For a traditional collector of an S-band backward-wave oscillator, the affected area due to bombardment by energetic electrons was experimentally measured, and the power per unit area as thermal loading for a 700 keV and 7 kA beam with 50 ns duration was calculated. By using an ANSYS-APDL package, the 10 to 100 Hz repetitive operation results of temperature history and distribution of the collector were typically presented at convective coefficient of 7 000 W/(m2 ? ℃) and water temperature of 20℃. The relationship between the equilibrium temperature and convective coefficient for different pulse repetition rate was also obtained. In addition, the cooling flow rate corresponding to different convective coefficient was given.%针对一种返波管常规收集极,实测了电子束在收集极内表面的有效作用面积,以电子能量700keV、束流7 kA和脉宽50 ns为例,计算了单脉冲时的热功率沉积和平均热流密度.利用通用有限元软件ANSYS,采用脉冲热源加载的方式,在对流换热系数7000 W/(m2·℃)、水温20℃的条件下,得到了收集极10～100 Hz运行时温度历史曲线及温度分布,并比较了不同重复频率下收集极平衡温度与对流换热系数的关系.如果以300℃为气体发生显著热脱附的温度阈值,对流换热系数为7000 W/(m2·℃)时,能够满足重复频率50 Hz以下运行,而到100 Hz时,对流换热系数则需增加到104 W/(m2·℃).根据流体计算公式,给出了不同对流换热系数对应的水流流速.
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