应用格子Boltzmann方法研究颗粒横掠管束的沉积过程

Lattice Boltzmann Simulation for the Particle Flow and Deposition on the Tube Bundles

烟气中灰尘颗粒在换热器管束表面的沉积对换热器性能有较大影响,研究颗粒在管束上的沉积规律有较大的应用价值。本文应用格子Boltzmann与格子气自动机的耦合模型模拟了颗粒随流场的运动,并采用该模型模拟了颗粒在单排管束表面的沉积现象,得到了直径为5μm和10μm的颗粒在管子上的沉积形貌。接着模拟了直径为10μm的颗粒在顺排和叉排管束表面的沉积形貌,结果显示前排管束只在背风面发生沉积,而后排管束在迎风面和背风面同时发生沉积,且顺排管束上的颗粒沉积较多。因此,叉排布置有利于减小积灰。本文的研究可以展示颗粒沉积的规律,并为含尘烟气换热器的设计提供指导。

The performances of the heat exchangers are influenced when the particles in the flue gas deposit on their surfaces.Therefore,to study the particle deposition pattern on the tube bundles has application values.In the present work,the lattice Boltzmann method and the lattice gas automata model are employed to simulate the particle transport in the flow field and the particle deposition process on the surface of a single tube.The deposition shapes of the particles with 5 μm and 10 μm diameters are obtained.Then,the 10 μm particle deposition processes on the aligned and staggered tube bundles are studied.The results show that the depositions only occur on the leeward side of the front row of tubes,while occur on both the windward and leeward side of the other rows.The deposition on the aligned bundles is relatively more.Therefore,the staggered tube bundle is beneficial to reduce the deposition.This research can reveal the pattern of the particle deposition and direct the design of the heat exchangers for the flue gases.