Purpose

This study aims to enhance heat transfer efficiency while minimizing friction factor and entropy generation in the flow of Nickel zinc ferrite (NiZnFe₂O₄) nanoparticles suspended in multigrade 20W-40 motor oil (as specified by the Society of Automotive Engineers). The investigation focuses on the effects of the melting process, nonspherical particle shapes, thermal dispersion and viscous dissipation on the nanofluid flow.

Design/methodology/approach

The fundamental governing equations are transformed into a set of similarity equations using Lie group transformations. The resulting set of equations is numerically solved using the spectral local linearization method. Additionally, sensitivity analysis using response surface methodology (RSM) is conducted to evaluate the influence of key parameters on response function.

Findings

Higher dispersion reduces entropy production. Needle-shaped particles significantly enhance heat transfer by 27.65% with melting and reduce entropy generation by 45.32%. Increasing the Darcy number results in a reduction of friction by 16.06%, lower entropy by 31.72% and an increase in heat transfer by 17.26%. The Nusselt number is highly sensitive to thermal dispersion across melting and varying volume fraction parameters.

Originality/value

This study addresses a significant research gap by exploring the combined effects of melting, particle shapes and thermal dispersion on nanofluid flow, which has not been thoroughly investigated before. The focus on practical applications such as fuel cells, material processing, biomedicine and various cooling systems underscores its relevance to sectors such as nuclear reactors, tumor treatments and manufacturing. The incorporation of RSM for friction factor analysis introduces a unique dimension to the research, offering novel insights into optimizing nanofluid performance under diverse conditions.

中文翻译：

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多级机油基纳米流体的熵优化：具有颗粒形状和色散效应的光谱和灵敏度分析

 目的

本研究旨在提高传热效率，同时最大限度地减少悬浮在多级 20W-40 机油（按照汽车工程师协会的规定）中的镍锌铁氧体 (NiZnFe ₂ O ₄ ) 纳米粒子流动中的摩擦系数和熵产生。研究重点是熔化过程、非球形颗粒形状、热分散和粘性耗散对纳米流体流动的影响。

设计/方法论/途径

使用李群变换将基本控制方程转换为一组相似方程。使用谱局部线性化方法对所得方程组进行数值求解。此外，还使用响应面法（RSM）进行敏感性分析，以评估关键参数对响应函数的影响。

 发现

较高的色散减少了熵的产生。针状颗粒使熔融传热显着增强27.65%，并减少熵产生45.32%。增加达西数会导致摩擦减少 16.06%，熵降低 31.72%，传热增加 17.26%。努塞尔数对熔化过程中的热分散和变化的体积分数参数高度敏感。

 原创性/价值

这项研究通过探索熔化、颗粒形状和热分散对纳米流体流动的综合影响，弥补了一个重大的研究空白，而这在以前尚未得到彻底研究。对燃料电池、材料加工、生物医学和各种冷却系统等实际应用的关注强调了其与核反应堆、肿瘤治疗和制造等领域的相关性。将 RSM 纳入摩擦系数分析为研究引入了独特的维度，为在不同条件下优化纳米流体性能提供了新颖的见解。