倾角对环状热管蒸发器性能的影响

Effect of inclination angle on performance of annular heat pipe evaporator

中文关键词: 环状管两相流  分离式热管  沸腾流型  倾斜管

英文关键词: Annular tube two-phase flow  Separated heat pipe  Boiling flow pattern  Inclined pipes

中文摘要:

      针对生产过程中低品位能量回收，设计了带有环状管蒸发器的不锈钢水工质重力型分离式热管，环状管由31.6 mm管径内管热水加热，环空间隙为15.0 mm，可视化地研究了26 kPa蒸发压力，0~90 °倾斜角度下多个充注率环状管蒸发器的壁温特性。结果表明：该类热管的环状管蒸发器运行时存在一高温区，随倾角增加而扩大；环状管内蒸发侧平均表面换热系数随倾角增大先增后减、再增大，与沸腾流型随角度发生转变有密切关联；与一些相似文献进行了对比，发现环状管蒸发器与普通重力型热管在换热性能均在10~20 °倾角达到极大值，而环状管蒸发器则在90 °时达到了另一极大值。

英文摘要:

      A gravity type separated heat pipe of stainless steel water working medium with annular tube evaporator is designed and developed for low grade energy recovery in the production process, the annular tube is heated by hot water in the pipe diameter of 31.6mm, and the annulus clearance is 15mm.The wall temperature characteristics of annular tube evaporator with multiple filling ratios at 26000 Pa evaporation pressure and inclination of 0~90 ° were studied visually, the results show: The annular tube evaporator of this kind of heat pipe has a superheated zone which expands with the increase of angle; the average surface heat transfer coefficient of the evaporative side of the annular tube increases first, then decreases, and then increases with the increase of the inclination, which is closely related to the boiling flow pattern changes along with the inclination; by comparing with some similar literatures, it is found that the heat transfer performance of annular tube evaporator and ordinary gravity type heat pipe both reaches the maximum at the inclination of 10-20 °, while the annular tube evaporator reaches another maximum at 90 °.