High-power Gyrotron Thermal Simulation Analysis And Optimization Design

As the frequency of the gyrotron increases,the output power becomes higher,and the stability,reliability,and lifetime of the gyrotron are also required to be higher.The thermal characteristics of the high frequency resonant cavity in the gyrotron is an important factor that directly restricts the performance of the gyrotron.The resonant cavity will produce ohmic losses due to dielectric loss under normal operation.Excessive heat generated by ohmic losses will cause the resonator cavity to deform,and the deformed resonant cavity will affect the resonant frequency of the cavity,reduce the efficiency of wavelet interaction.The Denisov Launcher receives the beam emitted from the high-frequency structure and performs structural processing.Its quality directly determines the performance of the entire mode converter and requires a good heat dissipation design.For the actual output power of the gyrotron,it is necessary to design the water load to absorb the microwave and then measure the value of the output power.In this thesis,the thermal analysis and coupled thermal deformation analysis of the resonant cavity of the gyrotron were performed,and thermal analysis and optimization of Denisov Launchers,and the design and experiment of the water load were simulated.The work of this thesis includes four aspects:1.Brief description of theory related to gyrotron and heat transfer theory and ANSYS softwareThe various components of the gyrotron and the working principles of the gyrotron are researched.The influence of in sufficient heat dissipation on the resonator is mainly analyzed.The basic transfer method and working mechanism of heat transfer theory are briefly described,and the basic theory and related equations of convective heat transfer are deduced.The process of thermal analysis and thermal deformation analysis of ANSYS Workbench software and various boundary conditions,phase change models,and turbulence models were introduced.2.Thermal analysis of gyrotron resonatorThe axial slot is selected for the design of the cavity of the resonant cavity.Thermal analysis of the vertical cavity cavity is performed using ANSYS software to obtain a good slot size.The ANSYS Workbench software was used to perform fluidthermal analysis of the resonator,and the ohmic loss density distribution with non-uniform distribution was obtained by using the recalculated conductivity,and one of them was taken for fluid thermal analysis.The coupled structural mechanics module performs thermal deformation analysis.Through the size of the cavity expansion,the simulation results the variation of the resonant frequency,the distribution of the electric field in the cavity.3.Thermal analysis and optimization of Denisov LaunchersThe thermal analysis of Denisov Launchers was performed using ANSYS Workbench software.In the case where there is no radiation slot at the launcher cutout,the outer wall of the launcher is grooved respectively,and two kinds of vertical slots and spiral slots are selected.The number of slots and the slot width are simulated and a good heat dissipation structure is obtained.The heat sink is added to the notch of the launcher to optimize the design and a better heat dissipation structure is obtained.4 water load design and experimental testingThe HFSS electromagnetic simulation software was used to simulate and optimize the water load.By optimizing the tilt angle and the thickness of the window,a water load that meets the requirements was designed.By testing the power of the input and output,a comparison is made to verify the absorption capacity of the water load.