Research On Measurement Technique And Thermal Analysis Of TWT’s Main Components

Traveling wave tube (TWT) is a vacuum electron tube, which is used as a wideband high power microwave source and microwave signal amplifier. Traveling wave tube has an irreplaceable position in many industries, such as radar system, electronic warfare, and satellite communications. The temperature of the TWT is very high when it works. So if the local temperature is too high, the TWT may be damaged and the service life of TWT will be shortened seriously. As the performance indexes of TWT are improving, the TWT thermal optimization design is becoming more and more significant. The slow wave structure and the collector are the heating worst parts of the TWT, so this paper focused on their thermal analysis, the surface measurement technology and an estimation method for inner temperature distribution of them.The thermal states of slow wave structure and collector was analyzed based on finite element analysis software ANSYS in the paper. Firstly the finite element models of slow wave structure and collector were established. Secondly the thermodynamic boundary conditions were loaded into the models. At last the temperature distribution cloud pictures and heat flux vector pictures were obtained through ANSYS finite element simulations.A TWT multi-point temperature measurement system for the surface of key components was developed in the paper, which used 16 thermocouples as the temperature sensors. In the system, the software would display the multi-point temperature curves in screen and store the data in MySQL database system. This system would help TWT researcher observe the thermal state of TWT surface temperature filed. Two kinds of TWT’s slow wave structure and collector were measured in the paper, and the temperature distribution cloud pictures of their surfaces were obtained based on 2-D interpolation algorithm. The results showed that the input signals of different frequencies would affect the the temperature distribution of slow wave structure and collector.An estimation method for inner temperature distribution of slow wave structure and collector is proposed. This estimation method is based on ANSYS 3-D thermal model and TWT body multi-point temperatures, without placing temperature sensors inside the TWT. After the preliminary numerical verification, this method showed a good feasibility and accuracy.