Abstract: The experiments on heat transfer characteristics of the start-up and steady operation processes of pulsating heat pipe were conducted using three working fluids at various inclination angles and heat inputs. Water，methanol，and aqueous methanol were used as working fluid with 50% fill ratio. The characteristics were compared and analyzed between aqueous methanol，water，methanol in the start-up and steady operation processes. The type of start-up for aqueous methanol was gradual start-up at low heat inputs and different inclination angles. Start-up time span of aqueous methanol was longer than that of methanol，but shorter than that of water. In a steady operation process，the temperature of aqueous methanol in heating section was lower than that of methanol，and fluctuation of temperature was larger. Aqueous methanol showed the best thermal performance among them at low and medium heat inputs. The minimum thermal resistances of aqueous methanol were 0.38℃/W and 0.3℃/W at the angle 45°and 90°，respectively.

Key words: aqueous methanol, methanol, pulsating heat pipe, inclination angle, heat transfer performance

摘要： 以体积分数为50%的甲醇水溶液为工质，充液率为50%，对不同倾角和加热功率条件下环路脉动热管的启动性能和稳定运行时的传热性能进行了实验研究。对比分析了甲醇水溶液、无水甲醇和水的传热效果，探讨了甲醇水溶液与水、无水甲醇在启动过程中启动时间、启动温度以及稳定运行时传热热阻、热冷端温差的变化特点。结果表明，在低加热功率条件下，甲醇水溶液45°和90°倾角下的启动方式均为温度渐变型，甲醇水溶液的启动时间比无水甲醇长，但比水短。稳定运行时，甲醇水溶液在90°倾角下加热段温度低于甲醇，且波动较大。在低、中加热功率条件下，甲醇水溶液传热性能优于水和无水甲醇，甲醇水溶液在45°和90°倾角下的最小热阻值分别为0.38℃/W和0.3℃/W。

关键词: 甲醇水溶液, 甲醇, 脉动热管, 倾角, 传热性能