Abstract The present research investigates the heat transfer enhancement by adding alumina nanoparticle to water, Ethylene glycol, and 1-ethyl-3-methylimidazolium ethyl sulfate [EMIM][EtSO4] ionic liquid (called ionic liquid-based nanofluid or INf in synonym) as a base fluid. A horizontal tube with constant heat flux was modeled in two-dimensional geometry with a diameter and length of 4.0 mm and 6.0 m, respectively. Al2O3 (20 nm in diameter) nanoparticles added to the base fluid in 0.5, 1.0 and 2.5 weight fraction percent. Various factors such as Reynolds number, nanofluids concentration, type of base fluid, and especially fluid inlet temperature studied in this research. Impressive results observed with variation in fluid temperature which for the temperature below room temperature (278.15 K) IL-based nanofluid shows greater heat transfer coefficient than water and Ethylene glycol-based nanofluids because of its higher thermal conductivity and viscosity at a lower temperature. And also, by adding nanoparticles to the base fluids and increasing the concentration of nanofluids, the heat transfer coefficient increased. Both the maximum heat transfer coefficient and heat transfer enhancement observed for IL-based nanofluid at 2.5 wt% concentration of nanoparticle. Finally, a correlation proposed for Nu number that satisfies for all studied nanofluids with R2 = 0.971 and AREP = 7.9%.

中文翻译：

---

研究各种因素对离子液体、乙二醇和水作为水平管中 Al2O3 纳米流体基液对流传热性能的影响：数值研究

摘要 本研究通过在水、乙二醇和 1-乙基-3-甲基咪唑乙基硫酸盐 [EMIM][EtSO4] 离子液体（称为基于离子液体的纳米流体或同义词 INf）中加入氧化铝纳米颗粒来增强传热效果。一种基液。具有恒定热通量的水平管在二维几何中建模，直径和长度分别为 4.0 mm 和 6.0 m。Al2O3（直径为 20 nm）纳米颗粒以 0.5、1.0 和 2.5 重量百分比添加到基液中。本研究中研究了各种因素，例如雷诺数、纳米流体浓度、基液类型，尤其是流体入口温度。随着流体温度的变化观察到令人印象深刻的结果，对于低于室温的温度 (278. 15 K) 基于 IL 的纳米流体显示出比基于水和乙二醇的纳米流体更大的传热系数，因为它在较低温度下具有更高的热导率和粘度。而且，通过在基液中添加纳米粒子并增加纳米流体的浓度，传热系数增加。在纳米颗粒浓度为 2.5 wt% 时，对于基于 IL 的纳米流体观察到的最大传热系数和传热增强。最后，为 Nu 数提出的相关性满足所有研究的纳米流体，R2 = 0.971 和 AREP = 7.9%。传热系数增加。在纳米颗粒浓度为 2.5 wt% 时，对于基于 IL 的纳米流体观察到的最大传热系数和传热增强。最后，为 Nu 数提出的相关性满足所有研究的纳米流体，R2 = 0.971 和 AREP = 7.9%。传热系数增加。在纳米颗粒浓度为 2.5 wt% 时，对于基于 IL 的纳米流体观察到的最大传热系数和传热增强。最后，为 Nu 数提出的相关性满足所有研究的纳米流体，R2 = 0.971 和 AREP = 7.9%。