随着我国近年来工业化与现代化进程的不断推进，各类能源的开采量与消耗量不断增加；同时，我国的能源生产集中于西北部，消费则集中于东南沿海，地理分布并不均衡。针对这一现状，我国需要发展能源的远距离、高效率、大容量输送技术。在此背景下，超导能源管道作为一种新型能源传输技术被提出，其将超导输电与液态化学燃料输送相结合，液态化学燃料同时可作为能源管道的制冷剂，故可以在降低制冷系统成本的同时，实现电能与化学能的大容量一体化输送。目前，超导能源管道距离走向工程实用仍有一段路程。由于其同时包含了超导电缆输电、流体管道输送、低温制冷等系统，电场、热场、流体场等各种物理场的相互影响为研究超导能源管道的运行状态带来了一定的复杂性。为推进其尽快走向实用，有必要对超导能源管道中的多物理场问题进行分析。本文首先介绍了超导能源管道电-热-流多物理场耦合的理论模型，分析了能源管道正常运行状态和短路故障状态中的电-热-流多物理场之间的耦合关系。在此基础上本文针对30 m、100 kV/1 kA超导直流能源管道样机建立了电-热-流多物理场耦合的数值模型，并介绍了基本仿真设置等。通过建立的数值模型，本文对超导能源管道样机在正常运行工况、过流失超故障和LNG停滞故障下的运行特点分别进行了分析。通过对长距离超导能源管道的正常工况进行仿真分析，本文推导出了能源管道在实际工程建设时所需的加压制冷站的间距限制。通过对超导能源管道样机在过流失超下的故障工况进行仿真分析，研究了不同铜支撑厚度对故障暂态温升的影响，得到了给定管道参数下超导能源管道铜支撑厚度的最小值。通过对超导能源管道样机在LNG停滞的故障工况进行仿真分析，得到了在该故障下超导能源管道的最长故障修复时间。最后，本文考虑超导能源管道系统在运行过程中可能面临的压力和温度扰动，设计了一种抗扰动协同控制策略，该协同控制策略包括压力反馈控制和温度反馈控制两部分，并分别在30 m样机模型和5 km长距离模型中进行了抗扰动仿真测试。根据仿真结果进行分析显示，该控制策略在末端瞬时压力扰动、外界环境漏热扰动和末端瞬时热突变的小扰动情况下，可以有效维持管道末端温度和压力位于设计的运行区间内，保证管道系统的稳定性和安全性。
With the development of industrialization process in China, the energy exploitation and consumption increase contiously. The energy production is concentrated in the northwest part of China, while the energy consumption is concentrated in the southeast coast. In view of this situation, the long-distance, large-capacity and high-efficiency energy transmission technology need to be developed in China. Superconducting energy pipeline is proposed as a new energy transmission technology, which combines superconducting power transmission with liquefied fuel transportation. The liquefied fuel can also be used as refrigerant for the energy pipeline, which can reduce the cost of refrigeration system and realize the integrated transmission of electric energy and chemical energy. At present, there is still a long way for superconducting energy pipelines to be used in practical engineering. As the superconducting energy pipeline combines superconducting power transmission system, pipeline transmission system and cryogenic refrigeration system at the same time, the operation state of superconducting energy pipeline is complex with the interaction of electric field, thermal field and fluid field. So it is necessary to analyze the problem of multi-physical field in superconducting energy pipeline.In this paper, the coupling theoretical model of electric-thermal-flow field in superconducting energy pipeline is introduced firstly, and the relationships among the multiple physical fields of superconducting energy pipeline in normal operation state and short-circuit fault state are analyzed. On this basis, a electric-thermal-flow multi-physical field coupling numerical model is established for the prototype of 30 m, 100 kV/1 kA superconducting DC energy pipeline, and the basic simulation Settings are introduced.Based on the established numerical model, this paper analyzes the operation characteristics of the superconducting energy pipeline prototype under normal operation conditions, superconducting cable quench fault and LNG stagnation fault respectively. Based on the simulation results of superconducting energy pipeline prototype under normal working conditions, and extending to a long distance superconducting energy pipeline, the distance limit of the pressurized-refrigeration stations is given, which is required by the energy pipeline in actual engineering construction. Based on the simulation results of superconducting energy pipeline prototype under superconducting cable quench fault condition, the influence of thickness of copper skeleton on transient temperature rise is analyzed, and the minimum copper skeleton thickness of superconducting energy pipeline is derived. Based on the simulation results of results of superconducting energy pipeline prototype under LNG stagnation fault condition, the longest repair time of superconducting energy pipeline under this fault is derived.Finally, considering the pressure and temperature disturbances that the superconducting energy pipeline system may occur during operation, a cooperative control strategy is designed, and the simulation tests are carried out in the 30 m prototype model and a 5 km long distance model respectively. According to the simulation results, this cooperative control strategy can effectively maintain the temperature and pressure at the end of the pipeline within the designed operating range under the terminal pressure disturbance, the external environment heat leakage disturbance and the small terminal thermal disturbance. This shows that the control strategy can ensure the security of the superconducting energy pipeline system.
