摘要
针对锅炉管背风面飞灰沉积过程,采用数值模拟的方法进行了研究.对绕柱气相湍流的模拟采用了较新的分离涡模拟方法（detached eddy simulation, DES）,通过对粒径为1～10 μm的颗粒在圆管背风面碰撞分布规律的计算发现背风面近壁区存在的主涡、二次涡和分离点附近小涡对颗粒在背风面的碰撞均有一定的影响.当速度较小时,随着粒径的增大,颗粒在背风面碰撞的质量逐渐增加,大颗粒在主涡和二次涡作用下均有较大的碰撞质量流量,而且二次涡的作用明显强于主涡;速度增加后,由背风面3种涡结构引起的颗粒碰撞量均有不同程度的减少,此时主涡的作用较强,而且二次涡引起的大颗粒碰撞量有明显减少.通过与实验测试结果进行对比检验,证明了数值模拟结果的准确性.
Numerical simulations were conducted to study the deposition processes of fly ashes on the rear side surface of a boiler tube. Detached eddy simulation approach was applied to simulate the turbulent featurcs of gas around a cylinder. Impaction and distribution of 1 μm to 10 μm diameter particles on the rear side surface were predicted. Results suggested that the main vortex, secondary vortex and small vortex near the separation point, all contribute to particles＇ impaction on the rear side surface. When the velocity was low, with increasing of diameter, total mass of particles impacted on the rear side was augmented, and under the sway of the main vortex and secondary vortex, large particles usually had relatively large impaction quantities; while particles＇ impact concentration induced by the secondary vortex was apparently greater than that of main vortex. As velocity increased, influences of the above three kinds of vortices on the particles＇ impact concentration decreased. The influence of the main vortex was strengthened to greater than that of the secondary vortex, and the impaction concentration of large particles induced by the secondary particles decreased as well. The correctness of the simulation results was verified by the experimentally measured results.
出处
《浙江大学学报（工学版）》
EI
CAS
CSCD
北大核心
2006年第4期605-609,共5页
Journal of Zhejiang University：Engineering Science
基金
国家自然科学基金资助项目(60534030)
中国博士后科学基金资助项目(2005038623)
关键词
分离涡模拟方法(DES)
颗粒
涡结构
碰撞分布
detached eddy simulation
particles
vortex structure
impaction and distribution
