低温永磁波荡器过冷液氮冷却系统及其关键设备的计算分析和控压关键技术的实验研究

发布时间：2018-02-22 03:27

本文关键词： 低温波荡器过冷氮冷却系统过冷换热器液氮泵控压技术　出处：《中国科学院研究生院(上海应用物理研究所)》2017年硕士论文　论文类型：学位论文

【摘要】：低温永磁波荡器(Cryogenic Permanent Magnet Undulator,CPMU)是目前插入件技术发展的主要方向之一,其利用某些永磁材料如钕铁硼(NdFeB)或镨铁棚(PrFeB)的磁场性能在低温下明显高于室温的特性,达到提高波荡器性能和光源束流品质的目的,CPMU工作温区在50K?150K之间。低温冷却技术是实现CPMU运行的必要条件和关键技术之一。CPMU冷却主要包括过冷液氮冷却系统和CPMU磁体阵列冷却回路,过冷液氮冷却系统为CPMU磁体的冷却提供冷量和冷却工质。中科院上海应用物理研究所从2013年开始低温波荡器的研制工作并开展了CPMU相关关键技术的研究,2014年和2016年分别研制出国内首台钕铁硼CPMU样机及其过冷液氮冷却装置。该样机及其冷却系统2016年整体安装于上海光源进行在线测试,其相位误差在室温与低温下均小于3度,达到国际水平;其过冷液氮冷却系统的性能优于设计指标且运行稳定。过冷液氮冷却系统是CPMU离线测试及在线运行的必要条件之一。本论文以上海光源自主研发的CPMU过冷液氮冷却系统为对象,采用理论分析和实验测试的方法,开展了过冷液氮冷却系统及其关键设备的计算分析和控压关键技术的实验研究,研究结果为SINAP研发具有自主知识产权的过冷液氮冷却系统提供了一定的理论依据。本文首先在CPMU过冷液氮冷却系统的流程设计方案和设计参数基础上,进行了系统主要热负载的计算和分析,根据热负载分析结果对系统的流程热力参数进行了计算分析,得到CPMU过冷液氮冷却系统的制冷能力与流量、温度的关系,为CPMU过冷液氮冷却系统的调试提供了理论依据,并对其关键设备过冷换热器提供了设计参数。过冷换热器是CPMU过冷液氮冷却系统的关键设备之一,过冷液氮和冷源常压饱和液氮通过过冷换热器交换热量,过冷换热器选用盘管式换热器,本文对盘管换热器的换热面积进行了理论计算,得出了过冷换热器的结构参数。液氮泵是CPMU过冷液氮冷却系统的另一关键设备,为过冷液氮补充冷却循环过程中的压降损失,提供循环动力。CPMU磁体冷却管路与过冷液氮冷却系统之间通过液氮传输管线连接,CPMU样机与过冷液氮冷却系统之间管路较复杂,本文计算分析了过冷氮流经CPMU冷却系统的全程阻力损失,得到了循环系统的管路特性曲线,为液氮泵的选型和液氮泵的运行调试提供了依据。最后,本文对CPMU过冷液氮冷却系统进行了在线测试,得到了CPMU过冷液氮冷却系统的运行参数。实验测试结果表明,系统的低温性能达到并优于了设计要求。同时,对系统进行了控压技术的实验测试研究,得到了控压容器内压力稳定所需的运行条件,即控压容器内液氮所占容积比率低于40%,使控压容器内压力稳定性2kPa,达到了系统压力控制设计要求7kPa。该冷却系统不仅可用于CPMU的冷却运行,也满足光束线单色器的冷却要求。
[Abstract]:Cryogenic Permanent Magnet impeller is one of the main directions in the development of insert technology. The magnetic field properties of some permanent magnetic materials, such as NdFeB or PrFeB, are obviously higher than those at room temperature at low temperature. In order to improve the performance of the waver and the beam quality of the light source, CPMU operating temperature range is 50 K? Between 150K and 150K. Low temperature cooling technology is one of the necessary conditions and key technologies to realize CPMU operation. CPMU cooling mainly includes undercooled liquid nitrogen cooling system and CPMU magnet array cooling loop. The supercooled liquid nitrogen cooling system provides cooling quantity and refrigerant for the cooling of CPMU magnets. Since 2013, the Shanghai Institute of Applied Physics of the Chinese Academy of Sciences has started the development of the low temperature waver and has carried out the research on the key technologies related to CPMU, 2014 and 2016. The first NdFeB CPMU prototype and its supercooled liquid nitrogen cooling device were developed in China in 2003. The prototype and its cooling system were installed in Shanghai Light Source for on-line testing in 2016. The phase error is less than 3 degrees at room temperature and low temperature, reaching the international level. The performance of the supercooled liquid nitrogen cooling system is superior to the design index and the operation is stable. The supercooled liquid nitrogen cooling system is one of the necessary conditions for the offline test and on-line operation of CPMU. This paper takes the CPMU supercooled liquid nitrogen cooling system developed by Shanghai Light Source as the object. By means of theoretical analysis and experimental test, the calculation and analysis of the supercooled liquid nitrogen cooling system and its key equipment and the experimental research on the key technology of pressure control are carried out. The results provide a theoretical basis for SINAP to develop an undercooled liquid nitrogen cooling system with independent intellectual property rights. Firstly, based on the process design scheme and design parameters of CPMU supercooled liquid nitrogen cooling system, The calculation and analysis of the main heat load of the system are carried out, and the thermodynamic parameters of the system are calculated and analyzed according to the results of the thermal load analysis. The relationship between the cooling capacity of the CPMU subcooled liquid nitrogen cooling system and the flow rate and temperature is obtained. It provides a theoretical basis for the commissioning of the CPMU supercooled liquid nitrogen cooling system, and provides the design parameters for the supercooled heat exchanger, which is one of the key equipments of the CPMU supercooled liquid nitrogen cooling system. The supercooled liquid nitrogen and saturated liquid nitrogen exchange heat through the supercooled heat exchanger. The coiled tube heat exchanger is used in the supercooled heat exchanger. The heat transfer area of the disc tube heat exchanger is calculated theoretically in this paper. The structural parameters of the supercooled heat exchanger are obtained. The liquid nitrogen pump is another key equipment of the CPMU supercooled liquid nitrogen cooling system, which replenishes the pressure drop loss during the cooling cycle for the supercooled liquid nitrogen. Providing circulating power. CPMU magnet cooling line and supercooled liquid nitrogen cooling system. The connection between CPMU prototype and undercooled liquid nitrogen cooling system through liquid nitrogen transmission pipeline is more complicated. In this paper, the total resistance loss of undercooled nitrogen flowing through CPMU cooling system is calculated and analyzed, and the characteristic curve of the circulating system is obtained, which provides the basis for the selection of liquid nitrogen pump and the operation and adjustment of liquid nitrogen pump. In this paper, the on-line test of the CPMU supercooled liquid nitrogen cooling system is carried out, and the operating parameters of the CPMU supercooled liquid nitrogen cooling system are obtained. The experimental results show that the low temperature performance of the system is up to and superior to the design requirements. The pressure control technology of the system is experimentally tested and studied, and the operating conditions for the pressure stability in the controlled pressure vessel are obtained. The ratio of liquid nitrogen in the controlled pressure vessel is less than 40, which makes the pressure stability of the controlled pressure vessel 2kPa, which meets the design requirement of system pressure control. The cooling system can be used not only for the cooling operation of CPMU, but also for the beam line Monochromator.
【学位授予单位】：中国科学院研究生院(上海应用物理研究所)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM273;TB65

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