Quartz lamp heaters and hypersonic wind tunnel are currently applied in thermal assessment of heat resistant materials and surface of aircraft. However, it is difficult to achieve precise heat flux distribution by quartz lamp heaters, while enormous energy is required by a large scale hypersonic wind tunnel. Electron beam can be focused into a beam spot of millimeter scale by an electromagnetic lens and electron-magnetically deflected to achieve a rapid scanning over a workpiece. Moreover, it is of high energy utilization efficiency when applying an electron beam to heat a metal workpiece. Therefore, we propose to apply an electron beam with a variable speed to establish a novel method to realize various non-uniform heat flux boundary conditions. Besides, an electron beam thermal assessment equipment is devised. To analyze the feasibility of this method, an approach to calculate the heat flux distribution formed by an electron beam with variable-speed scanning is constructed with beam power, diameter of the beam spot and dwell duration of the electron beam at various locations as the key parameters. To realize a desired non-uniform heat flux distribution of the maximum gradient of 1.1 MW/m³, a variable-speed scanning strategy is constructed on basis of the conservation of energy. Compared with the desired heat flux, the maximum deviation of the scanned heat flux is 4.5% and the deviation in the main thermal assessment area is less than 3%. To verify the method, taking the time-average scanned heat flux as the boundary condition, a heat transfer model is constructed and temperature results are calculated. The experiment of variable-speed scanning of an electron beam according to the scanning strategy has been carried out. The measured temperatures are in good agreement with the predicted results at various locations. Temperature fluctuation during the scanning process is analyzed, and it is found to be proportional to the scanned heat flux divided by volumetric heat capacity, which is applicable for different materials up to 3.35 MW/m². This study provides a novel and effective method for precise realization of various non-uniform heat flux boundary conditions.

石英灯加热器和高超音速风洞目前应用于耐热材料和飞机表面的热评估。然而，石英灯加热器难以实现精确的热通量分布，而大型高超声速风洞需要巨大的能量。电子束可以通过电磁透镜聚焦成毫米级的束斑，并通过电磁偏转实现对工件的快速扫描。此外，在应用电子束加热金属工件时，能量利用效率高。因此，我们建议应用变速电子束来建立一种新方法来实现各种非均匀热通量边界条件。此外，设计了电子束热评估设备。为分析该方法的可行性，以电子束功率、束斑直径和电子束在不同位置的停留时间为关键，构建了一种变速扫描计算电子束形成的热流分布的方法。参数。实现所需的最大梯度为 1.1 MW/m 的非均匀热通量分布³，在能量守恒的基础上构建了变速扫描策略。与期望热通量相比，扫描热通量的最大偏差为4.5%，主要热评估区域的偏差小于3%。为验证该方法，以时间平均扫描热通量为边界条件，构建传热模型并计算温度结果。根据扫描策略进行了电子束变速扫描实验。测得的温度与不同位置的预测结果非常吻合。分析了扫描过程中的温度波动，发现它与扫描热通量除以体积热容量成正比，适用于高达3.35 MW/m的不同材料² . 该研究为精确实现各种非均匀热通量边界条件提供了一种新颖有效的方法。