考虑温度效应的灰颗粒碰撞模型及沉积行为预测

Ash Particle Collision Model and Deposition Behavior Prediction Considering Temperature Effect

高温下积灰结渣影响着锅炉受热面经济与安全性。为研究温度作用下灰颗粒沉积特性,在他人提出的弹塑性碰撞模型基础上,通过对现有模型中的材料物性进行基于温度的修正,耦合颗粒碰撞传热模型,提出考虑温度效应的灰颗粒碰撞模型,并应用所提模型对灰颗粒沉积行为进行预测。研究发现,所提模型具有较高的适用性,能够精确地模拟温度效应下颗粒的反弹与沉积特性;临界粘附速度受平板温度的影响较大,在利用控温的方式减轻受热面积灰,应优先选择降低受热面的温度;温度升高不仅会造成小粒径颗粒沉积,也会造成中等粒径以上颗粒的沉积;当前模型与计算流体力学的耦合可应用于对受热管的沉积预测,预测精度较高。

Deposition and slagging under high temperature affected the economy and safety of boiler heating surface.To study the ash deposition characteristics under high temperature,this paper based on the elastic-plastic collision model proposed by Dong et al.and coupled with the particle impact heat transfer model,proposing an ash particle impact model according to the temperature effect by modifying the material properties of the existing model,and analyzed the ash particle deposition behavior with the proposed model.It is found that the proposed model has the high applicability and can accurately simulate the rebound and deposition characteristics of particles under different temperature.The critical adhesion velocity is greatly affected by the temperature of the plate,thus reducing the temperature of the heating surface,as a way of temperature control,should be the priority to reduce the ash deposition.High temperature will not only cause the deposition of small particle size,but also cause the deposition of medium particle size and above.The coupling between the proposed model and the computational fluid dynamics can be applied to the prediction of deposition on the heat-exchange tube,with high accuracy.