Lattice-Boltzmann simulation of heat transfer in turbulent pipe flows seeded with resolvednon-spherical particles

含有溶解非球形颗粒的湍流管流中传热的格子-玻尔兹曼模拟

• 批准号: 465872891
• 负责人: Professor Dr. Dominique Thévenin
• 金额: --
• 依托单位: Institut für Strömungstechnik und Thermodynamik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/465872891?language=en
• 关键词: Lattice; Boltzmann; simulation; heat; transfer

Turbulent flows laden with particles are ubiquitous in a wide range of industrial and natural processes including biomass combustion, pollutant transport, sand storms, icy clouds, etc. In most of these applications particle shape is not spherical. Numerical simulation of turbulent flows with non-spherical particles is complicated because the orientation and distribution of particles play an important role and can significantly modify flow and turbulence behavior. Most numerical studies dealing with turbulent flows involving non-spherical particles are limited to point particles. However, when particles become larger than the Kolmogorov length scale, simulations become more complex and demand large computational efforts. Very few numerical studies of turbulent flows with interface-resolved non-spherical particles can be found in the scientific literature up to now. Most of these studies have considered isothermal conditions. However, heat transfer from/to particles can again significantly alter all flow properties. Hot particles can also modify the turbulence spectra through pressure dilatation. Such effects have never been addressed thoroughly in the past. The goal of this study is to bridge this gap by performing direct numerical simulation (DNS) of turbulent flows containing non-spherical particles and considering heat transfer effects. Given the complexity of the problem and very high computational costs required for the simulations, a lattice Boltzmann method (LBM) solver is chosen for this study. Due to the locality of all operations, parallel computations are straightforward with LBM. Moreover, it can relatively easily be applied to complex domains, which makes it suitable for the purpose of the present proposal. To this end, an immersed boundary method (IBM) combined with an LBM solver will be employed. In order to deliver information relevant for practical applications, the final simulations will consider a pipe flow, opening the door for a better physical understanding of important phenomena like particle position in catalytic reactors, or fouling in heat exchangers. Such DNS (here based on LBM) will improve our understanding of the physical transfer mechanisms. Combining turbulence, non-isothermal and fluid dynamics aspects and considering the mutual interactions that occur during the motion of non-spherical particles are the central goals of this proposal. The results of this study will also enable practical progress concerning heat transfer enhancement, possibly coupled to drag-reduction effects.

在包括生物质燃烧、污染物输送、沙尘暴、冰云等在内的各种工业和自然过程中，携带颗粒的湍流是普遍存在的。非球形颗粒的湍流数值模拟比较复杂，因为颗粒的取向和分布对流动和湍流行为有很大的影响。大多数涉及非球形颗粒湍流的数值研究仅限于点状颗粒。然而，当粒子变得大于Kolmogorov长度比例时，模拟会变得更加复杂，并且需要大量的计算工作。到目前为止，在科学文献中对界面分辨非球形颗粒湍流流动的数值研究很少。这些研究中的大多数都考虑了等温条件。然而，从颗粒到颗粒的热传递会再次显著改变所有流动特性。热粒子还可以通过压力膨胀来修改湍流谱。这种影响在过去从未得到彻底解决。本研究的目的是通过对含有非球形颗粒的湍流进行直接数值模拟并考虑换热效应来弥补这一差距。考虑到问题的复杂性和模拟所需的很高的计算成本，本研究选择了格子Boltzmann方法(LBM)求解。由于所有操作的局部性，使用LBM可以直接进行并行计算。此外，它可以相对容易地应用于复杂的领域，这使其适合本提案的目的。为此，将使用浸没边界方法(IBM)和LBM求解器相结合。为了提供与实际应用相关的信息，最终的模拟将考虑管道流动，这为更好地物理理解重要现象打开了大门，例如催化反应器中的颗粒位置，或热交换器中的结垢。这样的域名(这里基于LBM)将提高我们对物理传输机制的理解。将湍流、非等温和流体动力学方面结合起来，并考虑非球形粒子运动过程中发生的相互作用，是这一提议的中心目标。这项研究的结果也将使关于强化换热的实际进展成为可能，这可能与减阻效应相耦合。