogen liquefaction systems with helium or neon Brayton refrigerator

A thermodynamic study is carried out for the design of hydrogen liquefaction systems with helium (He) or neon (Ne) Brayton refrigerator. This effort is motivated by our immediate goal to develop a small-capacity (100 L/h) liquefier for domestic use in Korea. Eight different cycles are proposed and their thermodynamic performance is investigated in comparison with the existing liquefaction systems. The proposed cycles include the standard and modified versions of He Brayton refrigerators whose lowest temperature is below 20 K. The Brayton refrigerator is in direct thermal contact with the hydrogen flow at atmospheric pressure from ambient-temperature gas to cryogenic liquid. The Linde-Hampson system pre-cooled by a Ne Brayton refrigerator is also considered. Full cycle analysis is performed with the real properties of fluids to estimate the figure of merit (FOM) under an optimized operation condition. It is concluded that He Brayton refrigerators are feasible for this small-scale liquefaction, because a reasonably high efficiency can be achieved with simple and safe (low-pressure) operation. The complete cycles with He Brayton refrigerator are presented for the development of a prototype, including the ortho-to-para conversion.     

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.     

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。     

中国散裂中子源低温系统氦制冷系统的安装与调试

氦制冷系统是中国散裂中子源(CSNS)低温系统的重要组成部分,能够为氢循环系统提供2 200 W@20 K的冷源。介绍了CSNS氦制冷系统的组成及设备布局图及氦制冷系统的调试原理,完成了控制界面图及氦制冷系统的安装和调试准备工作,详细说明了调试的过程,获得了700 W/1 400 W/2 200 W 3种制冷功率下的状态参数。氦制冷系统调试顺利完成,结果满足了验收指标。     

氦制冷在空间制冷技术中的应用

介绍了几种用于空间制冷中的氦制冷技术，如^He减压蒸发制冷，^3He压缩相变制冷，亚临界液氦制冷，超流氦制冷等。分别介绍了它们的原理，关键技术及其应用实例，最后提出了开展这方面工作的建议。     

Design and performance of a 30 l h helium liquefier/refrigerator with plastic piston expansion engines

An all-welded, simplified expansion engine with plastic piston and plastic piston rings was designed and tested. With expansion engines of this type, a helium liquefier/refrigerator of 30 l h⁻¹ capacity was built and its design, performance and controls are described. The liquefaction cycle is a Claude cycle with the helium gas being purified by a low temperature purification circuit added inside the liquefier.This liquefier produced about 30 000 litres of liquid helium during the last twelve months.     

VM液氦温区制冷机中热压缩机性能的数值模拟与实验研究

对无负载热压缩机进行了数值模拟及实验研究,计算与实验结果表明,无负载情况下热压缩机所获得的压比主要受频率、排出器位移(即扫气量)和冷端温度的影响。排出器位移越大,压比越高;冷端温度越低,压比越高。在现有实验条件下,热压缩机工作在3 Hz时能够获得较高压比,其中排出器位移为6.0 mm时,可以获得的最高压比为1.3。计算结果与实验结果的对比表明两者能够较好吻合。     

Design and performance of a 30 l h−1 helium liquefier/refrigerator with plastic piston expansion engines

An all-welded, simplified expansion engine with plastic piston and plastic piston rings was designed and tested. With expansion engines of this type, a helium liquefier/refrigerator of 30 l h^?1 capacity was built and its design, performance and controls are described. The liquefaction cycle is a Claude cycle with the helium gas being purified by a low temperature purification circuit added inside the liquefier.This liquefier produced about 30 000 litres of liquid helium during the last twelve months.     

磁制冷器

磁制冷是一种以磁热效应为基础的制冷方法.最早是由德国物理学家于1880年发现。早期用于制取极低的温度。近年来,室温磁制冷取得了较大的突破,已经研制出适合家用的磁制冷冰箱,同时由于它的制冷系数高和对大气的全球气候变暖影响小等优点,将成为一种很有发展前途的制冷方式。本文论述磁制冷和磁制冷冰箱的基本原理。     

空气制冷机

主要叙述空气制冷机的原理及其在列车空调、冷冻冷藏、飞机空调和大型低温环境试验室中的应用。     

Mitigation of effects of pulsed heat load from fusion devices on helium refrigerator: A novel technique using vapor compression cycle

Helium refrigerators used in fusion devices are subjected to pulsed heat load. Immediate effect of such load is high fluctuation of mass flow rate at the return stream. A novel technique using vapor compression cycle at the cold end of helium refrigerators has been proposed to mitigate this flow fluctuation. The concept behind the proposed scheme is to re-liquefy excess return stream during high heat load condition and store. During low heat load condition, mitigation is obtained by increasing vapor fraction after expansion in JT valves by increasing inlet temperature of these valves. Dynamic simulation of a plant modified with vapor compression cycle has been performed and it has been found that approximately 70% and 96% mitigation of flow fluctuation during high and low heat load respectively, can be achieved. Criteria of selection and technical feasibility of critical equipment for implementation of the concept have also been discussed.