行波管热子功率若干工程性问题的研究

Study on Some Engineering Problems of Heater Power in Traveling Wave Tubes

广泛应用于行波管的M型阴极的寿命对工作温度变化十分敏感,长期工作时热子电阻会由于高温烧蚀而升高,使阴极热子组件加热功率缓慢偏离设计值,进而改变阴极电流,严重时可导致行波管失效。依据ANSYS仿真和测试结果对行波管用电子枪的阴极热子组件进行了热力学性能研究,分析了电子发射的冷却效应对光学测温、热力学仿真及行波管测试的影响;结合电子枪的应用环境,分别在恒压和恒流供电模式下提出了阴极热子组件寿命的评估方法。研究结果表明,为维持阴极表面工作温度恒定,需要阴极热子组件额外提供约3.3%~8.9%的功率来补偿冷却效应的影响。恒压供电模式下热子电阻升高28.9%时,阴极热子组件寿命终结,恒流供电模式下热子电阻升高23.7%时,阴极热子组件寿命终结。

The life of M-type cathodes widely used in traveling wave tubes(TWTs)is very sensitive to temperature change.During long-term operation,the resistance of the heater increases due to high operating temperature,which causes the heating power slowly deviate from the design value,thereby resulting in cathode current change,and the severe cathode current change can lead to the failure of TWTs.Based on ANSYS simulation and test results,the thermodynamic performance of the cathode heater component of electron gun for TWT is studied,and the effects of the cooling effect of electron emission on optical temperature measurement,thermodynamic simulation and TWT test are analyzed.Considering the application environment of electron guns,evaluation methods for the life of cathode heater components are proposed under constant voltage mode and constant current mode respectively.The research results indicate that in order to maintain a constant working temperature on the cathode surface,an additional power of 3.3%~8.9%is required to compensate for the cooling effect.Under constant voltage power supply mode,the life of the cathode heater component ends when the heater resistance increases by 28.9%;while under constant current power supply mode,the life of the cathode heater component ends when the heater resistance increases by 23.7%.