Abstract:

Surface tension is one of the important factors that influences the behaviors of the working fluid bubbles, such as generation, pulsation split and merge. Furthermore, the heat transfer performance of pulsating heat pipe (PHP) is affected. Three concentration solutions 0.001%, 0.005% and 0.009% were configured using sodium dodecyl benzene sulfonate (SDBS) as solute and deionized water as base fluid. The surface tension of water was decreased by 42.2% after addition of 0.005% SDBS, while little change of the specific heat, density and viscosity. Both the start-up and heat transfer performance of PHP were test with the concentration solutions under different heating power input. The experimental results indicated that SDBS can reduce the start-up time of the pulsating heat pipe. Start-up time of 0.001% solution was the shortest with the heating power input no more than 90 W. Differently, the addition of SDBS has little effect on the start-up time under high heating power input. At steady working station, the heat transfer performance of PHP was improved by adding SDBS.

Key words: heat and mass transfer, pulsating heat pipe, surface tension, start-up time, heat transfer performance

摘要：

脉动热管工质气泡的产生、脉动、分裂、合并是脉动热管运行特性的重要影响因素。而表面张力是气泡产生、脉动、分裂、合并运行规律的重要影响参数。以表面活性剂十二烷基苯磺酸钠(sodium dodecyl benzene sulfonate,SDBS)为溶质,以去离子水为基液,配制了质量分数为0.001%、0.005%和0.009%的3种溶液。测试发现表面活性剂的添加对水的表面张力改变较大,浓度为0.005%时表面张力降低了42.2%,而对水的比热容、密度、黏度影响较小。在自行设计搭建的脉动热管传热性能实验台上,对比实验测试了在不同浓度、不同加热功率下表面张力对脉动热管启动及传热性能的影响规律。研究结果发现:表面活性剂可以减小脉动热管启动时间,在低加热功率条件下(≤90 W),0.001% SDBS水溶液的启动时间最快,最快比水快了11.2%;而在大功率加热条件下,SDBS的添加对启动时间影响较小。而且表面活性剂可以改变脉动热管传热性能,使其热阻出现不同程度的减小。

关键词: 传热传质, 脉动热管, 表面张力, 启动时间, 传热性能