Thermal Analysis Of High Power Gyrotron

Gyrotron is a new vacuum electronic devices based on the principle of free electron cyclotron resonance maser theory. Because of its advantages of high-power, high efficiency, wide bandwidth and so on, gyrotron has broad application prospect in radar, electronic warfare, communications, controlled thermonuclear fusion, high-power microwave weapons, new materials, medical and other fields. In recent years, more and more high gyrotron output power, has made millimeter waveband hundreds of kilowatts of continuous wave power and gigawatt pulsed power. With the increase of gyrotron output power, the design of high power gyrotron cooling system is also facing great challenges. Because the gyrotron materials have dielectric loss, there is a part of power will be dissipated in the form of heat when gyrotron work. If there is no effective design for the cooling system of the gyrotron, especially in high power operation, the gyrotron will be damaged due to high temperature. Therefore, heat dissipation research to improve the stability, reliability and life of the gyrotron has great significance.This paper mainly studies the temperature distribution and thermal deformation of the electron gun cathode and the high frequency resonant cavity of the gyrotron. The main contents of this paper are as follows:1. Briefly introduces the theory of gyrotron and the ANSYS softwareIt is a brief introduction for basic theory of the gyrotron electron gun and resonant cavity, analyzes the influence of some parameters on the electron gun and the resonant cavity; the basic theory of heat transfer and the main heat transfer mode(heat conduction, convection, radiation) made a presentation, the differential equations of convective heat transfer are derived; introduction to the main functions of ANSYS software and the process steps of thermal analysis.2. The thermal and structural analysis of gyrotron electron gunThe electron gun is the "heart" of the high power gyrotron, which provides the electron beam for the beam wave interaction. The quality of the electron gun directly affects the reliability and life span of the gyrotron. In this paper, simulating and modeling of electron gun by use of ANSYS software, and then to analyze its temperature distribution and deformation. Mainly through increasing the filament heating power, optimize the number and arrangement of filaments, slitting the support tube, etc, to make the surface temperature of the electron gun reaches the emission requirements. Optimizing eventually make emission band surface temperature above 1000℃,the surface temperature difference below 1℃. Then analyze the deformation of electron gun cathode.3. The thermal and structural analysis of gyrotron resonant cavityUsing ANSYS software to simulate the thermal characteristics of the gyrotron resonant cavity, comparative analysis the temperature distribution results of uniform and non-uniform heat flux loaded. And through optimizing resonant cavity grooved ways and size to design a good cooling structure. Then the influence of cavity deformation on the resonant mode and frequency were analyzed by HFSS software.