Study On Multi-Physics Co-Simulation Techniques Of Traveling Wave Tube

The traveling wave tube with high power gain and wide frequency band is widely used in radar monitoring,electronic countermeasure,satellite navigation and other fields.The temperature field of TWT in operation changes greatly,which leads to great changes in stress and electrical properties.In the electromagnetic design of TWT,if the stress deformation is not considered,it will be far from the actual situation.Therefore,the multi physical field analysis of TWT in working state can be used as an important means to judge the performance of TWT before fabrication.In addition,the processing and assembly details of TWT can also lead to a large difference from the original design performance.Simulation of the processing and assembly process of key components can predict the working performance and guide the process details.In this paper,based on the multi physical field simulation software ANSYS Workbench and the microwave tube simulation software package MTSS,the multi physical field simulation of the key components and processing technology of TWT is studied.The main work and innovations are as follows:1.Based on the analysis of the structure and material of the electron gun,the multi physical field simulation analysis of the electron gun is completed,the temperature field and stress field of the electron gun are obtained,and the influence of the stress deformation on the performance of the electron gun is analyzed.The multi physical field simulation of electron gun can evaluate the thermal stability and performance change of materials,realize the performance prediction of electron gun,and guide the optimization design.2.Based on the analysis of heat source in helix high frequency structure,the multi physical field analysis of high frequency structure is completed.The accurate simulation of heat source is realized by adding uneven heat loss to the inner surface of helix.By simulating the temperature field and stress field of helix high-frequency structure,and analyzing the influence of structural deformation on the electrical performance of highfrequency system,we can analyze the thermal stability of materials and the change of device performance,realize the performance prediction of high-frequency structure,and guide the structure optimization.3.Based on the study of structure material and heat dissipation of collector,the multi physical field analysis of collector is completed.In order to reduce the thermal deformation,different numbers of fins are added outside the tube,and the structural optimization scheme is determined according to the simulation results to effectively reduce the temperature stress change.4.In order to avoid the poor performance of electron gun caused by the too large change of the distance between the cathode and the heater,a simulation method which can accurately determine the distance between the cathode and the heater of electron gun is established based on the investigation of the assembly process of the cathode assembly of TWT.In the simulation,the thermal analysis of electron gun is completed in ANSYS Workbench,the cathode and heater after deformation repair are introduced into CST,and accurately measure the distance after deformation by the contact judgment function of CST.Modify the model According to the preset assembly tolerance rate can effectively improve the thermal deformation and heater efficiency of the electron gun after assembly.5.Based on the study of graphite heat extrusion process for the high frequency structure,the multi physical field simulation analysis of graphite heat extrusion process for the helix high frequency structure is realized.Due to the different boundary conditions and ambient temperature in the process of heating and cooling,the process of heating and cooling is simulated respectively,and the model of the final state of heating is repaired as the initial model of cooling process to ensure the continuity of the model during heating and cooling process.Obtain the key physical dimension of the deformed model after cooling process,and then reconstruct the deformed model to analyze the influence of stress deformation on the electrical performance.The multi physical field simulation of high frequency structure graphite heat extrusion process can guide the actual process,determine the key process parameters,and predict the performance of high frequency structure after assembly.