Development And Performance Research Of A CICC Test Facility

In order to satisfy the test requirements of the CICC(cable-in-conduit-conductors)which are applied to the CFETR(Chinese Fusion Engineering Test Reactor),a large CICC test facility has been developed at the High Magnetic Field Laboratory of the Chinese Academy of Sciences.The facility is supported by the Ministry of Science and Technology for the ITER special fund,depending on the 1 IT superconducting magnet of a 40T hybrid magnet.The CICC test facility not only can meet the test requirements of the conductors which are applied the CFETR and other high superconducting magnets,but also can improve the CICC experimental research.According to the research of the test facility and the experiment of the CICC,the cryogenic and applied superconducting technology,superconducting magnet technology and its structure design,performance evaluation and so on the related technology can be developed very much.This dissertation focus on the design and performance analysis of the CICC test facility,the main intention of this dissertation concerns the circuit theory analysis,the mechanical structure and development process,performance of electromagnetic and mechanical,and the cryogenic experiment of the test device.Based on the pertinent literatures both at home and abroad,the CICC test facility has been designed and manufactured successfully,and the preliminary performance testing of the experiments in different operating conditions are carried out after the assembly was completed.Firstly,the system composition of the CICC test facility is introduced in detail,and the circuit characteristics of the superconducting transformer which is the critical component of the facility are analyzed.The key factors and parameters which have much impact on the performance of the transformer have been analyzed and optimized.The electromagnetic characteristics of the superconducting transformer is designed to meet the requirement of the test facility.Secondly,according to the magnetic field distribution of the background magnet,the structures of four low-inductance test samples without joint resistance are designed and optimized.Based on the electromagnetism parameters of the transformer and other subsidiary supported system of the test facility,the integral structure of the CICC test facility has been designed and optimized.The structure of the transformer windings is designed as coaxial-double bobbin-shared plate,the structure of the Cryogenic Dewar of the test facility is designed as two eccentric cylinders.After that,the electromagnetic properties and mechanical properties of the CICC test facility have been analyzed in detail using the theoretical method and the Finite Element Method respectively.The analysis results are great helpful for the structure design of the test facility.An Electromagnetic-Circuit coupled model and an Electromagnetic-Structure coupled model built in ANSYS Multiphysics are successfully used to investigate and evaluate the electromagnetic characterization and mechanical characterization of the test facility under the dynamic operation condition.In this thesis,the electromagnetic force and mutual inductance of the transformer windings results from misalignment during installation are calculated precisely by the means of filament method and Simpson's numerical integration method.In addition,this dissertation also introduces the thermodynamic analysis theories and methods which were used to investigate the complex process of heat transfer of the current lead,superconducting joints,and test sample heater.A thermal fluid-structure model built in ANSYS workbench is used to analyze the thermal performance of the superconducting joints.A steady-state thermal model built in ANSYS workbench is successfully used to research the heating power of the heater which is installed on the test sample.The structure and related parameters of the CICC test facility are also designed and optimized based on the thermal analysis results.Finally,the secondary induced current is measured accurately by the hall sensor and Rogowski coils.And a set of experiments have been completed to test the performance of the CICC test facility under normal temperature and low temperature conditions.The results shows that:the self-inductances of the primary and secondary winding are 3.72H and 8.0 × 10-6H respectively;the secondary induced current amplification factor is between 310 and 320;the resistance of the superconducting joints is about 2n?;The time constant of current decay in the secondary loop is 4000s.All the key parameters are satisfy to the design requirement,and the vacuum system,cryogenic system,quench protection system and data acquisition system and software are reliable and stable during the experiment.