In this work, a new stability method (a mixture of surfactants) was used to preparation 0.1 wt% of hybrid nanofluid including multi-walled carbon nanotubes‑copper oxide (MWCNT-CuO) as a cold fluid in the brazed plate heat exchanger. The four Non-ionic surfactants were used to evaluate the stability of nanofluids. Effects of water and hybrid nanofluid (as cold fluid) on thermal characteristics in the brazed plate heat exchanger were studied. The results display that the stability of hybrid nanofluid with a mixture of two surfactants, including GA and Tween-80, is suitable, and no sedimentation was observed. Also, when the hot fluid is at a consistent temperature of 35 °C and volume flow rate of 6 L/min, the highest increase in the convective heat transfer coefficient of hybrid nanofluid at a volume flow rate of 14.4, 18.9 and 24.4 L/min in comparison with water are 85.56%, 101.25%, and 139.19%, respectively. The significance of the factors and their interactions were verified by using the analysis of variance (ANOVA) with 95% of confidence level (p < 0.05). Finally, the response surface methodology was used to achieve an empirical relationship for the convective heat transfer coefficient and optimization.

在这项工作中，使用一种新的稳定性方法（表面活性剂的混合物）在钎焊板式热交换器中制备0.1 wt％的杂化纳米流体，其中包括多壁碳纳米管-氧化铜（MWCNT-CuO）作为冷流体。四种非离子表面活性剂用于评估纳米流体的稳定性。研究了水和杂化纳米流体（作为冷流体）对钎焊板式换热器热特性的影响。结果表明，杂化纳米流体与两种表面活性剂（包括GA和Tween-80）的混合物的稳定性是合适的，并且未观察到沉淀。同样，当热流体处于35°C的恒定温度和6 L / min的体积流率时，杂化纳米流体的对流传热系数在体积流率分别为14.4、18.9和24时增幅最大。与水相比，4 L / min分别为85.56％，101.25％和139.19％。使用具有95％置信水平的方差分析（ANOVA）验证了这些因素及其相互作用的显着性（p  ＜0.05）。最后，利用响应面方法获得了对流换热系数与优化的经验关系。