Kumar Kodi Rajesh, Shaik Aabid Hussain
Colloids and Polymers Research Group, School of Chemical Engineering, Vellore Institute of Technology Vellore Tamilnadu 632014 India
RSC Adv. 2023 Oct 9;13(42):29536-29560. doi: 10.1039/d3ra05429b. eCollection 2023 Oct 4.
Hybrid nanofluids are considered as an alternative for conventional heat transfer fluids and mono nanofluids due to its remarkable enhancement in thermo-physical properties. However, there are some limitations in achieving the better thermo-physical properties due to the stability of nanoparticles in different base fluids at higher concentration. This work aims at synthesizing, thermo-physical characterization and thermal performance estimation of stable Cu-MXene based hybrid nanofluids using various base fluids at very low volume concentration of Cu and MXene nanostructures. Two step method is employed to prepare Cu-MXene hybrid nanofluids by dispersing the low volume concentration of as prepared Cu and MXene nanostructures (ranging from 0.01-0.05 vol%) containing SDS surfactant in various base fluids such as water, methanol, castor oil and silicon oil. Synthesized mono and hybrid nanofluids shows excellent stability against aggregation up to 7 days as evidenced from higher zeta potential values. Wettability studies conducted using contact angle measurement suggests that the castor oil, methanol and silicon oil based hybrid nanofluids exhibits hydrophilic behavior (showing contact angle less than 90°). Hybrid nanofluids display excellent enhancement in thermal conductivity at very low concentration of nanostructures (more than 70% for methanol based Cu-MXene hybrid nanofluid). Viscosity of the silicone oil based hybrid nanofluids show a remarkable enhancement followed by water, methanol and castor oil based hybrid nanofluids. Thermal conductivity and viscosity of hybrid nanofluids are effectively validated with existing theoretical models. Moreover, specific heat and pumping power of the hybrid nanofluids with respect to volume concentration of nanostructures are determined using the existing theoretical equations. Thermal performance of hybrid nanofluids was successfully estimated using Figure of Merit (FOM) analysis and suggested the better heat transfer fluid for improving the heat transfer performance under laminar and turbulent flow conditions for efficient cooling applications.
混合纳米流体因其热物理性质的显著增强，被视为传统传热流体和单一纳米流体的替代品。然而，由于纳米颗粒在不同基础流体中较高浓度下的稳定性，在实现更好的热物理性质方面存在一些限制。这项工作旨在使用各种基础流体，在极低体积浓度的铜和MXene纳米结构下，合成、进行热物理表征并估计稳定的铜-MXene基混合纳米流体的热性能。采用两步法制备铜-MXene混合纳米流体，即将含有十二烷基硫酸钠表面活性剂的低体积浓度（范围为0.01-0.05体积%）的制备好的铜和MXene纳米结构分散在各种基础流体中，如水、甲醇、蓖麻油和硅油。合成的单一和混合纳米流体在高达7天的时间内表现出优异的抗团聚稳定性，较高的zeta电位值证明了这一点。使用接触角测量进行的润湿性研究表明，基于蓖麻油、甲醇和硅油的混合纳米流体表现出亲水性行为（接触角小于90°）。混合纳米流体在极低浓度的纳米结构下显示出优异的热导率增强（基于甲醇的铜-MXene混合纳米流体增强超过70%）。基于硅油的混合纳米流体的粘度显著增强，其次是基于水、甲醇和蓖麻油的混合纳米流体。混合纳米流体的热导率和粘度通过现有的理论模型得到有效验证。此外，使用现有的理论方程确定了混合纳米流体相对于纳米结构体积浓度的比热容和泵送功率。使用品质因数（FOM）分析成功估计了混合纳米流体的热性能，并表明其是在层流和湍流条件下改善传热性能以实现高效冷却应用的更好的传热流体。
