| High magnetic fields play a crucial role in the progress of science and technology,not only promoting many significant scientific discoveries,but also promoting the emergence of many new technologies.The generation and application research of ultra-high magnetic fields not only provide strong technical support for high-end equipment manufacturing,scientific facilities that require extreme conditions,the development of biomedicine,the manufacturing of defense and military equipment,and high-precision scientific instruments,but also have a profound impact on the development of agricultural applications.However,China’s high field superconducting magnet technology still lags behind foreign countries in terms of key technologies and processes due a variety of reasons for a long time.Most high-end instruments and equipment still rely on imports from abroad,which greatly limits the development of China’s scientific research.The purpose of this research project is to explore the design and manufacture of skeletonless superconducting magnets for scientific research purposes,and to reduce the quench risk of epoxy resin impregnated superconducting magnets by improving the process,insulating support structures,etc.The research results can lay a theoretical and data foundation for the mechanical performance analysis of superconducting magnets,in order to achieve the comprehensive localization of high field superconducting magnets,catch up with and even surpass foreign research progress,So that China’s development in the field of high-field superconducting magnets is no longer constrained by others.The main research contents and results are as follows:(1)According to the target requirements,based on the main technical requirements,machining performance,and economic benefits of superconducting magnets,this paper innovatively adopts a frameless structure design,and decides to use low-temperature superconducting Nb Ti circular wires to wound superconducting magnet coils.Based on the rated working current and uniformity requirements of the magnet,the electromagnetic analysis and design of the magnet were carried out,and a 3+2 spiral tube coil configuration was determined.The 2D magnetic field characteristics of the spiral tube coil structure under the rated current were simulated and analyzed using ANSYS finite element analysis software,and accurate magnetic field distribution information was obtained.The results showed that the physical parameters of the shimming coil met the design requirements.Through numerical analysis and three-dimensional simulation research on the electromagnetic stress suffered by the superconducting magnet coil during operation,it is concluded that the maximum electromagnetic stress suffered by the magnet is 86.92 MPa,which is far less than its allowable extreme value,and the magnet will not be damaged.(2)Using a GM refrigerator to cool the superconducting coil using conductive cooling to bring the magnet to normal operating temperature,we innovatively proposed a structural design scheme for the skeletonless superconducting coil,and successfully completed the entire process of processing and manufacturing,verifying the feasibility of the scheme.(3)A winding and vacuum pressure impregnation platform based on the skeletonless design of superconducting magnet coils was built,and the VPI process flow and process parameters for Nb Ti superconducting skeletonless coils were optimized and formulated to meet the requirements for the production of high-field superconducting magnet coils.The mechanical properties of the modified epoxy resin insulation system were studied,and the skeleton free superconducting magnet coils were impregnated and cured with 11.2%wt Al N-IR3 epoxy resin system to obtain high-quality skeleton free superconducting magnet coils.(4)Finally,through experimental research and analysis of the mechanical properties of the coil after immersion at low temperatures and room temperature,the results show that the shear strength of the coil sample obtained after vacuum pressure immersion at 77 K is108.09 MPa,which is far superior to the limit stress value borne by the superconducting coil during normal operation at low temperatures.Through the above research work,it is proved that the designed skeletonless superconducting magnet coil structure can meet the needs of practical engineering,and it is also proved that the optimized vacuum pressure impregnation curing process can be applied to the processing and manufacturing of superconducting magnet coils in practical engineering... |
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