The startup behaviors of evaporation heat transfer in a trapezoidal groove are experimentally studied by using an axial heat pipe with trapezoidal grooves. The effects of heat load and inclined angles on the evaporation startup behaviors are analyzed and discussed. The startup regime diagram is provided to quantitatively describe the behaviors of evaporation heat transfer based on the Weber number and Bond number. The results indicate that, only the gradual startup is observed for the evaporation heat transfer in trapezoidal grooves, however the gradual startup and overshoot startup is experienced in sequence in the tilt condition as the heat load increases. The appearance of evaporation startup regime transition from the gradual startup to overshoot startup is induced by the evaporation regime transition from the fin-film evaporation to the corner-film evaporation inside the evaporator section. The gradual startup occurs for a small Weber number and the overshoot startup occurs for a large Weber number. Increase in Bond number introduces a larger transition Weber number for the startup regime variation of evaporation heat transfer in a trapezoidal groove. Interestingly, the occurrence of the temperature overshoot of few Celsius degrees can be observed to verify whether the grooved heat pipe is in a horizontal position.

利用梯形槽轴向热管实验研究了梯形槽内蒸发传热的启动行为。分析和讨论了热负荷和倾斜角度对蒸发启动行为的影响。提供启动机制图以定量描述基于韦伯数和邦德数的蒸发传热行为。结果表明，梯形槽内蒸发传热仅观察到逐渐启动，而在倾斜条件下，随着热负荷的增加，依次经历了逐渐启动和超调启动。蒸发启动状态从逐渐启动到过冲启动的过渡是由蒸发器部分内从翅片膜蒸发到角膜蒸发的蒸发状态过渡引起的。韦伯数较小时为渐进式启动，韦伯数较大时为过冲启动。Bond 数的增加为梯形槽中蒸发传热的启动状态变化引入了更大的过渡韦伯数。有趣的是，可以观察到几摄氏度的温度超调的发生，以验证带槽的热管是否处于水平位置。Bond 数的增加为梯形槽中蒸发传热的启动状态变化引入了更大的过渡韦伯数。有趣的是，可以观察到几摄氏度的温度超调的发生，以验证带槽的热管是否处于水平位置。Bond 数的增加为梯形槽中蒸发传热的启动状态变化引入了更大的过渡韦伯数。有趣的是，可以观察到几摄氏度的温度超调的发生，以验证带槽的热管是否处于水平位置。