熔渣颗粒碰壁的相变沉积热过程模拟

Numerical Simulation of Molten Slag Depositing on the Wall Including Phase Change

离心粒化方法在高温熔渣余热回收方面具有结构紧凑、能耗低、得到的渣粒粒径小等优势。但受到粒化仓空间限制,会出现高温熔融渣粒碰撞、黏附在壁面的现象,影响装置运行的稳定性。本文针对该问题建立了熔融渣粒碰撞壁面的三维对称模型,结合VOF(流体体积)方法和凝固/融化模型来模拟熔渣动态形变和凝固换热过程。模拟得到,两个同粒径熔融渣粒在壁面上相继沉积会出现碰撞、铺展、回缩、飞溅、稳定的动态行为。进一步,讨论了熔渣初始温度和冷却风速对其形变和凝固换热的影响。结果表明,熔渣初始温度越小,铺展因数越小,凝固所需时间延长。而冷却风速(1~3 m/s)对熔渣碰壁过程中的铺展形变和换热的影响都很微小。

Aimed at waste heat recovery of high-temperature slag,the centrifugal granulation method has the advantages of compact structure,low energy consumption,small particle size of the obtained slag,and so on.Nevertheless,due to the limitation of the granulation chamber,the molten slag particles may collide and adhere to the wall,influencing the operational stability of the equipment.In this paper,a three-dimensional symmetrical model was established.The VOF method and the solidification/melting model were coupled to simulate the dynamic deformation of slag particle with phase change.The result shown that the dynamic behaviors of collision,spreading,retraction,splashing,and stabling occurred during two slag particles with same size impacting on the wall surface successively.The effects of initial temperature of slag droplet and wind speed on collision were further analyzed.It was indicated that the smaller the initial temperature of the slag,the smaller the spreading factor and the longer the time required for solidification.But the cooling wind speed(1~3 m/s) has little effect.