温度对氧化镁与碳酸钙混合污垢特性影响的分子动力学模拟

Effect of Temperature on Composite Fouling Characteristics of Magnesium Oxide and Calcium Carbonate:a Molecular Dynamics Simulation

为了研究温度对MgO颗粒与碳酸钙混合污垢的影响,采用分子动力学模拟方法分析温度对体系内混合污垢的成核特性以及在换热表面混合污垢形成的影响。结果表明,随着温度的升高,MgO颗粒表面水合层和离子周围水合层致密程度减弱,离子的扩散系数增大,加速了体系中MgO颗粒与碳酸钙离子形成混合团聚物的速率。同时,温度的升高会导致换热表面吸附层中水分子数减少,所吸附的离子数增加,离子与颗粒沉积在换热表面概率增大,且沉积的团簇结构更加紧密,更容易促进换热表面混合污垢的形成。

The effect of temperature on the nucleation characteristics of composite fouling in the system and the formation of composite fouling on the heat exchange surface were studied using molecular dynamics simulation.The fouling was composed of MgO particle and calcium carbonate.The results show that with the increase of temperature,the compactness of the hydration layer on the surface of MgO particle and the hydration layer around ions decreases.But the diffusion coefficient of ions increases as temperature rises.As a result,the system’s rate of mixed aggregation of MgO particle and calcium carbonate ions is sped up.The extent of adsorbed ions will additionally develop as temperature rises.But water molecules in the layer of adsorption on the heat transfer surface will decrease.With the increase of temperature,the probability of ions and particles deposited on the heat transfer surface increases,but the deposited cluster structure is closer.Therefore,the increase of temperature is more likely to promote the formation of composite fouling on the heat transfer surface.