模拟冷却水中Al2O3纳米颗粒分散条件的优化

摘要

Nanofluids were prepared using Al2 O 3 nanoparticles in simulated cooling water.The stability of nanofluids was characterized by zeta potential.The effect of dodecyl benzene sulfonate (SDBS)concentration, sonication time,solution pH on the stability of nanofluids and the optimum conditions were researched in this paper.Results of single factor experiments revealed that the absolute value of zeta potential ζ of nanoparticles increased first but then decreased with the increase of the SDBS concentration,sonication time and pH value. Based on the preliminary experimental results,the box-behnken design (BBD)model of response surface meth-odology was applied to optimize nanoparticle dispersion conditions in simulated cooling water.Results showed that the contribution of SDBS concentration to ζ was maximum,than the solution pH value;the interactions between SDBS concentration and pH,sonication time and pH were relatively obvious;the optimal condition to obtain stable Al2 O 3 nanofluid achieved from BBD model was SDBS at weight concentration of 0.339%,ultrason-ic time 61 min,pH value 8.05,and the predicted value of ζ was 50.8 mV.The experimental value of ζ at the optimal condition was 50.6 mV,which was very close to the predicted value.%在模拟冷却水中添加 Al2 O 3纳米颗粒制备纳米流体,用 zeta 电位表征纳米流体的稳定性.研究了十二烷基苯磺酸钠(SDBS)浓度、超声处理时间、溶液 pH 值对纳米流体稳定性的影响及最佳优化条件.单因素实验结果表明,随着 SDBS 浓度、超声处理时间、溶液 pH 值的增加,纳米颗粒 zeta 电位绝对值ζ均先增加后减小.在此基础上,运用响应曲面法中的Box-Behnken 设计(BBD)模型对纳米颗粒分散条件进行优化,结果显示,SDBS 浓度对 zeta 电位的贡献最大,其次为溶液 pH 值；SDBS 浓度与 pH 值、超声时间与 pH 值两两之间的交互作用较明显；BBD 模型给出模拟冷却水中纳米颗粒分散稳定性的优化条件为 SD-BS 浓度0．339％(质量分数),超声时间61 min,pH 值8．05,预测ζ为50．8 mV,实验测得优化条件下ζ为50．6 mV,与预测值接近.