A computational fluid dynamics model is presented that allows for the investigation of the ash deposition and provides an economical approach for studying design changes in new boilers and retrofit options for existing units. This study proposes a detailed description of ash deposition integrating three separate particle-sticking criteria: melt fraction, viscosity, and energy conservation upon collision. Also, a detailed model for predicting the thermal properties of existing deposit layers (thermal conductivity and emissivity) is implemented into a one-dimensional wall heat-transfer model. The coupled ash-deposition and wall heat-transfer model is implemented into a large-eddy simulation (LES) framework to predict the heat-flux profile, deposition rates, slagging and fouling for industrial boilers. The results of this approach are validated with experimental data from the University of Utah’s 100 kW down-fired, oxy-fuel combustion (OFC) furnace. Two OFC cases with different geometries are studied for their coal combustion and dynamic ash-deposit growth in this large-scale laboratory furnace. Comparisons of the deposition rates and gas temperature agree within 4.82% and 17.58%, respectively, of the measured data.

提出了一种计算流体动力学模型，该模型可以研究灰分沉积，并为研究新型锅炉的设计变更和现有机组的改造选项提供了一种经济的方法。这项研究提出了对灰分沉积的详细描述，它结合了三个独立的颗粒粘附标准：熔体分数，粘度和碰撞时的能量守恒。而且，将用于预测现有沉积层的热特性（导热率和发射率）的详细模型实现为一维壁热传递模型。将灰烬沉积和壁面传热耦合模型应用到大涡流模拟（LES）框架中，以预测工业锅炉的热通量曲线，沉积速率，结渣和结垢。该方法的结果已由犹他大学的100 kW向下燃烧的氧燃料燃烧（OFC）炉的实验数据进行了验证。在这台大型实验室炉中，研究了两个具有不同几何形状的OFC箱的煤燃烧和动态灰烬增长的情况。沉积速率和气体温度的比较分别在测量数据的4.82％和17.58％之内。