Investigations on Heat-Transfer Fluids by means of Computer Simulations: Fokus on Ionic Liquids and Ionanofluids

本课题是利用计算机模拟对传热流体进行理论研究。在实际应用中，从冷却装置到太阳能收集，HTFs的热传导和热容等热物理性质具有至关重要的意义。对HTFs进行建模可以更深入地了解底层机制，例如在原子和分子水平上的热传导。本文使用的非平衡分子动力学（NEMD）方法，通过显式建模的热梯度，提供了研究耦合效应的机会，如热泳动。详细了解其作用机理及其对分子结构、组成和热物理性质的影响，对HTFs的有目的设计至关重要。本文主要研究离子液体（ILs）和离子液体中纳米颗粒的悬浮液，即离子流体或纳米颗粒增强的ILs (NEILs)，简称HTFs。研究重点1关注纯il和不同阴离子或阳离子类型对il的影响，以及杂质（如水、氯离子或有机溶剂等）对其热物理性质的影响。研究重点2是neil及其与纳米粒子的相互作用所产生的额外效应和机制，实验表明，neil与纳米粒子的相互作用导致了导热系数的显著增加。

The project is about theoretical investigations on heat-transfer fluids (HTFs) by means of computer simulations. In practical applications, from cooling devices to solar energy collection, the thermophysical properties of the HTFs, like heat conduction and heat capacity, are of crucial significance. Modeling the HTFs allows a deeper insight into the underlaying mechanisms, of for example the heat conduction, on an atomistic respectively molecular level. The non-equilibrium molecular dynamics (NEMD) method, intended to use here, provides through the explicit modeled thermal gradient additionally the opportunity to study coupling effects, like thermophoresis. To gain a detailed knowledge about the underlaying mechanisms, as well as whose dependency on molecular structure respectively composition, and the impact on the thermophysical properties, is vital for a purposive design of HTFs. Here we focus on ionic liquids (ILs) and suspensions of nano-particles in ionic liquids, so called ionanofluids or nano-particle-enhanced ILs (NEILs) as HTFs. Research focus 1 is concerned about pure ILs and the effect of different anion or cation types of the ILs and furthermore the influence of impurities, like water, chloride ions or organic solvents e.g., on the thermophysical properties. Research focus 2 is on NEILs and the additional effects and mechanisms due to the interactions of the ILs with nano-particles, which lead to the significant increase in thermal conductivity as it was shown in experiments.