Abstract It has been more than two decades since the discovery of nanofluids-mixtures of common liquids and solid nanoparticles less than 100 nm in size. As a type of colloidal suspension, nanofluids are typically employed as heat transfer fluids due to their favorable thermal and fluid properties. There have been numerous numerical studies of nanofluids in recent years (more than 1000 in both 2016 and 2017, based on Scopus statistics). Due to the small size and large numbers of nanoparticles that interact with the surrounding fluid in nanofluid flows, it has been a major challenge to capture both the macro-scale and the nano-scale effects of these systems without incurring extraordinarily high computational costs. To help understand the state of the art in modeling nanofluids and to discuss the challenges that remain in this field, the present article reviews the latest developments in modeling of nanofluid flows and heat transfer with an emphasis on 3D simulations. In part I, a brief overview of nanofluids (fabrication, applications, and their achievable thermo-physical properties) will be presented first. Next, various forces that exist in particulate flows such as drag, lift (Magnus and Saffman), Brownian, thermophoretic, van der Waals, and electrostatic double layer forces and their significance in nanofluid flows are discussed. Afterwards, the main models used to calculate the thermophysical properties of nanofluids are reviewed. This will be followed with the description of the main physical models presented for nanofluid flows and heat transfer, from single-phase to Eulerian and Lagrangian two-phase models. In part II, various computational fluid dynamics (CFD) techniques will be presented. Next, the latest studies on 3D simulation of nanofluid flow in various regimes and configurations are reviewed. The present review is expected to be helpful for researchers working on numerical simulation of nanofluids and also for scholars who work on experimental aspects of nanofluids to understand the underlying physical phenomena occurring during their experiments.

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纳米流体流动建模与仿真的最新进展——第一部分：基础与理论

摘要 自从发现纳米流体——尺寸小于 100 nm 的普通液体和固体纳米粒子的混合物以来，已经过去了二十多年。作为一种胶体悬浮液，纳米流体由于其良好的热和流体特性通常被用作传热流体。近年来，对纳米流体进行了大量数值研究（根据 Scopus 统计，2016 年和 2017 年均超过 1000 项）。由于在纳米流体流动中与周围流体相互作用的纳米颗粒尺寸小且数量多，因此在不产生极高计算成本的情况下捕获这些系统的宏观尺度和纳米尺度效应一直是一项重大挑战。为了帮助了解纳米流体建模的最新技术并讨论该领域仍然存在的挑战，本文回顾了纳米流体流动和传热建模的最新进展，重点是 3D 模拟。在第一部分，将首先介绍纳米流体（制造、应用及其可实现的热物理特性）的简要概述。接下来，讨论了颗粒流中存在的各种力，例如阻力、升力（马格努斯和萨夫曼）、布朗力、热泳力、范德华力和静电双层力，以及它们在纳米流体流动中的重要性。然后，回顾了用于计算纳米流体热物理性质的主要模型。接下来将描述纳米流体流动和传热的主要物理模型，从单相到欧拉和拉格朗日两相模型。在第二部分，将介绍各种计算流体动力学 (CFD) 技术。接下来，回顾了各种状态和配置下纳米流体流动的 3D 模拟的最新研究。本综述有望对从事纳米流体数值模拟的研究人员以及从事纳米流体实验方面工作的学者有所帮助，以了解他们实验中发生的潜在物理现象。