歧管式微通道(MMC)热沉具有热阻小、结构紧凑、冷却液流量小、流速低、沿着流动方向温度分布均匀等优点,但其小尺寸所产生的较大压降却增加了泵功的损耗.本文研究了表面活性剂添加对其阻力特性的影响,实验选用了纯度为95%的阴离子表面活性剂十二烷基硫酸钠(SDS)和纯度为98%的新型绿色非离子表面活性剂烷基多糖苷(APG)作为减阻添加剂,浓度分别为100和300mg·kg^-1,结果表明阻力减小率与流速和温度有关.在层流区内减阻效果不是特别明显;但是当流体进入紊流区后阻力减小率开始明显增大,尤其是进入充分发展的紊流区后减阻效果大大加强.此外,温度的提升也可增加阻力减小率,但添加SDS后减阻效果的改善却不及APG.通过对两种不同类型表面活性剂的实验比较,发现温度较高时APG比SDS具有更住的减阻效果.
The manifold micro-channel (MMC) heat sink has such advantages as low thermal resistance, compact structure, small amount of coolant, low flow rate, uniform temperature distribution along the flow direction, but high pressure drop is required due to narrow channel width and increased pump power. This article investigates the influence of surfactant on flow characteristics in a MMC. An anionic surfactant sodium dodecyl sulfate (SDS, 95% purity grade) 100 mg ·kg^-1 aqueous solution and a new type of green non-ionic surfactant of alkyl polyglycoside (APG, 98% purity grade) 300 mg· kg^-1 aqueous solution were used separately as working fluid. The results demonstrated that drag reduction depended on flow velocity and temperature. In laminar flow regime, the drag reduction effect was not obvious; but when the fluid entered turbulent flow regime, drag reduction was enhanced notably and especially in fully developed turbulent flow regions. Furthermore, temperature rise could also enhance drag reduction, but the enhancement of drag reduction due to adding SDS was less than APG. By comparing the drag reduction effect of SDS and APG through experiments, it was concluded that APG has better drag reduction effect than SDS at higher temperatures.