不同温度下纳米流体对微槽群热沉毛细性能的强化差异研究

Capillary Performance Differences ofFe_(3)O_(4) Water-based Nanofluids to Microgrooves Heat Sinks Under Different Temperatures

基于一维的自适应理论,采用经典的毛细上升法,在室温、40℃、60℃情况下比较分析温度对Fe_(3)O_(4)水基纳米流体强化微槽群热沉毛细性能的影响。结果表明:3个温度下,纳米流体所产生的强化效果随颗粒体积分数的变化规律是一致的,并存在统一的最佳体积分数。纳米流体对热沉毛细性能的平均强化比例随温度的提高呈现先减小后增大的趋势。低体积分数下,提高温度有利于纳米流体增强毛细压,其强化比例在60℃情况下可超过20%,但渗透率的增大比例会持续下降;高体积分数下,温度提升会同时抑制其增强毛细压与渗透率。根据分析,这应与温度升高致使切向流动与颗粒聚集程度改变有关。

Based on accommodation theory,the capillary rise method was used to study the enhanced effect differences of different nanoparticle volume fraction and nanofluid temperatures on microgrooves heat sinks.The research results showed that under different temperature conditions,the enhanced effect produced by the nanofluid with the change of particle volume fraction was consistent with the room temperature and 40℃,and there was an optimal volume fraction,and the optimal value was reached at a volume fraction of 0.00375%.The average increment percentage to the capillary performance of the heat sink decreased first and then increased with the increase of temperature.At low volume fractions,increasing the temperature would help nanofluids enhance capillary pressure.The increment percentage exceeded 20% at 60℃,but the increase rate in permeability continued to decrease;at high volume fractions,the increase in temperature would weaken the increment in capillary and permeability.According to the analysis,this may be related to the enhanced tangential flow in the cross-sectional area of microgrooves and the degree of particle aggregation.