【作者】 乐瑞文；

【导师】 陈长琦； 欧阳峥嵘；

【作者基本信息】 合肥工业大学 ， 制冷及低温工程， 2006， 硕士

【摘要】 中性束注入系统要求有洁净的动态高真空环境，大抽速液氦冷凝泵是满足此要求的理想真空获得设备。液氦冷凝泵需要定期输入大量液氦，而液氦潜热低，极易蒸发，并且价格昂贵，因此低冷损的液氦输送管道对降低实验运行成本有重要意义。同时，液氦输送管良好的绝热性能也是保证液氦冷凝泵实现高性能运行的必备条件。 本文深入分析了真空多层绝热的传热机理，建立了真空多层绝热的冷损数学模型，并对模型的非线性方程组进行数值计算；用冷损失数学模型对真空多层绝热进行了设计，设计了真空多层绝热液氦输送管；对输送管的性能进行测试，单位长度热流量为0.188W／m；经验证本冷损数学模型计算值与实验测试值之间的误差较小；设计制造的输送管用于中性束注入系统实验，满足了实际需要。 本文建立的冷损数学模型可以用于真空多层绝热的参数设计。本研究可以为将来用于EAST装置更大抽速的低温冷凝泵以及其他场合低温液体的绝热设计提供理论依据和工程实践经验。更多还原

【Abstract】 The Neutral Beam Injection (NBI) system requires a clean high vacuum environment. The liquid helium cryocondensation pump with high pumping speed is an ideal vacuum obtain device. Transferring large quantity of liquid helium to the cryocondensation pump timely is essential. Liquid helium with small latent heat is expensive and leans to evaporate. Therefore the high efficiency liquid helium transfer pipe is of important meaning in reducing operating cost. Meanwhile, the good heat insulation performance is an important factor that guarantees the good operating performance of the cryocondensation pump.In this thesis, the heat insulation type was selected and the heat transfer mechanisms of vacuum multilayer insulation (VMLI) were discussed in detail. A mathematic model of cool loss in vacuum multilayer insulation was developed. The nonlinear equations of the mathematic model were solved. The parameter of the VMLI was determined and a VMLI liquid helium transfer pipe was designed by using the mathematic model. The cool loss performance test showed that the heat transfer rate of per meter pipe is 0.188 W/m. The pipe met the requirements of the NBI system in a practical experiment.It is proved that the mathematic model of cool loss in vacuum multilayer insulation can be used in VMLI design. This research provides theoretic basics and engineering practice data for heat insulation design in a higher pumping speed cryopumps and other areas where VMLI design is needed for cryogenic liquid.更多还原