Vaghela Hitensinh, Lakhera Vikas J, Sarkar Biswanath
ITER-India, Institute for Plasma Research, Ahmedabad, 380005, India.
Institute of Technology, Nirma University, Ahmedabad, 382481, India.
Heliyon. 2021 Jan 27;7(1):e06053. doi: 10.1016/j.heliyon.2021.e06053. eCollection 2021 Jan.
The constantly increasing energy consumption along with the depleting fossil fuel resources as well as owing to the fact that the nuclear fission not being an intrinsically safe method of energy generation, it has become necessary to look for other solutions to fulfil the future energy demands. Nuclear fusion, the source of energy for billions of stars, has attracted the attention of scientists and engineers despite a lot of technical challenges in the replication of the fusion process in laboratories. For fusion to take place in a device, one of the major challenges faced is the strong magnetic confinement of the plasma using large superconducting (SC) magnets, which need efficient cryogenic cooling techniques to maintain the required low temperatures for the superconducting state. In order to maintain the compactness, the SC magnets generally employ Cable in Conduit Conductor (CICC) windings, carrying high current densities, which are cooled by the forced flow of helium at ~4 K temperature to maintain the required superconducting temperatures. The construction of CICC aims to maintain the superconductivity state by optimization of various parameters such as thermal stability, the ratio of normal conductor to SC material, mechanical strength, low hydraulic impedance, current density, magnetic field, etc. The cryogenic thermal stability of the CICC is of prime importance for safe, stable and reliable operation of SC magnets. The prediction of thermal and hydraulic behavior of the CICC in large SC magnets is difficult due to the complex geometry involved, the variation in fluid properties, various heat in-flux incidences over the long length of CICC and a complex heat transport phenomenon. Another application which utilizes a forced flow cryogenic cooling in the fusion devices is a cryo-adsorption pump for creating clean and high vacuum with large pumping speed. This paper presents an overview of the forced flow cryogenic cooling schemes in fusion devices along with a systematic review of the thermal and hydraulic studies related to CICC and cryo-adsorption pump, thereby highlighting the challenges and opportunities for further improvement in their design and performance.
随着能源消耗的不断增加，化石燃料资源日益枯竭，且由于核裂变并非本质安全的能源生产方式，因此有必要寻找其他解决方案来满足未来的能源需求。核聚变作为数十亿颗恒星的能源来源，尽管在实验室中复制核聚变过程面临诸多技术挑战，但仍吸引了科学家和工程师的关注。为了在装置中实现核聚变，面临的主要挑战之一是使用大型超导磁体对等离子体进行强磁约束，这需要高效的低温冷却技术来维持超导状态所需的低温。为了保持紧凑性，超导磁体通常采用管内电缆导体（CICC）绕组，承载高电流密度，通过在约4K温度下强制流动的氦气进行冷却，以维持所需的超导温度。CICC的构建旨在通过优化各种参数（如热稳定性、常规导体与超导材料的比例、机械强度、低水力阻抗、电流密度、磁场等）来维持超导状态。CICC的低温热稳定性对于超导磁体的安全、稳定和可靠运行至关重要。由于涉及复杂的几何形状、流体特性的变化、CICC长长度上的各种热通量入射以及复杂的热传输现象，预测大型超导磁体中CICC的热和水力行为具有挑战性。在聚变装置中利用强制流动低温冷却的另一个应用是用于产生具有大抽速的清洁高真空的低温吸附泵。本文概述了聚变装置中的强制流动低温冷却方案，并对与CICC和低温吸附泵相关的热和水力研究进行了系统综述，从而突出了它们在设计和性能方面进一步改进所面临的挑战和机遇。
